L-PI-11-039, Response to Violation in Nuclear Regulatory Commission (NRC) Exercise of Enforcement Discretion Inspection Report 05000282/2011008; 05000306/2011008 (EA-11-029)
| ML111110540 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 04/20/2011 |
| From: | Schimmel M Northern States Power Co, Xcel Energy |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| EA-11-029, IR-11-008, L-PI-11-039 | |
| Download: ML111110540 (2) | |
Text
@ Xcel Energye APR 2 0 2011 U S Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Units 1 and 2 Dockets 50-282 and 50-306 License Nos. DPR-42 and DPR-60 Response to Violation in Nuclear Requlatow Commission (NRC) Exercise of Enforcement Discretion lns~ection Re~ort 05000282/2011008; 05000306/2011008 (EA-1 1-029)
Reference:
1 Memorandum to Gary L, Shear, Deputy Director Division of Reactor Projects Region Ill, from John R. Jolicoeur, Acting Deputy Director Division of Policy and Rulemaking, Office of Nuclear Reactor Regulation (NRR), "Task Interface Agreement (TIA) - Evaluation of Flooding Licensing Basis at Prairie Island Nuclear Generating Plant (PINGP) (TIA 201 1 -007), dated January 28, 201 1 (Accession Number MLI 10240359).
- 2. Letter from NRC to Mr. Mark A. Schimmel, "Prairie Island Nuclear Generating Plant, Units 1 and 2, Exercise of Enforcement Discretion 05000282/2011008; 05000306/2011008", dated March 22,201 1 (Accession Number MLI 10820201).
In Reference 2, the NRC closed the unresolved item (URI 050002821201001 1-01;0500030612010011-01) and documented a violation of 10 CFR 50, Appendix B, Criterion Ill, "Design Control," for the failure to protect safety-related equipment from the effects of internal flooding. Reference 2 also requested that Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM") provide a response within 30 days with the actions taken or planned to resolve the non-compliance with regulations.
The non-compliance with regulations was resolved by changes to the facility made to ensure adequate flooding protection. The following flood mitigating features are credited:
Flood barriers to protect the Dl, D2, D5, and D6 emergency diesel generators.
Access covers in the auxiliary feedwater (AFW) rooms were fastened to prevent differential pressure from opening them.
Roll-up doors at the east and west ends of the turbine building were blocked open.
Security barriers at each roll-up door were opened or modified 171 7 Wakonade Drive East Welch, Minnesota 55089-9642 Telephone: 651.388.1 121
Document Control Desk Page 2 Safeguards battery room doors and door seals were credited to minimize flow into the rooms around door gaps on the high energy line break (WELB) unit and allow flow out on the non-HELB unit.
AFW pump room doors and door seals were credited to prevent water flow into the room around door gaps.
NSPM believed that the licensing and design basis for the plant did not require that the impact of consequential flooding following a HELB event be considered when determining whether the HELB resulted in a loss of safety function of equipment required to mitigate the consequences of a HELB event. However, the NRC provided clarification of the flooding analysis requirements in Reference 1, Task Interface Agreement (TIA) 201 1-087, which concluded:
"...the NRR staff concludes that if a ruptured high energy line can whip and strike another fluid-filled line which meets the criteria for being ruptured by a whipping high energy line, the second (target) pipe must also be assumed to rupture, There is no basis for not including the water contribution from the target pipe rupture in the facility's flooding analysis. Therefore, the NRR staff's position is that the fluid from the target pipe must also be included in the flooding analysis at PINGP. Further, if the HELB can also result in actuation of the fire sprinkler system, then the water from that system must also be included in the flooding analysis at PINGP."
The changes to facilities listed above and the licensing basis provided via TIA 201 1-07 have been incorporated into the Updated Safety Analysis Report.
Summary of Commitments This letter contains no new commitments and no revisions to existing commitments.
Mark A. Schimmel Site Vice President, Prairie Island Nuclear Generating Plant Northern States Power Company - Minnesota cc:
Administrator, Region ill, USNRC Project Manager, PINGP, USNRC Resident Inspector, PINGP, USNRC