1. 5/19/2015 Segmentation of the Legacy C Area Disassembly Spent Fuel Pool Prepared by: Jon Guy, N&CSE Spent Fuel Project Lead UNCLASSIFIED DOES NOT CONTAIN UNCLASSIFIED CONTROLLED NUCLEAR INFORMATION DC & Reviewing Official: Les Yerger/ L-Area N&CSE. Date: 4/09/2012. Guidance: IG-SR-03, 2/04

2. 5/19/2015 C Reactor Area Background The C Reactor Facility began operation in early 1955 for the production of nuclear materials. C Reactor was retired from operation in 1985 with no capability for restart.

3. 5/19/2015 C Area Current Mission Tritium contaminated moderator is stored inside the C Reactor Facility Irradiated Stainless Steel and Aluminum reactor components are stored in the Reactor Tank and Disassembly Spent Fuel Pool(~3.5 million Gallon) The C Area 105 Building and specific peripheral buildings are considered to be in a Surveillance and Maintenance Mode awaiting closure by Area Completion Projects

4. 5/19/2015 C Area Safety Basis C Area is considered a Hazard Category 2 facility. The current Safety Document is a Basis for Interim Operation(BIO) and a TSR Major hazards: – Legacy reactor contaminated moderator storage (Tritium) – Activated Reactor Components (Stainless Steel and Aluminum) – A small fissile material exist in the dirt layer at bottom of the Disassembly Spent Fuel Pool

5. C Reactor Area Safety Basis C-Area – Not continuously manned – Surveillances are completed quarterly – Disassembly Spent Fuel Pool locked with limited access permitted. Safety Analysis for C Reactor very conservative – No return on Investment – No real need identified for new approach 5/19/2015

6. Why Safety Basis is being revised Site-wide footprint reduction tied to elimination of the potential ground water release from C Area Disassembly Basin. Area Completion Projects would be permitted to evaporate the basin water and grout activated scrap “in place” within the Disassembly Basin. Segmentation of the Disassembly Basin and categorization as a Radiological Facility eases requirements in accordance with the reduced risk. Return on Investment significant for this project. – Reduce engineering, maintenance and construction cost during evaporation and grouting.

7. 5/19/2015 C Reactor Safety Basis Revision Plan C Reactor Safety Basis – Removed reference to the Disassembly Spent Fuel pool and any associated controls – Acknowledged that a new Auditable Safety Analysis would be the Safety Basis for the segmented Disassembly Basin.

8. 5/19/2015 C Reactor BIO Revision Plan Prepare a Hazard Determination document to support segmentation and downgrade – Activated Reactor components (Example Co 60) – Source Term of water and legacy dirt layer – Additional source terms included in proposed segment. (example: Legacy Spent Fuel Pool Sand Filters Prepare an Auditable Safety Analysis for the segmented C- Area Disassembly Spent Fuel pool – Auditable Safety Analysis is the safety basis document for facilities categorized as Radiological. – Also act as final Hazard Determination Approve a Downgrade of the new Segment from Hazard Cat 2 to radiological

9. 5/19/2015 Main Issues for Downgrade Activated Stainless Steel can contain higher than Hazard Cat 3 quantities of some isotopes. – Solid material not releasable from storage location – Grout addition maintains water shielding over activated material

10. Main Issues for Downgrade Fissile material in dirt layer at the bottom of basin – New Nuclear Criticality Safety Analysis used to show criticality event not credible Hydrogen generation due to legacy reactor components interaction with grout – Engineering analysis performed to show not a credible event 5/19/2015

11. Main Issues for Downgrade Actual physical separation of the new segment from the rest of the C Reactor facility. – The fuel transfer canal between the spent fuel pool and reactor area remained open – Disassembly Final Storage area had open weirs that needed to be sealed. – There was no physical barrier separating the new segment outside the building. 5/19/2015

12. Major Implementation Items for Segmentation Fuel Transfer canal grouted closed Final Storage grouted closed Activated reactor components were located and lowered to maintain water shielding A new fence will be installed to establish the new segment.

13. 5/19/2015 Before and After C Area Final Storage Before After

14. Before and After Fuel Transfer Canal 5/19/2015 BeforeAfter

15. Activated Scrap after Lowering 5/19/2015

16. Status The BIO has been revised and Approved The Auditable Safety Analysis and Segment down grade are approved All implementation items are complete. De-watering and grouting of the Disassembly Spent Fuel pool is ongoing.

17. Questions: 5/19/2015