05000499/LER-2008-001, Regarding Incorrectly Stored Fuel Assembly in Spent Fuel Pool
| ML083590076 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 12/11/2008 |
| From: | Coates K South Texas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| NOC-AE-08002370 LER 08-001-00 | |
| Download: ML083590076 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4992008001R00 - NRC Website | |
text
Nuclear Operating Company South Texas Project Elkctnc Generating Station PO. Box 289 Wadsworth. Texas 77483 A/\\
December 11, 2008 NOC-AE- 08002370 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 South Texas Project Unit 2 Docket No. STN 50-499 Licensee Event Report 2008-001 Incorrectly Stored Fuel Assembly in U2 Spent Fuel Pool Pursuant to 10 CFR 50.73, the South Texas Project (STP) submits the attached Unit 2 Licensee Event Report 2-08-001 as a result of discovery that a configuration of four discharged fuel assemblies in Region 2 of the Unit 2 spent fuel pool did not meet the Region 2 checkerboard storage configuration in T.S. 5.6.1.4. The configuration was intended to meet the Region 2 RCCA Checkerboard #1 requirements of Technical Specification Figure 5.6-14, which allows only Category 9 fuel assemblies. However, a Category 11 assembly, which did not satisfy Category 9 requirements, was used in place of a Category 9 assembly.
The as-found configuration was bounded by the safety limits since the Category 11 assembly is a less reactive assembly than the Category 9 assembly intended to be used. However, the requirements of T.S. figure 5.6-14 were not met in this configuration. This event did not have an adverse effect on the health and safety of the public.
There are no commitments contained in this Licensee Event Report. Corrective actions will be processed in accordance with the STP Corrective Action Program.
If there are any questions on this submittal, please contact either.J. L. Paul at (361) 972-7344 or me at (361) 972-7849.
K. L. Coates Plant Manager STI: 32409099
NOC-AE- 08002370 Page 2 of 3 JLP
Attachment:
LER 2-08-001, Incorrectly Stored Fuel Assembly in U2 Spent Fuel Pool STI: 32409099
Cc:
(paper copy)
Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 612 East Lamar Blvd, Suite 400 Arlington, Texas 76011-4125 Richard A. Ratliff Bureau of Radiation Control Texas Department of Health 1100 West 4 9 th Street Austin, TX 78756-3189 Senior Resident Inspector U. S. Nuclear Regulatory Commission P. O. Box 289, Mail Code: MN116 Wadsworth, TX 77483 C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX.78704 NOC-AE-08002370 Page 3 of 3 (electronic copy)
A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP Mohan Thadani U. S. Nuclear Regulatory Commission Kevin Howell Catherine Callaway Jim von Suskil NRG South Texas LP J. J. Nesrsta R. K. Temple E. Alarcon K. Pollo City Public Service C. Kirksey City of Austin Jon C. Wood Cox Smith Matthews STI: 32409099
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010 (9-2007)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the diaits/characters for each block) information collection.
- 13. PAGE South Texas Unit 2 50-499 1 of 4
- 4. TITLE Incorrectly Stored Fuel Assembly in U2 Spent Fuel Pool
- 5. EVENT DATE
- 6. LER NUMBER__
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQENIA RE MNT DA YAR FACILITY NAME DOCKET NUMBER YEAR NUMBER NO.
N/A 05000 FACILITY NAME DOCKET NUMBER 10 16 2008 2008 -
01 00 12 11 2008 N/A 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
[1 20.2201(b)
El 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 5 El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
[I 50.73(a)(2)(ii)(B)
[1 50.73(a)(2)(viii)(B)
[__ 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
[I 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL [i] 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
El 50.73(a)(2)(iv)(A)
El 50.73(a)(2)(x)
El 20.2203(a)(2)(iii)
[I 50.36(c)(2)
El 50.73(a)(2)(v)(A)
[] 73.71 (a)(4)
El 20.2203(a)(2)(iv)
[I 50.46(a)(3)(ii)
El 50.73(a)(2)(v)(B)
E] 73.71 (a)(5) 0 El 20.2203(a)(2)(v)
[I 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi) 0 50.73(a)(2)(i)(B)
El 50.73(a)(2)(v)(D)
Specify in Abstract below or in NRC Form 366A
- 12. LICENSEE CONTACT FOR THIS LER FACILITY NAME TELEPHONE NUMBER (include Area Code)
Jamie L. Paul, Licensing Engineer 1 (361) 972-7344SYSTEM MANU-REPORTABLE
CAUSE
SYSTEM COMPONENT MANU-REPORTABLE
CAUSE
MPONENT FACTURER TO EPIX C
FACTURER TO EPIX
- 14. SUPPLEMENTAL REPORT EXPECTED
- 15. EXPECTED MONTH DAY YEAR SUBMISSION [E YES (If yes, complete 15. EXPECTED SUBMISSION DATE) 0 NO DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)
On October 16, 2008, while planning fuel movements in the Unit 2 spent fuel pool (SFP), a Category 11 fuel assembly was discovered in a location where only Category 9 fuel is allowed. Following this discovery, the incorrectly stored fuel was removed from its location and placed in an area of the SFP with no adjacent fuel assemblies. A Category 11 assembly is less reactive than a Category 9 assembly, and the as-found configuration was bounded by the safety analysis.
The investigation identified that the error occurred in the mapping of the SFP storage configuration, which is subsequently used to create fuel transfer forms (FTF). Both the FTF preparer and verifier performed inadequate self-checking and review. Contributing factors included a lack of detailed written guidance for performing this task and that the Reactor Engineer (RE) preparing the FTF did not realize that some fuel assemblies had decayed directly from a Category 8 to a Category 11. This resulted in fuel moves that stored a Category 11 assembly adjacent to Category 9 assemblies, which is not permitted by the Technical Specifications. A procedural guideline to control the process of developing the SFP configuration map is being developed to prevent future occurrences. In addition, all individuals who are responsible for performing this task were briefed on management expectations related to preparation, peer checking, and attention to detail. Both Unit 1 and Unit 2 SFPs were checked for a similar condition. No other occurrences of incorrectly stored fuel were identified.
NRC FORM 366 (9-2007)
PRINTED ON RECYCLED PAPER NRC FORM 366 (9-2007)
PRINTED ON RECYCLED PAPER SUMMARY OF THE EVENT Technical Specification 5.6.1.2 categorizes each fuel assembly by its reactivity based on several characteristics (initial enrichment, burnup, integrated fuel burnable absorber (IFBA) content, and decay time). Allowable storage configurations, or patterns, are then developed using the guidance in TS 5.6.1. Eleven fuel categories are defined by TS 5.6.1.2, from the highest to lowest reactivity (Category 1 to 11). The stored fuel assemblies must comply with the checkerboard requirements as specified in the TS 5.6 figures.
On 16 October, 2008, while planning fuel movements in the SFP during 2RE13, a Category 11 fuel assembly was discovered in a location where only Category 9 fuel is allowed. Following this discovery, the incorrectly stored fuel was removed from its location and placed in an area of the SFP with no adjacent fuel assemblies. Both Unit 1 and Unit 2 SFPs were checked for a similar condition, and no other occurrences of incorrectly stored fuel were found.
The investigation determined that the error occurred in the mapping of the SFP storage configuration, which is subsequently used to create fuel transfer forms. The storage configuration information available for planning displays only the maximum Category of each fuel assembly and the Reactor Engineer (RE) did not realize that some fuel assemblies had decayed directly from a Category 8 to a Category 11. This resulted in fuel moves that stored Category 9 fuel assemblies adjacent to Category 11 assemblies, which is not prescribed in the Technical Specifications.
The Fuel Transfer Form (FTF) with the incorrect information was approved and verified on 16 May, 2006 and implemented 17 May, 2006. This error was identified while reviews were being conducted for subsequent SFP moves on 16 October, 2008 during a U2 refueling outage.
Although not resulting in challenging the safety analysis, the requirements of T.S. 5.6.1.4, which prescribes allowable checkboard fuel assembly storage configurations, were not met. This
'ARC FORM 366A (0-2007)
PRINTED ON RECYCLED PAPER NIRC FORM 366A (9-2007)
PRINTED ON RECYCLED PAPERU.S. NUCLEAR REGULATORY COMMISSION (9-2007)
LICENSEE EVENT REPORT (LER)
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE YEAR I SEQUENTIAL IREVISION NUMBER NUMBER South Texas Unit 2 05000-499 2008 01 00 3
OF 4
event resulted in no personnel injuries, no offsite radiological releases, and no damage to other safety-related equipment.
E. METHOD OF DISCOVERY OF EACH COMPONENT FAILURE, SYSTEM FAILURE, OR PROCEDURAL ERROR This error was captured when a Reactor Engineer was verifying fuel transfer forms in preparation for B5B fuel transfers. During the review and discussion, the originator and reviewer identified the error that a Category 11 fuel assembly was in a Category 9 location.
- 11.
EVENT-DRIVEN INFORMATION A.
SAFETY SYSTEMS THAT RESPONDED No safety systems were required to respond during this event.
B.
DURATION OF SAFETY SYSTEM INOPERABILITY
This event did not cause the inoperability of any safety systems. The FTF with the incorrect information was approved on 16 May, 2006.. The FTF was implemented by placing the Category 11 fuel assembly in a Category 9 location on 17 May, 2006. The incorrect SFP configuration was discovered on. 16 October, 2008 and relocated to an appropriate location on the same day.
C.
SAFETY CONSEQUENCES AND IMPLICATIONS OF THE EVENT Category 11 fuel is less reactive than a Category 9 fuel. Therefore, placing a Category 11 fuel in a Category 9 location did not involve a challenge to any design criteria or safety barrier. In addition, the safety analysis accounts for a misplaced fuel assembly in the SFP. The analysis assumes a fresh assembly of 4.95 weight percent (w/o) is inserted into a rodded position of the checkerboard configuration where the Category 11 assembly resided. By maintaining the SFP boron concentration above the Technical Specification required value, the design criteria for maintaining Keff < 0.95 was met with the misplaced assembly. Hence, the condition did not constitute an unanalyzed condition.
This event resulted in no personnel injuries, no offsite radiological releases, and no damage to other safety-related equipment.
III. CAUSE OF THE EVENT
The root cause of the error was that both the fuel transfer form preparer and verifier performed inadequate self-checking and review. One contributing factor was a lack of robust guidelines for planning and verification of the SFP configuration and its compliance with Technical Specification requirements which contributed to the human performance error. Another contributing factor was
'JRC FORM 366A (9-7007)
PRINTED ON RECYCLED PAPER
'4RC FORM 366A (9-2007)
PRINTED ON RECYCLED PAPERU.S. NUCLEAR REGULATORY COMMISSION (9-2007)
LICENSEE EVENT REPORT (LER)
- 1. FACILITY NAME
- 2. DOCKET
- 6. LER NUMBER
- 3. PAGE YEAR SEQUENTIAL I REVISION A
NUMBER NUMBER South Texas Unit 2 05000-499 2008 01 00 4
OF 4
determined to be the organization and format of the SFP configuration map used in planning fuel moves which only identified the highest fuel Category and did not identify any skipped Categories.
IV. CORRECTIVE ACTIONS
" Following discovery of the non-conforming condition, a fuel transfer form was prepared and the incorrectly stored fuel assembly was removed and put into a cell location that met the T.S.
requirements.
" All individuals who are trained on this Qualification (#9334) were briefed on management expectations related to preparation of Fuel Transfer Forms (FIF), peer checking, and paying attention to detail.
" Both Unit 1 and Unit 2 SFPs were checked for a similar condition. No other occurrences of incorrectly stored fuel assemblies were found.
" Existing procedural guideline will be revised to provide additional controls for developing SFP configuration maps and Fuel transfer Forms (FTF). This guidance will also include indicating skipped fuel Categories in addition to the highest fuel Category on the SFP map.
V.
PREVIOUS SIMILAR EVENTS
A history review of condition reports did not identify any previous similar events at STP.
VI.
ADDITIONAL INFORMATION
None.
'JAC FORM 366A 19-2007)
PRINTED ON RECYCLED PAPER
'4RC FORM 366A (9-2007)
PRINTED ON RECYCLED PAPER