05000368/LER-2007-001, Re Completion of a Plant Shutdown Required by Technical Specifications Because a Control Element Assembly Dropped Into the Core as a Result of a Failed Upper Gripper Coil
| ML070930417 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 03/26/2006 |
| From: | James D Entergy Operations |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| 2CAN030703 LER 07-001-00 | |
| Download: ML070930417 (8) | |
| 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 |
| 3682007001R00 - NRC Website | |
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"'Entergy Entergy Operations, Inc.
1448 S.R. 333 Russellville, AR 72802 Tel 479-858-4619 Dale E. James Manager, Licensing - ANO 2CAN030703 March 26, 200'I U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001
Subject:
Licensee Event Report 50-368/2007-001-00 Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NFP-6
Dear Sir or Madam:
In accordance with 1 OCFR5O.73(a)(2)(i)(A), enclosed is the subject report concerning completion of a plant shutdown required by Technical Specifications.
Commitments contained in this submittal are documented in the attachment.
Sincerely, Dale E. / mes Manage(, Licensing DEJ/rs Enclosure j~69~9~
2CAN030703 Page 2 cc:
Dr. Bruce S. Mallett Regional Administrator U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-8064 NRC Senior Resident Inspector Arkansas Nuclear One P.O. Box 310 London, AR 72847 Institute of Nuclear Power Operations 700 Galleria Parkway Atlanta, GA 30339-5957 LEREvents@inpo.org
NRC FORM,366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007 (6-2004)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the diaits/characters for each block) information collection.
- 3. PAGE Arkansas Nuclear One - Unit 2 050003681 1 OF 4
- 4. TITLE Completion of a Plant Shutdown Required by Technical Specifications Because a Control Element Assembly Dropped Into the Core as a Result of a Failed Upper Gripper Coil
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED MONTH DAY YEAR YEAR SEQUENTIAL REV MONTH DAY YEAR FACILITY NAME DOCKET NUMBER NUMBER NO.
05000 I
I05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)
El 20.2201(b)
El 20.2203(a)(3)(i)
[] 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii)
El 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
E] 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
El 50.73(a)(2)(viii)(B)
[I 20.2203(a)(2)(i)
[I 50.36(c)(1)(i)(A)
[] 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
El 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)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
El 73.71(a)(4)
El 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii)
[1 50.73(a)(2)(v)(B)
El 73.71(a)(5)
[I 20.2203(a)(2)(v) 0 50.73(a)(2)(i)(A)
El 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi)
El 50.73(a)(2)(i)(B)
[E 50.73(a)(2)(v)(D)
Specify in Abstract below or in (If more space is required, use additional copies of (If more space is required, use additional copies of (If more space is required, use additional copies of NRC Form 366A)
E.
Safety Significance
CEAs misaligned from their group position, specifically dropped CEAs, affect the power distribution within the core. In the case where a CEA which is normally fully withdrawn is dropped, power in the vicinity of the dropped CEA is reduced to a very low value. If reactor power remains substantially unaffected, power density increases in the rest of the core.
A dropped CEA event has been previously analyzed and specific compensatory actions are prescribed in the licensing basis documents.
Since the compensatory actions contained in the Technical Specifications and Core Operating Limits Report were complied with during this event, it is considered to be of minimal safety significance.
F.
Basis for Reportability 10CFR50.72(b)(2)(i) requires an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> notification regarding the initiation of any nuclear plant shutdown required by the plant's Technical Specifications whereas 10CFR 50.73(a)(2)(i)(A) requires a 60 day report regarding the completion of any nuclear plant shutdown required by the plant's Technical Specifications.
All required reports were made, as required by regulation.
G.
Additional Information
A similar previous event in which a failed upper gripper coil resulted in a dropped CEA was reported in Licensee Event Report 2-1984-26-00. There were no actions to prevent recurrence taken with respect to this event. However, because it was believed that high voltage events during the early years of operation may have degraded the coils, all of the CEA upper gripper coils were replaced with coils containing different potting material which had better heat transfer characteristics between 1983 and 1988. Most of the coils (65 of 81), including that of CEA 35, were replaced in 1988. The upper gripper coil failure discussed in this report is the first involving one of the replacement coils.
Energy Industry Identification System (EIIS) codes are identified in the text as [XX].
Attachment 2CAN030703 List of Regulatory Commitments
Attachment to 2CAN030703 Page 1 of 1 List of Regulatory Commitments The following table identifies those actions committed to by Entergy in this document. Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.
COMMITMENT
TYPE SCHEDULED (Check One)
COMPLETION DATE (If Required)
ONE TIME CONTINUING ACTION COMPLIANCE Develop a system monitoring plan to include specific acceptance and X
replacement criteria for CEA coil trace reviews.
Remove additional upper gripper coils during the next refueling outage (2R19) to gather information to X
finalize the root cause of the CEA 35 coil failure.
The upper gripper coils of the remaining CEAs in the sub-group containing CEA 35 will be replaced X
during the next refueling outage.
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