Am0001.pdf

Offers must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended, by one of the following methods:

(a) By completing items 8 and 15, and returning or (c) By separate letter or electronic communication which includes a reference to the solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGMENT TO BE RECEIVED AT THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN REJECTION OF YOUR OFFER. If by virtue of this amendment you desire to change an offer already submitted, such change may be made by letter or electronic communication, provided each letter or electronic communication makes reference to the solicitation and this amendment, and is received prior to the opening hour and date specified.

E. IMPORTANT: Contractor is not is required to sign this document and return copies to the issuing office.

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT 1. CONTRACT ID CODE

2. AMENDMENT/MODIFICATION NUMBER 3. EFFECTIVE DATE 4. REQUISITION/PURCHASE REQUISITION NUMBER 5. PROJECT NUMBER (If applicable)

7. ADMINISTERED BY (If other than Item 6) CODE

STANDARD FORM 30 (REV. 11/2016)

Prescribed by GSA FAR (48 CFR) 53.243

FACILITY CODE

9A. AMENDMENT OF SOLICITATION NUMBER

9B. DATED (SEE ITEM 11)

10A. MODIFICATION OF CONTRACT/ORDER NUMBER

10B. DATED (SEE ITEM 13)

11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS

The above numbered solicitation is amended as set forth in Item 14. The hour and date specified for receipt of Offers is extended. is not extended.

12. ACCOUNTING AND APPROPRIATION DATA (If required) copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted;

13. THIS ITEM APPLIES ONLY TO MODIFICATIONS OF CONTRACTS/ORDERS.

IT MODIFIES THE CONTRACT/ORDER NUMBER AS DESCRIBED IN ITEM 14.

CHECK ONE A. THIS CHANGE ORDER IS ISSUED PURSUANT TO: (Specify authority) THE CHANGES SET FORTH IN ITEM 14 ARE MADE IN THE CONTRACT ORDER

NUMBER IN ITEM 10A.

B. THE ABOVE NUMBERED CONTRACT/ORDER IS MODIFIED TO REFLECT THE ADMINISTRATIVE CHANGES (such as changes in paying office, appropriation data, etc.) SET FORTH IN ITEM 14, PURSUANT TO THE AUTHORITY OF FAR 43.103(b).

C. THIS SUPPLEMENTAL AGREEMENT IS ENTERED INTO PURSUANT TO AUTHORITY OF:

D. OTHER (Specify type of modification and authority)

Except as provided herein, all terms and conditions of the document referenced in Item 9A or 10A, as heretofore changed, remains unchanged and in full force and effect.

15C. DATE SIGNED

15A. NAME AND TITLE OF SIGNER (Type or print)

16C. DATE SIGNED

16A. NAME AND TITLE OF CONTRACTING OFFICER (Type or print)

14. DESCRIPTION OF AMENDMENT/MODIFICATION (Organized by UCF section headings, including solicitation/contract subject matter where feasible.)

PAGE OF PAGES

6. ISSUED BY CODE

8. NAME AND ADDRESS OF CONTRACTOR (Number, street, county, State and ZIP Code) (X)

CODE

15B. CONTRACTOR/OFFEROR

(Signature of person authorized to sign)

16B. UNITED STATES OF AMERICA

(Signature of Contracting Officer)

Previous edition unusable

Amendment No. 0001

Cavitation Repair, Gavins Point Dam, NE

See attached documentation for content of the amendment revisions

Date for receipt of Proposals is 20 February 2019 at 2:00 pm (local time)

Government Point of Contact: Jessica Jackson, Contract Specialist (402) 995-2052

U.S ARMY CORPS OF ENGINEERS, OMAHA DISTRICT

CONTRACTING OFFICE

1616 CAPITOL AVE.

OMAHA, NE 68102-4901

See Item 6

W9128F19R0019

01/23/2019

12/21/2018

01/23/2019

Am #0001 - 2 (Continuation SF 30)

23 January 2019 Solicitation No. W9128F19R0019

Date of Issue: 21 Dec 2018 New Date of Receiving Proposals: 20 Feb 2019

SUBJECT: Amendment No. 0001 to Request for Proposal Solicitation Package for Construction of Cavitation Repair, Gavins Point Dam, NE

TO: Prospective Offerors and Others Concerned

1. The specifications and drawings for subject project are hereby modified as follows (revise all specification indices, attachment lists, and drawing indices accordingly).

a. Specifications. (Descriptive Changes.)

(1) Section 00 10 00, SF1442 and CLIN Pricing Schedule, delete date and time of receiving proposals shown and substitute "20 February 2019" at "2:00".

b. Specifications (New and/or Revised and Reissued). Delete and substitute or add specification pages or sections as noted below. The substituted pages or sections are revised and reissued with this amendment.

Pages or Sections Deleted Pages or Sections Substituted or Added

General Wage Decision No NE180078 General Decision Number: NE190078 Dated 01/18/2019

SECTION 48 13 13.08 26 SECTION 48 13 13.08 26

CAVITATION AND CRACK REPAIR CAVITATION AND CRACK REPAIR

(See paragraph 1.8 & 3.5 for changes)

2. This amendment is a part of the proposing papers and its receipt shall be acknowledged. All other conditions and requirements of the request for proposal remain unchanged.

3. Offers will be received until 2:00 p.m., local time at place of receiving proposals, 20 February 2019, as stated in the Request For Proposal.

Attachment: General Decision Number: NE190078 dated 01/18/2019 Specification Sections as listed in 1.b above

U.S. Army Corps of Engineers, Omaha District 1616 Capitol Avenue Omaha, Nebraska 68102-4901

23 Jan 2019

MFS/2184

NE190078 Page 1 Am0001

General Decision Number: NE190078 01/18/2019 NE78

Superseded General Decision Number: NE20180078

State: Nebraska

Construction Type: Building

Counties: Antelope, Boyd, Brown, Burt, Cedar, Colfax, Cuming, Dodge, Holt, Keya Paha, Rock, Stanton and Wayne Counties in Nebraska.

BUILDING CONSTRUCTION PROJECTS (does not include single family homes or apartments up to and including 4 stories).

Note: Under Executive Order (EO) 13658, an hourly minimum wage of $10.60 for calendar year 2019 applies to all contracts subject to the Davis-Bacon Act for which the contract is awarded (and any solicitation was issued) on or after January 1, 2015. If this contract is covered by the EO, the contractor must pay all workers in any classification listed on this wage determination at least $10.60 per hour (or the applicable wage rate listed on this wage determination, if it is higher) for all hours spent performing on the contract in calendar year 2019. If this contract is covered by the EO and a classification considered necessary for performance of work on the contract does not appear on this wage determination, the contractor must pay workers in that classification at least the wage rate determined through the conformance process set forth in 29 CFR 5.5(a)(1)(ii) (or the EO minimum wage rate,if it is higher than the conformed wage rate). The EO minimum wage rate will be adjusted annually. Please note that this EO applies to the above-mentioned types of contracts entered into by the federal government that are subject to the Davis-Bacon Act itself, but it does not apply to contracts subject only to the Davis-Bacon Related Acts, including those set forth at 29 CFR 5.1(a)(2)-(60). Additional information on contractor requirements and worker protections under the EO is available at www.dol.gov/whd/govcontracts.

Modification Number Publication Date 0 01/04/2019 1 01/18/2019

BOIL0083-002 01/01/2017

Rates Fringes

BOILERMAKER......................$ 36.56 28.11

BRNE0001-006 06/04/2018

BURT, CEDAR, COLFAX, CUMING, DODGE, STANTON, AND WAYNE COUNTIES

Rates Fringes

NE190078 Page 2 Am0001

BRICKLAYER.......................$ 28.95 16.07

BRNE0001-007 06/01/2014

ANTELOPE, BOYD, BROWN, HOLT AND KEYA PAHA COUNTIES

Rates Fringes

BRICKLAYER.......................$ 23.99 12.66

CARP0427-007 06/01/2017

ANTELOPE, BURT, COLFAX, CUMING, DODGE, STANTON AND WAYNE

COUNTIES

CARPENTER (Drywall Hanging Only)............................$ 25.91 13.15

ELEC0022-002 06/01/2018

BURT, COLFAX, CUMING, DODGE AND STANTON COUNTIES

Rates Fringes

ELECTRICIAN......................$ 35.90 15.74

ELEC0231-009 06/01/2018

CEDAR AND WAYNE COUNTIES

Rates Fringes

ELECTRICIAN......................$ 33.32 14.15

ELEC0265-004 06/03/2018

ANTELOPE, BOYD, BROWN, HOLT, KEYA PAHA AND ROCK COUNTIES

Rates Fringes

ELECTRICIAN

Zone 1......................$ 29.28 11.84 Zone 2......................$ 29.58 11.85 Zone 3......................$ 29.89 11.87 Zone 4......................$ 30.29 11.88

ZONE DEFINITIONS:

Zone 1: 0 to 35 miles from the main Post Office in Lincoln Zone 2: 36 to 50 miles from the main Post Office in Lincoln Zone 3: 51 to 75 miles from the main Post Office in Lincoln Zone 4: 76 miles and over from the main Post Office in Lincoln

NE190078 Page 3 Am0001

* ELEV0028-001 01/01/2019

Rates Fringes

ELEVATOR MECHANIC................$ 44.48 33.705+a+b

FOOTNOTE:

a. Vacation Pay: 8% for persons with 5 or more years of service, 6% for persons with less than 5 years of service.

b. Paid Holidays: New Year's Day, Memorial Day, Independence Day, Labor Day, Veterans' Day, Thanksgiving Day, Friday after Thanksgiving, and Christmas Day.

IRON0021-010 06/01/2017

BURT, COLFAX AND DODGE COUNTIES

Rates Fringes

IRONWORKER, STRUCTURAL...........$ 29.09 15.52

IRON0021-011 06/01/2017

ANTELOPE, BOYD, BROWN, CEDAR, CUMING, HOLT, KEYA PAHA, ROCK,

STANTON AND WAYNE COUNTIES

IRONWORKER, STRUCTURAL...........$ 23.18 15.31

LABO1140-010 06/01/2016

Rates Fringes

LABORER (Mason Tender, Brick & Hod)...........................$ 20.63 9.40

PLUM0016-003 05/06/2018

Rates Fringes

PLUMBER (Excluding HVAC Pipe Installation)....................$ 35.45 13.81

* PLUM0464-019 06/01/2017

Rates Fringes

PIPEFITTER (Includes HVAC Pipe Installation)...............$ 35.74 17.11

SFNE0669-001 04/01/2017

NE190078 Page 4 Am0001

SPRINKLER FITTER (Fire Sprinklers)......................$ 34.75 15.84

SHEE0003-020 07/01/2015

BROWN, BURT, COLFAX, CUMING, DODGE, KEYA PAHA, ROCK AND STANTON

COUNTIES

SHEET METAL WORKER (Includes HVAC Duct Installation)..........$ 32.89 14.93

SHEE0003-021 05/01/2012

ANTELOPE, BOYD, CEDAR, HOLT AND WAYNE COUNTIES

Rates Fringes

SHEET METAL WORKER (Includes HVAC Duct Installation)..........$ 22.41 10.29

SUNE2012-015 04/19/2012

Rates Fringes

CARPENTER, Excludes Drywall Finishing/Taping, and Drywall Hanging..........................$ 17.39 3.13

CEMENT MASON/CONCRETE FINISHER...$ 17.80 1.34

DRYWALL FINISHER/TAPER...........$ 13.79 3.32

LABORER: Common or General......$ 12.07 2.85

OPERATOR:

Backhoe/Excavator/Trackhoe.......$ 21.82 2.22

OPERATOR: Loader.................$ 16.58 0.94

ROOFER...........................$ 14.52 0.65

TRUCK DRIVER: Dump, Lowboy and Tandem.......................$ 14.56 1.68

WELDERS - Receive rate prescribed for craft performing operation to which welding is incidental.

Note: Executive Order (EO) 13706, Establishing Paid Sick Leave for Federal Contractors applies to all contracts subject to the Davis-Bacon Act for which the contract is awarded (and any

NE190078 Page 5 Am0001 solicitation was issued) on or after January 1, 2017. If this contract is covered by the EO, the contractor must provide employees with 1 hour of paid sick leave for every 30 hours they work, up to 56 hours of paid sick leave each year.

Employees must be permitted to use paid sick leave for their own illness, injury or other health-related needs, including preventive care; to assist a family member (or person who is like family to the employee) who is ill, injured, or has other health-related needs, including preventive care; or for reasons resulting from, or to assist a family member (or person who is like family to the employee) who is a victim of, domestic violence, sexual assault, or stalking. Additional information on contractor requirements and worker protections under the EO is available at www.dol.gov/whd/govcontracts.

Unlisted classifications needed for work not included within the scope of the classifications listed may be added after award only as provided in the labor standards contract clauses (29CFR 5.5 (a) (1) (ii)).

The body of each wage determination lists the classification and wage rates that have been found to be prevailing for the cited type(s) of construction in the area covered by the wage determination. The classifications are listed in alphabetical order of "identifiers" that indicate whether the particular rate is a union rate (current union negotiated rate for local), a survey rate (weighted average rate) or a union average rate (weighted union average rate).

Union Rate Identifiers

A four letter classification abbreviation identifier enclosed in dotted lines beginning with characters other than "SU" or "UAVG" denotes that the union classification and rate were prevailing for that classification in the survey. Example:

PLUM0198-005 07/01/2014. PLUM is an abbreviation identifier of the union which prevailed in the survey for this classification, which in this example would be Plumbers. 0198 indicates the local union number or district council number where applicable, i.e., Plumbers Local 0198. The next number, 005 in the example, is an internal number used in processing the wage determination. 07/01/2014 is the effective date of the most current negotiated rate, which in this example is July 1, 2014.

Union prevailing wage rates are updated to reflect all rate changes in the collective bargaining agreement (CBA) governing this classification and rate.

Survey Rate Identifiers

Classifications listed under the "SU" identifier indicate that no one rate prevailed for this classification in the survey and

NE190078 Page 6 Am0001 the published rate is derived by computing a weighted average rate based on all the rates reported in the survey for that classification. As this weighted average rate includes all rates reported in the survey, it may include both union and non-union rates. Example: SULA2012-007 5/13/2014. SU indicates the rates are survey rates based on a weighted average calculation of rates and are not majority rates. LA indicates the State of Louisiana. 2012 is the year of survey on which these classifications and rates are based. The next number, 007 in the example, is an internal number used in producing the wage determination. 5/13/2014 indicates the survey completion date for the classifications and rates under that identifier.

Survey wage rates are not updated and remain in effect until a new survey is conducted.

Union Average Rate Identifiers

Classification(s) listed under the UAVG identifier indicate that no single majority rate prevailed for those classifications; however, 100% of the data reported for the classifications was union data. EXAMPLE: UAVG-OH-0010 08/29/2014. UAVG indicates that the rate is a weighted union average rate. OH indicates the state. The next number, 0010 in the example, is an internal number used in producing the wage determination. 08/29/2014 indicates the survey completion date for the classifications and rates under that identifier.

A UAVG rate will be updated once a year, usually in January of each year, to reflect a weighted average of the current negotiated/CBA rate of the union locals from which the rate is based.

WAGE DETERMINATION APPEALS PROCESS

1.) Has there been an initial decision in the matter? This can be:

* an existing published wage determination

* a survey underlying a wage determination

* a Wage and Hour Division letter setting forth a position on a wage determination matter

* a conformance (additional classification and rate) ruling

On survey related matters, initial contact, including requests for summaries of surveys, should be with the Wage and Hour Regional Office for the area in which the survey was conducted because those Regional Offices have responsibility for the Davis-Bacon survey program. If the response from this initial contact is not satisfactory, then the process described in 2.)

and 3.) should be followed.

With regard to any other matter not yet ripe for the formal

NE190078 Page 7 Am0001 process described here, initial contact should be with the Branch of Construction Wage Determinations. Write to:

Branch of Construction Wage Determinations Wage and Hour Division U.S. Department of Labor 200 Constitution Avenue, N.W.

Washington, DC 20210

2.) If the answer to the question in 1.) is yes, then an interested party (those affected by the action) can request review and reconsideration from the Wage and Hour Administrator (See 29 CFR Part 1.8 and 29 CFR Part 7). Write to:

Wage and Hour Administrator U.S. Department of Labor 200 Constitution Avenue, N.W.

Washington, DC 20210

The request should be accompanied by a full statement of the interested party's position and by any information (wage payment data, project description, area practice material, etc.) that the requestor considers relevant to the issue.

3.) If the decision of the Administrator is not favorable, an interested party may appeal directly to the Administrative Review Board (formerly the Wage Appeals Board). Write to:

Administrative Review Board U.S. Department of Labor 200 Constitution Avenue, N.W.

Washington, DC 20210

4.) All decisions by the Administrative Review Board are final.

END OF GENERAL DECISION

Cavitation Repair, Gavins Point Dam, NE GP56

SECTION TABLE OF CONTENTS

DIVISION 48 - ELECTRICAL POWER GENERATION

SECTION 48 13 13.08 26

CAVITATION AND CRACK REPAIR

PART 1 GENERAL

1.1 GENERAL INFORMATION

1.2 REFERENCES

1.3 SUBMITTALS

1.4 WELDING REQUIREMENTS

1.5 SAFETY REQUIREMENTS

1.6 FILLER METAL REQUIREMENTS

1.7 NON-DESTRUCTIVE TESTING

1.8 DRAFT TUBE PLATFORM & DEBRIS NETTING

1.9 VENTILATION (FOR SITE OPERATIONS)

PART 2 PRODUCTS

2.1 WELDING PRODUCTS

PART 3 EXECUTION

3.1 GENERAL

3.2 WELD PROCESSES, PROCEDURES AND REQUIREMENTS

3.2.1 Terminology

3.2.2 Welding Qualifications and Requirements

3.2.3 Bearing Protection

3.2.4 Copper Sulfate Base Metal Checks

3.3 FINISH

3.4 FAIRNESS

3.5 WORK PLAN

3.5.1 Work Plan Submittal Details

3.6 DISCHARGE RING CAVITATION REPAIR

3.6.1 Repair General Requirements

3.6.2 Unit Rotation

3.6.3 Discharge Ring Template

3.6.3.1 Template Fabrication

3.6.3.2 Template Alignment for Measurements

3.6.3.3 Template Measurements

3.6.3.4 Template Measurement Indexing Details

3.6.3.5 Template Measurement Submittal Requirements

3.6.3.6 Template Measurement Government Witness

3.6.4 Removal of Damaged Material

3.6.4.1 48-Inch Discharge Ring Circumferential Band (1/4-inch depth)

3.6.5 Spot Repair of Cavitation Damage

3.6.6 Stainless Steel Plate Removal

3.6.7 Inspection of Excavated Surfaces

3.6.8 Final Excavation Report

3.6.9 Base Metal Spot Repair in Discharge Ring

3.6.10 Locate Support Ribs

3.6.11 Discharge Ring Anchorage

3.6.11.1 Anchor Grouting Requirements

3.6.12 Thickness Inspections of Circumferential Band

3.6.12.1 Ultrasonic Testing Thickness Inspection

SECTION 48 13 13.08 26 Page 1 Am0001

3.6.12.2 Destructive Testing

3.6.13 Authorization to Start Weld Repair

3.6.14 Depth of Weld Repair Filler Metals

3.6.15 Weld Interpass Temperature Restrictions

3.6.16 Mild Steel Overlay of Circumferential Band(s)

3.6.17 Stainless Steel Overlay of Circumferential Band(s)

3.6.17.1 Overlay Application

3.6.18 Intermediate Inspections of All Repairs

3.6.18.1 Acceptance Criteria

3.6.18.2 Submittal Requirements

3.6.18.3 Additional Weld Inspection

3.6.18.4 Government Quality Assurance Weld Inspection

3.6.19 Repairs

3.6.20 Grouting Voids

3.7 SPOT REPAIR OF CAVITATION DAMAGE

3.7.1 Blade Inspection Prior to Repair

3.7.2 Commencement and Estimate of Work

3.7.3 Cavitation Damage Repair

3.7.3.1 Cavitation Damage Repair - Preparation and Inspection

3.7.3.2 Cavitation Damage Repair - Weld Metal Placement and

Inspection

3.7.4 Crack Repair

3.7.4.1 Crack Repair - Preparation and Inspection.

3.7.4.2 Crack Repair - Weld Metal Placement and Inspection

3.8 FINAL INSPECTION

3.8.1 Government Witness of Final Inspections

3.8.2 Post Repair Clearance Readings

3.8.3 Final Concentricity Measurements

3.8.4 Final Finish and Fairness Inspection

3.9 INSPECTION CLEANUP

-- End of Section Table of Contents --

SECTION 48 13 13.08 26 Page 2

SECTION 48 13 13.08 26

CAVITATION AND CRACK REPAIR

PART 1 GENERAL

1.1 GENERAL INFORMATION

The work covered by this section consists of providing all labor, technical expertise, materials, equipment, scaffolding and appurtenances necessary to accomplish the following turbine cavitation repairs for the waterway passage of all Units (1-3) at Gavins Point Powerhouse:

a. Perform cavitation damage repair on the turbine discharge ring. A portion (48-inches) of the existing discharge ring material must be ground or milled to good metal and anchoring provided. The discharge ring then will be spot repaired, built up with mild steel weld metal, stainless steel weld overlay placed, and the discharge ring surface ground and machined to the finished profile. This work will also include the repair of porosity exposed on the stainless overlay and weld seams of the discharge ring during cavitation repair, if necessary.

b. Note that Non-Destructive Testing (NDT) is required at various steps during this work, and is considered inclusive to this work. See paragraphs 3.1 and 3.6 for more details.

c. An example anchoring pattern is shown on Contract Drawing M-502.

This drawing may show more anchoring than may be required for the 48-inch overlay. Locations of necessary anchoring will be determined after the discharge ring vertical and horizontal stiffeners have been located with NDT and the centerline of repair has been submitted and approved.

d. Cavitation repair and crack repair must also be performed on the turbine blades, turbine hub and other water passage components as directed by the Government.

e. This work is in addition to the requirements of SECTION 03 64 23.00 26, EPOXY-INJECTION OF THE DISCHARGE RING/LINER. In the event that other cavitation/erosion damage or cracks are discovered, perform repairs at the discretion of the Government according to the requirements of this specification section.

f. The unit will not be unwatered until all pre-mobilization submittals have been submitted and approved by the Government. After unwatering, the draft tube will have approximately 18 inches of standing water below the platform/working area, depending on sealing.

g. All work will be accomplished with the unit remaining assembled. The Kaplan blades are functional and can be pitched, as desired, although the government anticipates flat blades for the duration of the work.

The blades will need to be held in place during material removal and welding. Equipment can not be passed straight down between the turbine blades unobstructed when the turbine blades are at full pitch. The blades overlap enough that it would not be an unobstructed drop for equipment even with the turbine blades at full pitch. The pitch can be

SECTION 48 13 13.08 26 Page 3 adjusted but there will always be an overlap. The turbine blades are adjustable from 0 degrees in flat, to 28 degrees when fully pitched.

h. Throughout this section "overlay" is used to describe the application/welding of the stainless steel onto the carbon steel discharge ring.

i. Previous stainless steel repairs are present in the water passage.

The plant annually deposits approximately 100 lbs of stainless steel, in welding repairs. Do not disturb these areas unless the repairs are failing, and are identified for repair by the Government; this is not possible in the band area of repair.

j. Contractors may apply temporary welds to the stay vanes, wicket gates, draft tube liner, etc. with the requirement that they are grounded and do not pass current through the bearings. There must be no visible indication of the temporary weld after removal, and it must not affect the operation of the unit afterwards.

h. The intent throughout this section is such that the final overlay of stainless steel is 0.2500 to 0.3125 inch, as required by this Section.

Any repairs that are deeper, are to be built up with mild steel, as described in this Section, such that the stainless repair overlay (atop the mild steel repair) will have a depth of 0.2500 to 0.3125 inch.

1.2 REFERENCES

The publications listed below form a part of this specification to the extent referenced. If referenced in the text, the publications are referred to by basic designation only.

ASME INTERNATIONAL (ASME)

ASME BPVC SEC II-C (2015) Boiler Pressure Vessel Code Section II-Materials Part C-Specifications for Welding Rods Electrodes and Filler Metals

INTERNATIONAL ELECTROTECHNICAL COMMISSION (IEC)

IEC 60609-1 (2004) Hydraulic turbines, storage pumps and pump-turbines Cavitation pitting evaluation Part 1: Evaluation in reaction turbines, storage pumps and pump-turbines

- Edition 1.0

AMERICAN SOCIETY OF SAFETY ENGINEERS (ASSE/SAFE)

ASSE/SAFE A10.11 (2013) Operations - Safety Requirements for Powder Actuated Fastening Systems

U.S. ARMY CORPS OF ENGINEERS (USACE)

EM 385-1-1 (2014) Safety and Health Requirements Manual

1.3 SUBMITTALS

Government approval is required for submittals with a "G" designation;

submittals having an "I" designation are for information only. Designation

SECTION 48 13 13.08 26 Page 4 following the "G" or "I" designation identifies the office that will review the submittal for the Government. Submit the following in accordance with

SECTION 01 33 00 SUBMITTAL PROCEDURES:

SD-05 Design Data

Work Plan; G, HDC

Ventilation System; G, DO

Discharge Ring Contour Template Design; G, HDC

Method of Performing Inspections, Recording Inspection Points, and Recording the Data; G, HDC

Method of Checking for Voids; G, HDC

Welding Repair Plan; G, HDC

Discharge Ring Anchoring - Template Drawing; G, HDC

Discharge Ring Circumferential Band Metal Removal Plan; G, HDC

Method And Procedure For Determining The Excavated Volume; G, HDC

SD-06 Test Reports

Report of Findings on Surface Cracks and Pin Holes; G, HDC

Finish And Fairness Inspection; G, HDC

Final Excavation Report; G, HDC

Report Of Weld Inspection; G, HDC

Report Of The Findings Of The Blade Inspection; G, HDC

Post Repair Clearance Readings; G, HDC

Final Concentricity Measurements; G, HDC

Template Measurements A - Before Excavation; G, HDC

Template Measurements B - Before Overlay; G, HDC

Template Measurements C - After Final Machining; G, HDC

Support Rib Location Report; G, HDC

SD-07 Certificates

Onsite CWI; G, HDC

Daily Certification; I, HDC

Template Sign-Off Sheet; G, HDC

Welder Performance Qualification (WPQ) Record;G, HDC

SECTION 48 13 13.08 26 Page 5

Notification of Excavated Volume Measurement; I, HDC

Notification of Weld Thickness Measurement; I, HDC;

Notification of Final Inspections; I, HDC

Notification Of Crack Inspection; I, HDC

Notification Of Excavated Surfaces Inspection; I, HDC

Notification Of Concentricity Measurements; I, HDC

Notification Of Template Measurements A - Before Excavation; I, HDC

Notification Of Template Measurements B - Before Overlay; I, HDC

Notification Of Template Measurements C - After Final Machining;

I, HDC

1.4 WELDING REQUIREMENTS

Specification SECTION 05 05 23.16 26, WELDING, does not apply to the work specified and performed under the requirements of this SECTION 48 13 13.08 26. Use the welding requirements within this SECTION for the work described in this SECTION.

1.5 SAFETY REQUIREMENTS

Perform work in accordance with safety requirements contained in Corps of Engineers Safety and Health Requirements Manual, EM 385-1-1. The working area shown in Detail 1 of M-301 is a permit required confined space until ventilated. Once ventilated it is a non-permit required confined space.

Contractors will be responsible for managing their confined space porgram, in accordance with OSHA. Ventilation fans are to be supplied by the contractor. See paragraph "VENTILATION (FOR SITE OPERATIONS)" below for more details and requirements.

1.6 FILLER METAL REQUIREMENTS

Provide weld filler metal conforming with ASME BPVC SEC II-C SFA-5.02,.

Specification for Filler Metal Standard Sizes, Packaging, and Physical Attributes.

1.7 NON-DESTRUCTIVE TESTING

The requirements for all non-destructive testing (NDT) is specified in SECTION 05 05 33.20 26, NON-DESTRUCTIVE TESTING. Instruction for non-destructive testing, as well as acceptance standards will be detailed within this section

1.8 DRAFT TUBE PLATFORM & DEBRIS NETTING

For draft tube scaffolding to serve as a work platform see SECTION 05 50 05.00 26. The draft tube door can be removed via hinge pins, but the door frame will remain undisturbed during this work. Installation of the Turbine Maintenance Platform (TMP) will be the responsibility of the Contractor. Government personnel will be onsite and available to assist in the assembly of the platform, with 7 days notice.The government will install the Turbine Maintenance Platform (TMP) with three days notice. For

SECTION 48 13 13.08 26 Page 6 planning purposes, the TMP installation will take 6-8 hours. The two main cantilevers that support the TMP extend from the draft tube, through the draft tube doorway, into support jacks. These supports cannot be removed.

Debris netting will be required under the work platform, per ASSE/SAFE A10.11. The debris netting is required to be installed prior to the commencement of any work above the draft tube, and remain in place until the completetion of work. The debris netting will be provided and installed by the Contractor, with no Government support.

1.9 VENTILATION (FOR SITE OPERATIONS)

Use an approved type of Ventilation System, such as mechanical exhaust ventilation, to remove the welding vapors and dust at the source and to dilute the concentration of welding vapors in an enclosed working space to a concentration that is safe for the entire work period, and submit at least 30 calendar days prior to using the ventilation system. Meet the requirements of EM 385-1-1 for ventilation. Vent gases and debris to the exterior of the powerhouse in such a manner as to not create a hazard for project tourists or employees. Prevent welding vapors from entering electrical components in the powerhouse. For welding within the turbine water passage, ventilate to the atmosphere unless otherwise approved. All ventilation equipment will be provided by the Contractor.

PART 2 PRODUCTS

2.1 WELDING PRODUCTS

a. The stick electrodes or wire shall match the tensile strength properties of the base metal, unless otherwise approved.

b. The stainless steel overlay shall be applied using type 309L material.

PART 3 EXECUTION

3.1 GENERAL

See paragraph 1.1 for a general description of the work to be completed, as well as noteworthy items. The work includes, but is not limited to, the summary identified below. The detailed scope of work is identified throughout this document.

1. Fabrication of a template for maintaining discharge ring profile;

2. Non destructive testing, verifying absence of blade cracking;

4. Pre-repair measurements (template clearances);

5. Machining/removal of material from the discharge ring;

6. NDT to locate the horizontal and vertical support ribs;

7. Anchoring in discharge ring (See 03 64 23.00 26)

8. Spot repair mapping and excavation (discharge ring, blades, hub)

9. Additional pre-repair measurements;

10. NDT prior to stainless steel overlay;

11. Weld overlay discharge ring with ¼ inch depth of stainless steel;

12. Rough machining of stainless steel overlay;

13. Check for (and epoxy grout) any voids, plug grout holes;

14. NDT after stainless steel overlay;

15. Finish machining of stainless steel overlay;

16. NDT after final machining;

17. Spot repairs to discharge ring, blades and hub;

SECTION 48 13 13.08 26 Page 7

18. Post-repair measurements (template clearances).

3.2 WELD PROCESSES, PROCEDURES AND REQUIREMENTS

The requirements identified under this paragraph and all its sub-paragraphs apply to all welding and welds required to be performed for the work described by this Section 48 13 13.08 26.

3.2.1 Terminology

Unless explicitly stated otherwise, the term 'weld' or 'welding' as used throughout this Section 48 13 13.08 26, includes 'overlay' and/or 'weld overlay'.

3.2.2 Welding Qualifications and Requirements

All welds and welding must conform to the requirements of BPVC Section IX.

Note the following:

a. The circumferential band weld overlay of both the mild steel and the stainless steel overlay is considered "hard-facing weld metal overlay" as defined by BPVC Section IX, Article QW-216 and must comply with the requirements of that article.

b. All welders must be qualified to perform their respective welds per the requirements of BPVC Section IX, Article III. Submit Welder Performance Qualification (WPQ) Records to the Government not less than 20 days prior to welding being performed by the welder.

c. All welding operations, including but not limited to set-up, preparation, welding, and inspection of welds must be monitored by an individual who is a Certified Welding Inspector (CWI) or a Senior Certified Welding Inspector (SCWI). Throughout this Section, any reference to or requirement of a CWI will also apply to the SCWI. The CWI and SCWI must be certified per the requirements of AWS QC1. Submit certification details for the Onsite CWI. At any time, if the onsite CWI changes, resubmit the certification details.

d. The CWI must be physically present at the job site any time welding or welding preparation is occurring, The CWI must certify that all welding complies with submitted WPS, and that all welders are qualified, per BPVC Section IX Article III, to perform their welds. CWI certification that all welds comply with submitted WPS and that all welders are qualified to perform their respective welds must be submitted daily on any day that welding is being performed. This Daily Certification must be in the form of a tabulation, listing, at a minimum, each weld being performed, the WPS which applies to the weld, the welder performing the weld, and the WPQ record that qualifies the welder.

e. Do not weld on the stainless steel wicket gate seal area unless approved in writing by the Government. Protect the bottom ring and head cover facing plates from weld splatter by the use of protective cloth

f. All welding rod, electrodes and filler metals must comply with the applicable portions of BPVC Section II, Part C.

g. The original blade material, as shown in the drawings, is QQ-S-681-B Class 2. The blades have been weld repaired over the years with

SECTION 48 13 13.08 26 Page 8 stainless steel, specifically Blue Max MIG 309LSi.

3.2.3 Bearing Protection

The Contractor must protect the generator and turbine bearings from damage by welding currents. A procedure for insulating/protecting the bearings must be submitted as part of the Work Plan, detailed in paragraph 3.5.

3.2.4 Copper Sulfate Base Metal Checks

If there is a reasonable possibility that stainless steel material exists at the bottom of an excavation, the Contractor must use copper sulfate to check for the presence of stainless steel in the bottom of the excavation(s) prior to performing a repair or overlay that uses mild steel filler metal. The copper sulfate must be mixed with water, approximately 85 percent water to 15 percent copper sulfate by weight. This mixture must be applied with a rag to the prepared surfaces. The base metal will turn a bronze color and the stainless steel will remain shiny. If stainless steel is found, immediately notify the Government and the Government will determine if additional excavation is to be performed, or if the repair weld filler metal will be 100% stainless steel. In no circumstance will mild (carbon) steel be placed on top of stainless steel.

3.3 FINISH

The final water passage surface of all new welds and overlays must be machined or ground to the original (or new) design contour as shown on the drawings and faired into the adjacent surfaces as specified herein. The surface finish of new weld surfaces, or of existing base metal that is ground or machined to meet the fairness requirements, must be 125 micro inches or better.

3.4 FAIRNESS

The finished water passageway surface of all welds, overlays, and areas adjacent to the new welds and overlays must have a fairness X/U ratio of less than 0.015, unless otherwise approved. If a step or other surface deviation exists between the new weld or overlay and the adjacent, un-repaired, base metal, the base metal must be machined or ground to achieve this fairness. X is the distance (inches) from a low point on the water passageway surface to the bottom of a flexible reference device (typically a flexible stick) placed on the surface. U is the length over which the reference device does not contact the water passageway surface.

Achieving this fairness requirement must be considered as incidental to the work and no additional payment must be made for meeting this requirement.

3.5 WORK PLAN

A complete Work Plan must be prepared and submitted for approval a minimum of 60 calendar days prior to mobilizing to the site. This Work Plan must address all of the welding identified in this Section, including weld overlay of both mild steel and stainless steel, crack repair and spot cavitation repair. Further details for the interfacing with and operation of Government equipment will be provided upon award, for drafting of the Work Plan (for example, bearing pump details). Information included in the Work Plan must include, but is not limited to:

a. The overall plan and sequence for the welding work;

b. Time-based schedule for performing the work (a Gantt Chart);

SECTION 48 13 13.08 26 Page 9

c. The procedure for monitoring distortion and deformation of the base metal(s);

d. Method and plan for monitoring interpass temperatures;

e. Location(s) where each Weld Procedure will be used;

f. Non-destructive examination plan;

g. Weld defect repair plan;

h. Welding electric current insulation plan;

i. Weld Procedure Specifications (WPS) for all welds being performed;

j. Procedure Qualification Records (PQR) for all welds being performed;

k. Unit Rotation Plan (if the unit is being rotated). The Unit Rotation Plan must identify the method(s) used to rotate the unit and how the bearings will be protected from damage during rotation. Include details for coordination using the high-lift pump, to ensure the thrust bearings are appropriately lubricated before every instance of unit rotation. Similarly, include details for coordination with the turbine guide bearing pump, to ensure the turbine guide bearing is appropriately lubricated during shaft rotation.

l. Blade position locking strategy, showing how the blade positions will be maintained during machining and welding processes.

m. Method of performing inspection, recording inspection points, and recording the data.

n. Method of determining the turbine guide bearing center, locating the old discharge ring centerline, as well as the new discharge ring centerline.

3.5.1 Work Plan Submittal Details

The Work Plan must include tables or diagrams showing the procedure to be used for each required geometry or welding method. No work on the turbine will begin until the Work Plan has been approved by the Government. If during the performance of the work it is discovered that changes need to be made to the Work Plan, a revised Work Plan must be submitted to the Government. The revised document must be submitted not less than 5 days prior to performing work that is addressed by the revisions.

3.6 DISCHARGE RING CAVITATION REPAIR

3.6.1 Repair General Requirements

Refurbish the discharge ring by removing material from the existing ring using machining, sanding, or grinding methods; repair and overlay welding;

and surface finishing of the welded areas by machining and/or grinding, unless otherwise approved. Localized cavitation and surface damaged areas must also be repaired as directed

3.6.2 Unit Rotation

It is anticipated but not required that the turbine runner/generator rotor assembly will be used during cavitation repair of the discharge ring. The entire turbine runner/generator rotor assembly may be rotated to facilitate the machining, grinding and/or welding operations. Use the existing generator thrust bearing oil lift pump whenever the unit is rotated. This pump is rated for 100% duty cycle. A protective device must be furnished to shut down the unit rotation drive upon low oil pressure in the thrust bearing oil lift system. Actual rotation of the unit must be accomplished by the Contractor with Contractor provided equipment. This equipment must include, but is not limited to, a motor, drive, and controls for turning the unit. Power must be delivered to rotating equipment through the use of a slip ring assembly, unless otherwise approved. Historically, these units

SECTION 48 13 13.08 26 Page 10 vary greatly in difficulty rotating. Multiple turning motors and sizes of motors, idler wheels, may need to be incorporated to rotate the unit. The unit must only be rotated in the same direction as it is operated.

3.6.3 Discharge Ring Template

Prior to beginning work on the discharge ring, one discharge ring contour template must be fabricated for use on the discharge ring for all three Units. See the following reference drawing, Baldwin-Lima-Hamilton (BLH) Drawing No. 39519. These templates must conform to the original design shape.

3.6.3.1 Template Fabrication

The Contractor supplied template must be constructed of 10 gage 6061 T6 aluminum or approved equal that allows accurate checking of the contours of the discharge ring work surface. At the conclusion of the discharge repair work the template must be supplied to the government as a special tool.

The Discharge Ring Contour Template Design must be submitted for approval a minimum of 60 calendar days prior to the contractor mobilizing to the site.

Include a horizontal line marked "Center of Blade" which corresponds to the axis of blade rotation. Pertinent dimensions are found on the included reference drawings.

3.6.3.2 Template Alignment for Measurements

The template must be positioned on the rotative device (the blades with the runner in place, or an alternate fixture) such that the horizontal line marked "Center of Blade" on the template lines up with the elevation of the centerline of blade rotation. Position and size the template such that it does not come into contact with the discharge ring when all repairs have been completed. The proper positioning of the template should be established by use of the vertical "cross-hair" markings on the template drawing, unless otherwise approved. These markings should be transferred to the template. The markings on the template should then be aligned with a "plumb bob" line or other suitable devices. The attachment of the template to the rotating device should be such that the template's position can be adjusted and set, and such that it can be removed and replaced without the need for realignment. The Government will witness the placement and alignment of the template. Submit a Notification of Template Measurements a minimum of 24 hours before all three inspection points detailed in paragraph 3.6.3.5, Template Measurement Submittal Requirements. Both the Contractor and the Government must sign-off on the Template Sign-Off Sheet indicating how the discharge template was placed and aligned. Submit a copy of the document to the Government within one calendar day of sign-off.

3.6.3.3 Template Measurements

After the template is placed and aligned, pre-repair measurements must be taken to establish the "as-found" condition of the discharge ring. The "Center of Blade" point on the outside diametrical face of the template must be referenced to the center of blade rotation of the longest (largest diameter) blade.

The repaired finish contour of the discharge ring must be such that the profile matches the template of the original design shape, within plus or minus 0.025 inch. After the template is placed and aligned, measurements of the discharge ring must be taken, using the template as a reference, at

SECTION 48 13 13.08 26 Page 11 not less than the following elevations:

a. The blade centerline of rotation.

b. 1 inch inside the top and bottom of the band height.

c. Two intermediate points within the stainless band height. Once established, these points will not change during the repair.

3.6.3.4 Template Measurement Indexing Details

Around the circumference of the discharge ring, these measurements must be taken at each wicket gate location. The exact circumferential position of each measurement must be identified in such a manner that the measurement locations are repeatable, made at the same location each time a measurement is taken. Measurements must be taken with calibrated instruments that measure 0.010 inch without interpolation.

3.6.3.5 Template Measurement Submittal Requirements

A report of the template measurements and findings must be submitted for each of the three measurement times (a through c listed below). Title each submittal appropriately, described below. The report must be submitted within 5 days of completing the measurements. Include the locations of the discharge ring stiffener in each submission a-c below. Measurements of the circumferential band(s) must be taken at the following times:

a. Prior to any work being performed on the discharge ring an 'as found' measurement must be taken. This measurement(s) must be submitted to the Government not less than 10 days before the beginning of any metal removal. Submit Template Measurements A - Before Excavation.

Submit Notification of Template Measurements A - Before Excavation, a minimum of 24 hours prior to measurements being taken.

b. After the surface of the base metal has been repaired to establish a surface that is ¼ to 5/16 inch below the final finished surface of the discharge ring. This weld metal surface must be machined or ground to a flat surface prior to measurements being taken. This measurement must be submitted to the Government not less than 2 days before any further welding occurs. Submit Template Measurements B - Before Overlay.

Submit Notification of Template Measurements B - Before Overlay, a minimum of 24 hours prior to measurements being taken.

c. After machining of the final, finished stainless steel surface.

This measurement must be submitted to the Government not less than 5 days after machining of the surface is completed. Submit Template Measurements C - After Final Machining. Submit Notification of Template Measurements C - After Final Machining, a minimum of 24 hours prior to measurements being taken

3.6.3.6 Template Measurement Government Witness

All measurements must be witnessed and signed off by the Government and a copy of all documents submitted in the Template Sign-off Sheet. All measurements must be taken with calibrated instruments accurate to the nearest 0.010 inch unless otherwise indicated. Include calibration certification for all equipment with the report of findings.

3.6.4 Removal of Damaged Material

The following paragraphs describe the material removal requirements

SECTION 48 13 13.08 26 Page 12 specific to repairs on the discharge ring. It is not required to disturb or excavate previous stainless steel weld repairs outside the area being repaired under this contract. If stainless steel blocks (filler material) are encountered during excavation, they must be fully excavated. Otherwise, leave the previous stainless steel weld repairs in place.

3.6.4.1 48-Inch Discharge Ring Circumferential Band (1/4-inch depth)

a. The Contractor must submit a Discharge Ring Circumferential Band Metal Removal Plan. The plan must describe the detailed process, measurements, and inspections that will be performed during each unique aspect of set-up for and removal of the metal in the circumferential band. This will include, but is not limited to, plan for location of the blade 'center line of rotation'; description of the metal removal process; details of how the discharge ring template will be mounted; if one is used, the plan and detailed procedures for rotation of the machine tool; plan and method for taking of measurements. This plan must be submitted 90 days prior to mobilization to the site.

b. The Contractor must machine or grind a circumferential band 24 inches above and below (total height must be 48 inches) the horizontal repair centerline of cavitation damage. The repair centerline must be nominally the same as the blade centerline, but may be adjusted up or down as marked by the Government to account for site conditions based on cavitation damage. The minimum depth of removed material must be not less than 0.250 inch. The starting point of the 1/4 inch depth of metal removal is the new expected discharge ring surface as defined by the shaft center-of-rotation, the largest diameter runner blade, and the blade-to-discharge-ring clearance. Given that this new discharge ring surface may not match the as-found surface, there may be some machining-of-air. The template of the original design, as described in paragraph entitled, Discharge Ring Template, of this section must be used to verify the 1/4 inch depth of removed material. The boundaries of all excavations must be formed into square shoulders, normal to the original surface, with the bottom corner of the shoulder formed to a minimum radius of one sixteenth inch. The band height must not exceed 48 inches, unless so directed in writing by the Government.

3.6.5 Spot Repair of Cavitation Damage

When directed by the Government in writing, remove additional damaged material from local areas that are not conducive to removal by machining operations. This removal may be to facilitate repair of cavitation damage outside of the band area (discharge ring, hub, blades, etc), local unusually deep cavitation damage, any found cracks, or for any reason which requires local/spot repair of damage. The Government will physically outline the areas in the water passage that will require spot repair.

Working with the Contractor, a maximum depth of excavation will be agreed upon by both the Contractor and the Government, for each spot to be repaired. The description of the additional repair areas must also be noted on the Contractor created sketches depicting the area. Estimate the repair as described in paragraph "Commencement aned Estimate of Work". After the unit has been inspected and an estimate of the excavation volume required to make repairs made and accepted by the Contractor, the Government will issue a "Notice to Proceed". No excavation work or changes associated with the repair must commence until the "Notice to Proceed" is issued. The boundaries of all excavations must be formed into square shoulders, normal to the original surface, with the bottom corner of the shoulder formed to a minimum radius of one-sixteenth (0.0625) inch.