IR 05000353/2011009

EA-11-221 Limerick - Final Significance Determination for a White Finding with Assessment Follow-Up and Notice of Violation (NRC Inspection Report No. 05000353/2011009)

ML113410132
Person / Time
Site:	Limerick
Issue date:	12/08/2011
From:	Bill Dean Region 1 Administrator
To:	Pacilio M Exelon Generation Co, Exelon Nuclear
McLaughlin M
References
EA-11-221, IR-11-009 EA-11-221
Download: ML113410132 (8)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION

REGION I

475 ALLENDALE ROAD KlNG OF PRUSSlA. PA 19406-1415

SUBJECT:

FINAL SIcNIFICANCE DETERMINATION FOR A WHITE FINDING WITH ASSESSMENT FOLLOW-UP AND NOTTCE OF VTOLATION INRC INSPECTION REPORT NO. 05000353/201 10091 - LlMERTCK GENERATING STATION, UNIT 2

Dear Mr. Pacilio:

This letter provides you the final significance determination for the preliminary White finding discussed in the U.S. Nuclear Regulatory Commission (NRC) letter dated November 4,2011, as well as the NRC assessment of the current performance of the Exelon Generation Company, LLC (Exelon) Limerick Generating Station (Limerick) Unit 2. This updated assessment of Limerick Unit 2 supplements, but does not supersede, the NRC annual assessment letter issued on March 4,2A11 (M1110620350)1.

As described in the November 4,2011 letter, the self-revealing finding was recognized by Limerick staff on May 23, 2011, and reviewed during an NRC inspection completed on September 30, 2011. The finding involved the failure by Exelon to ensure sufficient technical guidance was contained in operating procedures to: (1) ensure that a feedwater (FW) motor operated valve (MOV) could close against expected system differential pressures; and (2)

prevent operators from attempting to close FW MOVs out of sequence resulting in differential pressures for which they are not designed. As a result, two FW valves (one of which was a primary containment isolation valve (PCIV)) failed to fully shut when Exelon operators at Limerick attempted to close them in order to secure a FW system flush. Consequently, from April 23 to May 23,2011, the PCIV was inoperable for greater than its Technical Specification allowed outage time. Additionally, because the Limerick Unit 2 reactor core isolation cooling (RCIC) system discharges to the reactor via the B FW header, with the affected FW valves cracked open, a flow path existed for RCIC to flow to the main condenser instead of the reactor.

As a result, in this configuration, RCIC would not have been able to supply design flow to the reactor. Consequently, for this same time period, the Limerick Unit 2 RCIC system was also

Designation in parentheses refers to an Agency-wide Documents Access and Management System (ADAMS) accession number. Documents referenced in this letter are publicly-available using the accession number in ADAMS.

M. Pacilio 2 inoperable for greater than its Technical Specification allowed outage time. The finding was presented at an exit meeting held at the conclusion of the inspection on October 7,2011, and is described in detail in the subject inspection report (NRC Inspection Report 05000352/2U1044 and 050003531201 1 004; ML113088146).

The November 4, 2011,letter also included an offer for Exelon to attend a regulatory conference or reply in writing to provide its position on the facts and assumptions the NRC used to arrive at the finding and its safety significance. In a letter dated November 14,2011, William Maguire, Limerick Site Vice President, indicated that Exelon did not contest the characterization of the risk significance of this finding and that Exelon declined its opportunity to discuss this issue in a regulatory conference or to provide a written response. After considering the information developed during the inspection, the NRC has concluded that the inspection finding is of low to moderate safety significance, and is therefore appropriately characterized as White.

As a result of the NRC review of the performance at Limerick Unit 2, including this White finding in the Mitigating Systems Cornerstone, the NRC has assessed Limerick Unit 2 to be in the Regulatory Response column of the NRC Action Matrix, retroactive to the beginning of the third cafendar quarter of 2011. Therefore, we plan to conduct a supplemental inspection using Inspection Procedure 95001, "lnspection for One or Two White lnputs in a Strategic Performance Area," when Exelon staff notify us of their readiness for this inspection. This inspection is conducted to provide assurance that the root cause and contributing causes of risk significant performance issues are understood, the extent of condition is identified, and the corrective actions are sufficient to prevent recurrence.

The NRC has also determined that the finding involved violations of NRC regulations, as cited in the enclosed Notice of Violation (Notice), and described in detail in the subject inspection report.

In accordance with the NRC Enforcement Policy, the Notice is considered an escalated enforcement action because it is associated with a White finding.

The NRC has concluded that information regarding: (1) the reason for the violations; (2) the actions planned or already taken to correct the violations and prevent recurrence; and, (3) the date when full compliance was achieved, is already adequately addressed on the docket in NRC lnspection Report 0500035212011004 and 05000353/2011004 and this letter. As described in the subject inspection report, upon identification of the issue on May 23,2011, Exelon staff fully closed the FW valves, which restored operability to the RCIC system and the PCIV. Additionally, Exelon has planned long-term corrective actions to address this issue, including revising the applicable procedure, performing maintenance and testing on the valves, and revising the scope for preventative maintenance of the valves. Therefore, Exelon is not required to respond to this letter unless the description therein does not accurately reflect Exelon's corrective actions or its position.

M. Pacilio 3 In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter, its enclosure, and your response, if you choose to provide one, will be made available electronically for public inspection in the NRC Public Document Room located at NRC Headquarters in Rockville, MD, and from the NRC's Agency-wide Documents Access and Management System (ADAMS), accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html. To the extent possible, your response, if you choose to provide one, should not include any personal privacy, proprietary, or safeguards information so that it can be made available to the Public without redaction.

Regional Administrator Docket No, 50-353 License No. NPF-85 Enclosure:

Notice of Violation cc w/encl: Distribution via ListServ