ULNRC-05932, Special Report 2012-02 - Pam Report: Inoperability of a Post Accident Monitoring (PAM) Instrument for Greater than 30 Days

Special Report 2012-02 - Pam Report: Inoperability of a Post Accident Monitoring (PAM) Instrument for Greater than 30 Days

ML123200536
Person / Time
Site:	Callaway
Issue date:	11/14/2012
From:	Neterer D W Ameren Missouri, Union Electric Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
ULNRC-05932 Special Report 12-02
Download: ML123200536 (4)

Text

WAmeren MISSOURI Callaway Plant **************************************************************************************************************************************************************************************************************************************************

November 14,2012 ULNRC-05932 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Ladies and Gentlemen:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO. FACILITY OPERATING LICENSE NPF-30 SPECIAL REPORT 2012-02-PAM REPORT: INOPERABILITY OF A POST ACCIDENT MONITORING (PAM) INSTRUMENT FOR GREATERTHAN30DAYS Attached is a special report (PAM Report) addressing the inoperability of a containment normal sump water level instrument at Callaway.

No new commitments are identified in this correspondence.

None of the material in this report is considered proprietary by Union Electric.

If you have any questions or require additional information, please contact Mr. Thomas Elwood, Supervising Engineer, Regulatory Affairs and Licensing at 314-225-1905.

EMP/nls Enclosure

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..... ............................................. . Sincerely, David W. Neterer Plant Director PO Box 620 Fulton, MO 65251 AmerenMissouri.com ULNRC-05932 November 14,2012 Page2 cc: Mr. Elmo E. Collins Regional Administrator U.S. Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Fred Lyon Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-8B 1 Washington, DC 20555-2738 ULNRC-05932 November 14,2012 Page 3 Index and send hardcopy to QA File A160.0761 Hardcopy:

Certrec Corporation 4150 International Plaza Suite 820 Fort Worth, TX 76109 (Certrec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via Responses and Reports ULNRC Distribution:

A. C. Heflin F.M.Diya C. 0. Reasoner III L. H. Graessle S. A. Maglio T. B. Elwood R. Holmes-Bobo NSRB Secretary Mr. Bill Muilenburg (WCNOC) Mr. Tim Hope (Luminant Power) Mr. Ron Barnes (APS) Mr. Tom Baldwin (PG&E) Mr. Mike Murray (STPNOC) Ms. Linda Conklin (SCE) Mr. John O'Neill (Pillsbury Winthrop Shaw Pittman LLP)

Enclosure to ULNRC-05932 Requirement Special Report 2012-02 PAM Report Callaway Plant Unit 1 Technical Specification (TS) 3.3.3, "Post Accident Monitoring (PAM) Instrumentation", contains requirements for Containment Normal Sump Water Level Instrumentation.

TS 3.3.3 Limiting Condition for Operation (LCO) requires two channels of Containment Normal Sump Water Level Instrumentation to be Operable while in MODES 1, 2, 3. With one ofthe required instruments inoperable for more than 30 days, Required Action B.1 applies. It states, "Initiate action in accordance with Specification 5.6.8." TS 5.6.8, "PAM Report", states, "When a report is required by Condition B or F ofLCO 3.3.3, 'Post Accident Monitoring (PAM) Instrumentation', a report shall be submitted within the following 14 days. The report shall outline the preplanned alternate method of monitoring, the cause of the inoperability, and the plans and schedule for restoring the instrumentation channels of the Function to OPERABLE status." Summary of the PAM Instrument In operability On October 13, 2012, Operations declared one channel of the Containment Normal Sump Water Level Instrumentation inoperable.

During a review of Reactor Operator logs, it was noticed that the containment normal sump level indicator, LFLIOO 10 CTMT NORM SMP WEST LEV IND, had been constant since 10/07/2012, while indications on other sump level indicators appeared to have properly varied with actual sump level changes. After power to the sump level indicator was cycled, indications returned to normal trending on 10/24/2012.

Further review of logs revealed erratic indications during high temperature periods but indications returned to normal following minor manipulations of the instrument loop. Pre planned Alternate Method of Monitoring Associated sump level indicator, LFLI0094 CTMT NORM SMP WEST LEV IND, provides an alternate means for monitoring the containment normal sump water level (in the same area of the sump monitored by the LFLIOO 10 indicator).

This instrument provides adequate indication of a potential flooding condition in containment during a design basis accident.

Cause of the Inoperability The cause of the erratic performance of the sump level indicator has been determined to be an electrical problem. The most likely sources of an electrical issue were determined to be a stuck reed switch in the float assembly, a faulty connection in the float assembly, or a faulty splice in the containment penetration.

Further troubleshooting is required and is being pursued. Plans and Schedule for Restoring the Instrumentation Channel to OPERABLE status Based on this preliminary evidence, a decision was made to replace the level transmitter and to rework inner/outer penetration splices. This is currently scheduled to occur between November 13th and November 16th 2012. Additionally, we are planning to replace the lower float level element (located in containment) during the next refueling outage. This is currently scheduled for April2013.

Completion of the transmitter and penetration work will be completed prior to any operability determination.