ML22235A117
| ML22235A117 | |
| Person / Time | |
|---|---|
| Site: | National Bureau of Standards Reactor |
| Issue date: | 08/23/2022 |
| From: | Newton T US Dept of Commerce, National Institute of Standards & Technology (NIST) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML22235A117 (23) | |
Text
NISI I NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY U.S. DEPARTMENT OF COMMERCE August 23, 2022 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Docket Number 50-184 Confirmatory Order
Dear Sirs/Madams:
Attached please find a draft of a proposed presentation on the February 3, 2021 , NBSR event for NRC review. This is intended to be presented at the October meeting of the National Organization of Test, Research, and Training Reactors, and satisfies the requirement of the Confirmatory Order of August 1, 2022, section V. 7 .d.
Deputy Director Chief, Reactor Operations and Engineering NIST Center for Neutron Research N,s1
N ** +4 C Neutron enter for Research The NCNR Fuel Failure Event: Recovery and Corrective Actions Tom Newton Deputy Director Chief of Reactor Operations and Engineering
2 NCNR NCNR In s tr u m e n t
- One of three major Lay out neutron Science 30mSANS Centers in the US
- Supports > 3000 research participants annually BT9 VSANS MACSII BTT
- Neutrons supplied by 3-AXIS 20 MW reactor, the NBSR
- Reactor operates on a 38 day fuel cycle NIOF
Cut-away View of the NBSR Core Top Grid Plate Cd Shim Safety Arms (4) Fuel Elements (30)
Fuel Plates Reactor Vessel Radial Beam Tubes (9) Liquid Hydrogen Cold Neutron Source Split Core:
18-cm Unfueled Bottom Grid Plate Gap - Flux Trap D2O Primary Primary Outlet (2)
Inlet Plenums Thermal Shield
Refueling January 4, 2021
- Routine refueling performed, with latching and latch checks
- After-the-event review showed these checks were done incorrectly.
- 2nd cycle element was not latched.
- Startup was delayed ~1 month because of COVID concerns.
- Routine (daily) starting and stopping of primary pumps pushed the element into an area outside of flow.
- Not detected by any instruments prior to startup.
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6 Video Surveillance of Core Began 2/23/21 Lower grid plate, near position J-7 Bottom of failed fuel element prior to removal from the core on August 5
7 Safety Limit 6.6 Required Actions February video 6.6.1 Actions to Be Taken in the Event the Safety Limit is Exceeded surveillance showed (1) The reactor shall be shutdown and reactor operation s shall not be resumed single element out of until authorized by the NRC.
position with apparent (2) An immediate notificatio n of the occurrence shall be made to the Chief, fuel damage.
Reactor Operation s and Engineeri ng and the Chief, Reactor Operations.
The Chief, Reactor Operation s and Engineeri ng shall inform the NCNR Concluded that 450oC director.
fuel safety limit had (3) Reports shall be made to the NRC in accordanc e with the specifications of Section 6.7.2. A written report shall include an analysis of the causes and been exceeded, report extent of possible resultant damage, efficacy of corrective action, and recommen dations for measures to prevent or reduce the probability of to NRC in accordance recurrence. The report shall be prepared by the Chief, Reactor Operations with TS 6.6.1 and Engineeri ng and submitted to the SEC for review. The SEC shall review the report and submit it to the Director, NIST Center for Neutron Research director for approval. The Director shall then submit the report to the NRC.
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8 Initial Root Cause Investigation 2021 2 2 Internal Technical Working Group (TWG) formed to investigate root cause May 13: TWG report complete; letter to Root Cause Invest NRC reporting inadequacies in:
igation of Fe br ua ry 20 21 Fu el Failure Training and procedures in fuel latching NCNR Technical W or kin g Group Procedural compliance Management oversight April 30 , 20 21 June 3 follow-up: finding that element could inadvertently be unlatched by use of refueling tool without rotational force Page lof2 7
9 Safety V Evaluation a a 0 Committee Co e (SEC) C Investigation a 0 2021 2 2 SEC Subcommittee formed to FINAL Report SEC Sub com mit tee Rep ort:
investigate response, root cause Rev iew of the NCNR Eve nt Res pon se and Tec hni cal Wo rkin g Gro up Roo t Cau se Analysis and Cor rec tive Act ion Pla n review and corrective actions Sub mit ted to NCN R Dir ect or Two additional root causes:
Au gus t 12, 202 1 Fro m the Saf ety E11 aluation Co mm itte E11ent Re spo nse and e (SEC) Sub com mit Cor rec ti11 e Ac tion tee :
Lack of change management program Culture of complacency 24 recommended corrective actions Sub com mit tee Me mb and program improvements Elizabeth Mackey, NIS ers:
T Chief Safety offi cer Donald Pierce, NIST, , SEC Vice Chair NCNR Engineer, SEC Am ber Joh nso n, Uni Chair 11ersity of Maryland, nm oth y Bar11it.Skie, SEC NIST, NCNR Health Phy Me mb er Jam es Adams, NIST, sicist, SEC Me mb er Chief Radiation Phy sics Di11ision SEC SUbcommtttee RevieW
10
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Corrective C Actions --
- - Management Change management:
New Aging Reactor Management program Organizational realignment, including additional training shift Procedure overhaul with compliance audits Problem Identification and Resolution System Review Team Review system changes Corrective Action Plan under development Integrated with other programs: trouble tickets, engineering changes, audits Tiered with safety significance Continuous improvement All NCNR-ROE staff involved in detailed corrective actions implementation and recovery tasks.
Annual benchmarking with other facilities
11 Safety culture C changes Plan of the day meeting INPD Do cum en t Safety minute every day Weekly discussion of selected safety event, related INPO 12 -01 2 December 2012 to INPO 12-012, Traits of a Healthy Nuclear Safety Culture Reorganization of safety structure Traits o f a Healthy N u c le a r Safety Culture training for all personnel Safety Culture (ROE/HP)
Observation program - including all levels of NCNR management Employee Engagement - Safety recognition OPEN DISTRIBUTIO N
12 Safety culture corrective e actions act*o s 3rd party annual safety culture assessment 3rd party nuclear program assessment:
- 1. Problem Identification and Resolution
- 2. Event Root Cause
- 3. Training
- 4. Procedures
- 5. Safety Assessment Committee
- 6. Safety Evaluation Committee independence and effective oversight Safety Culture Monitoring Panel Leadership Accountability Safety Evaluation Committee changes Safety culture training for leadership (INPO 12-012)
Management performance appraisal to include safety culture
13 Corrective C Actions C 0 --
- Training a
Proficiency training Qualification for fuel movements Programs rewritten for better knowledge transfer Plan for more frequent staff attrition Development of standards for supervisors Qualification and oversight training Periodic management reviews of program
14 Corrective C Actions C 0 --
- Procedures 0
Personnel adherence Safety more integrated into procedures Revision to INPO 11-003 169 procedures were revised as condition for startup Rewrite fueling procedures Capture details Redundant rotation check New procedures Visual checks No contact with fuel head during and after visual check
15 Corrective C Actions --
- Equipment New rotation check gauge New visual (video) checks Discontinue use of height checks NI noise gate Gurgen presentation
16 NCNR C interactions with NRC C
2021 February 8: NRC Special Inspection Team begins February - May: Written reports on event, exceeding safety limit, and findings of inadequacies October 1: Root causes, planned corrective actions and request for permission to restart December 23: LAR submitted to require both rotation and visual latch checks in technical specifications 2022 March 16: SIT report issued; escalated enforcement; NCNR enters Alternate Dispute Resolution July 21: LAR approved August 1: NRC issues Confirmatory Order and Supplemental Inspection Plan
17 NRC Findings gs
- 1. TS 2.1*: Safety limit violation (fuel cladding temperature exceeding 842 oF)
- 2. TS 3.1.3**: All grid positions not filled with full length elements
- 3. TS 6.4**: Procedure inadequacies - fuel handling
- 4. TS 6.4: Procedure inadequacies - startup monitoring for abnormal indications
- 5. TS 6.4: Procedure inadequacies - emergency response delays
- 6. TS 3.9.2.1**: elements not properly verified to be latched in the core grid.
- 7. Inadequate 50.59 review: changes to refueling tools
- 3/5/21 NCNR Report to NRC
- 5/13/21 NCNR Report to NRC
Page 15 of 56 18 Primary y Cleanup Section VI: Proee-ss: Room HS 4 and Gf>nenl BS Pr I a Filter elements installed in all 30 core positions Each and all (4) primary pumps run Mechanical agitation: use of ultrasonics in low flow areas.
Chemical agitation: insertion of CO2 into pump discharge piping.
Analysis shows that major release of fission products from remaining debris is not credible.
Complete cleanup will require long term effort, including component replacement. (1.4.b 50U!Ce overlay imagufHS 3, HS 4 , HS 7, H:S S, and ~ 1.11,ot spots)
19 Recovery 0 e y timeline Fall 2021: All fuel elements removed from core, including damaged element February 2022: Reactor vessel cleanup complete March 2022: Primary system cleanup using filter elements Most remaining fuel elements contained debris Startup core: Celikten presentation August 2022: Startup plan submitted to NRC Vessel cleanup February 2022
20 Conclusion Co c us*
Feb. 3, 2021 event was unprecedented in recent U.S. research reactor history.
NIST is committed to long term major corrective actions as outlined in the NRC Confirmatory Order.
Restart plan submitted to NRC outlining special startup preparations and precautions.
NRC Special Inspection ongoing.
Frequent and open communications with NRC is key to recovery and restart.
21 Backup slides
22 Latching video
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