Attachment A SOW TCT Replacements.docx

Statement of Work Thermal Column Tank (TCT) Replacement

I. Background

The National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR) owns and operates a 20 MW Test Reactor. This reactor is known by and licensed under the initialism NBSR, which stands for National Bureau of Standards (NBS) Reactor. NBS changed its name to NIST in 1988. The neutron radiation produced by the NBSR is deployed for the pursuit of a large variety of materials science and physics research efforts. The NBSR is located on the NIST campus in Gaithersburg, Maryland, USA. First criticality of the NBSR occurred in 1968.

The NBSR is a heavy water (D2O) cooled and moderated reactor. The D2O inventory is contained in an enclosed process system that is blanketed by high purity helium gas to insulate the D2O from environmental air.

The reactor is contained in an 84” diameter aluminum vessel. The reactor vessel is part of a pump process system that provides the D2O flow that is necessary to cool the reactor when operating. A biological (radiation) shield consisting of a heavy concrete and steel structure surrounds the reactor vessel.

An experimental facility, called the Thermal column is located immediately south of the reactor vessel. The facility resides in a tunnel of roughly 60x60 sq. inch cross section and reaches from the outside of the biological shield to the reactor vessel. Neutrons emanating from the reactor flow through the facility in the southern direction. The thermal column has three components, presented here in order of proximity to the reactor vessel.

The Thermal Column Tank (TCT). On the north end it is a tank filled with recirculating D2O. On the south end it incorporates an 8-inch-thick bismuth slab, which is cooled by the recirculating water.

1. A stack of graphite of approximately 60x60 sq. inch. The stack is 40 inch thick in the direction of the neutron flux.

2. A composite shield that acts as a door to close off the facility when not in use. The door is equipped with steel wheels and can be moved on a track

II. Thermal Column Tank Problems and Relationship with other Procurements.

The original TCT was built around 1966 and inserted into the reactor before its first criticality in 1968. In FY 2000 a leak was detected at the bottom of the TCT on the south face at the location of a weld repair (hailing from 1966). The D2O flow was lowered from 40 GPM to 5 GPM after it was determined that this flow was sufficient to keep the bismuth from becoming dangerously warm. Also, the D2O was replaced with regular water (H2O). Eventually the tank was put under a very slight vacuum (a couple of inches of water column). Together, these measures effectively stopped the leak.

During the period that the NCNR tried to fix the leak, a replacement TCT was procured to be ready for if the leak could no longer be contained. The replacement TCT is in the possession of the NCNR since FY2004.

In FY 2019 it was detected that a new H2O leak had developed. Careful analysis demonstrated that the new leak is located on the reactor side (north side) of the TCT. The leak also appears to be growing in size with time. So now, in addition to having procured the replacement TCT the time has come to procure all the tools and procedures necessary to be able to replace the TCT on as short a notice as possible, when the need arises. This does not happen until the leak becomes unmanageable. However, we are aware that this can happen any day, because we cannot predict the future.

The H2O that is leaking mixes with CO2 that is present in between the TCT and the Reactor Vessel. This makes for a slightly acidic solution known as carbonic acid, which is corrosive to many metals.

To the NCNR and by extension NIST a suddenly inoperable Thermal Column Tank presents a programmatic risk of about $100K per lost day of operation.

III. Project Description

In June 2019 the NCNR made the decision to attempt to procure engineering services to provide tooling and procedures, such that the present TCT can be replaced by the new TCT that is already in its possession.

Over the past several years, engineers at the NCNR have spent considerable effort analyzing the feasibility of such a project and the NCNR has convinced itself by developing a high level TCT exchange procedure that such a project is indeed feasible, provided the NCNR can count on specialized support from the outside to create fast turn-around engineering solutions and the capability to mobilize specialized technical personnel to perform the actual TCT exchange.

Whether or not this project can be successful depends on whether the TCT can be extracted from its current position. This is a function the long-term (historical) dimensional stability of the walls of the tunnel in which the TCT is located. NIST has contracted for a Laser Scan to be performed to accurately map the interior of the tunnel. This work has not yet been completed. It has been determined, however, that the risk of an uncontrollable failure of the present TCT is so high that steps must be taken now to prepare for a TCT exchange that can be executed without further delay when such would become necessary. In other words: the assumption is made that on its way out the tunnel, the TCT will clear the floor, ceiling and walls without any need for modifications, i.e., the TCT can be removed and replaced. This is by no means guaranteed, making this a high-risk procurement.

It is estimated that a best effort to that effect will be undertaken to do so regardless of the occurrence of an actual TCT failure.

IV. Performance specification

Supply all labor and materials to prepare for and execute the replacement of the NBSR TCT with a new one (new TCT supplied by NIST). In this specification it is assumed that the TCT does not interfere with the walls, ceiling, and floor of the TCT tunnel.

V. Government Responsibilities

1.1. Provide pictures, drawings, and information pertinent to completing this task.

1.2. Provide access to NIST and the work area.

1.3. Provide NCNR Radiation Safety Training (1/2-day class) to individuals working in radiological control areas (RCA’s) when applicable.

1.4. NIST Health Physics will support contractor’s health physics personnel by providing Personal Protective Equipment (PPE) (i.e., coverall, gloves, boots, hoods, dosimeters, etc.).

1.5. The reactor instrument shop and engineering group will provide power necessary for the equipment used to complete this task.

1.6. Summary of the local radiation levels on the components and at the immediate location where the task will be completed.

1.7. Summary of the local radiation levels at the general area upon completion of the task.

1.8. Provide camera, review of photos and release of photos (*pdf file format) for taking pictures of the progression and completion of the task.

1.9. Review and approve contractor’s proposed method for completing the task.

1.10. Reactor Operations and Engineering will remove and reinstall the graphite and other components for access to the TCT.

1.11. Reactor Operations and Engineering to support lifting/rigging and associated equipment:

1.11.1. C100 Overhead crane with 15-ton capacity.

1.11.2. C200 overhead crane with 20-ton capacity.

VI. Period of performance

Eighteen (18) months from award of contract.

VII. Place of Delivery

1. Free on Board (FOB) to NIST Gaithersburg

2. Items must be packaged in a way that are appropriately protected from the elements during transit.

3. Delivery of components must be scheduled such that they arrive at NIST Gaithersburg between the hours of 7:00 AM and 3:00 PM EST on a working day unless otherwise agreed upon in advance.

4. Contractor shall notify the COR or designee of projected arrival times of deliveries at least 2 working days prior to arrival. Notification shall include date and approximate time of arrival, name of shipping company, and name and citizenship of driver(s). Provided the driver is a U.S. citizen a minimum of one day is needed to register drivers with NIST security.

5. Contractor shall notify the COR or designee of any radioactive material that will be sent to NIST Gaithersburg in support of this Task at least 7 working days in advance of the desired shipment date. No radioactive material shall be shipped to NIST Gaithersburg without the advanced approval of the COR or designee.

VIII. Deliverables

1. All Reports, Plans, Designs, and Drawings (to be approved by COR) Identification of TCT-Removal/Installation (sub-)contract workforce (to be deployed for review of engineered product as well as the actual mobilization efforts).

Report demonstrating the contract workforce is familiar with ALARA considerations to minimize exposure to personnel.

Plan that shows preparedness for remote supervision by NIST Health Physics.

Review report of Procedure proposed by NIST (for feasibility).

Result of 3D modeling effort of thermal column area and associated inserts (TCT, graphite, door).

Thermal Column Tank Removal Procedure under the assumption that the TCT will clear the floor, ceiling, and walls of the tunnel without the need for tunnel modifications (whether this is the case can be determined from the results of a Laser Scan of the TCT cavity that has been procured under separate contract). Note that the result of the Laser Scan has no influence on the design of this Procedure.

Reports on practice runs of a TCT replacement performed on the premises of the contractor (by the contractor). Note: Government Staff may want to witness practice runs on reasonably timed requests.

Floor loading study allowing optimization of tooling weight in a trade-off with tooling shielding function.

Shielding calculations (there will be input from NIST on source strength of the inside components of the Thermal Column).

Engineering document for toolset needed to perform TCT removal procedure.

3D models.

2D drawings.

Procurements (i.e., camera).

Report based on review by identified Contract Workforce and NIST.

All Reports provided in MS Word and pdf.

All Design documents provided in AutoCAD, or SolidWorks format and pdf.

Manufactured toolset.

Plan on how to identify suitable machine shop.

Supervision plan for machine shop QA.

Extraction and insertion procedures.

Report of Review by Contract Workforce and NIST.

Report of Practice runs on mockup(s) (FAT Trials).

Final Implementation Process Report for Actual Project Meetings: Conduct biweekly status and planning meetings (kickoff meeting being the first one) from award of contract to completion of the contract. These should be virtual meetings setup by the contractor. NIST prefers using Microsoft Teams. Contractor must send written summaries (*.pdf format) after each meeting to NIST for review and concurrence. Meeting schedule may be modified as necessary by mutual agreement between the contractor and the government’s technical representative.

Timeline.

Kick-Off Meeting Biweekly Status Meetings including 60% and 100% Design Meetings FAT Trial(s) Final Mobilization Delivery of toolset/procedures.

Mobilization of (sub-)contract workforce.

Execution of procedures using engineered tools.

Final Step: Remove old TCT, transfer it to onsite storage area and install new TCT.

This list of deliverables has been generated from a conceptual procedure (Attachment 1) that has been developed by NIST. The conceptual procedure appears (however, is not) very detailed. The function of the conceptual procedure is to convey conditions one is likely to encounter at the place of performance (NIST Center for Neutron Research).

The conceptual procedure refers to numbered tools that will have to be developed by the contractor (subject to contractor review and discussion with the Government). An associated PowerPoint document (Attachment 2) is supplied where these tools are further detailed albeit by no means to the level of detail that makes them immediately manufacturable.

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