AMD-SS23-07 - Thermal Column SSN.pdf

Sources Sought derived from Statement of Work

The Government is seeking potential sources with demonstrated capability in the designated areas outlined in this document. Interested parties should fully read this notice and respond with their capabilities and the ability to meet the mechanical complexity, as well as on the nuclear (waste) aspects, associated with these tasks.

Statement of Work

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.

1. 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.

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

3. 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

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 and the NCNR has decided that the time has come to procure all the tools and procedures necessary to be able to replace the TCT.

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 support from the outside to perform the necessary specialized engineering 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 of the extent to which the walls, ceiling, and floor of the tunnel cavity in which the TCT is located have maintained their dimensional and positional stability over time. 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.

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.

Access to Government Supplied Information.

Contractor will have access to all Government drawings that relate to the thermal column and its environment.

Typical Deliverables

1. All Reports, Plans, Designs, and Drawings (to be approved by COR)

2. Identification of TCT-Removal/Installation (sub-)contract workforce (to be deployed for review of engineered product as well as the actual mobilization efforts).

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

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

3. Review report of Procedures and Tooling proposed by NIST (for feasibility).

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

5. 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.

6. 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.

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

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

9. Engineering documents for toolset needed to perform TCT removal procedure.

9.1. 3D models.

9.2. 2D drawings.

9.3. Procurements (i.e., camera).

9.4. Report based on review by identified Contract Workforce and NIST.

9.5. All Reports provided in MS Word and pdf.

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

10. Manufactured toolset.

10.1. Plan on how to identify suitable machine shop.

10.2. Supervision plan for machine shop QA.

11. Extraction and insertion procedures.

11.1. Report of Review by Contract Workforce and NIST.

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

11.3. Final Implementation Process Report for Actual Project

12. Timeline.

12.1. Kick-Off Meeting

12.2. 60% Design Meeting

12.3. 100% Design Meeting

12.4. FAT Trial(s)

12.5. Final Mobilization

13. Delivery of toolset/procedures.

14. Mobilization of (sub-)contract workforce.

15. Execution of procedures using engineered tools.

16. Final Step: TCT is transferred to its final resting place in abandoned truck bay and Thermal Column is rebuilt as a restored facility.

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

NOTE

The Procedure and Tooling are not submitted as part of the sources-sought notice. The Procedure and Tooling in question will not be considered a specification: they will only serve to document the engineering effort undertaken by NIST during the time TCT replacement was an active topic of discussion at NIST. The Procedure and Tooling (concept) designs will be shared at the time the Request for Proposal for this requirement is published. Since the Procedure and Tooling in question will not be considered a specification, a successful bidder is free to significantly deviate from the information contained in them and still meet the requirements of the contract.