ULNRC-05089, Special Report on the Inoperability of Unit Vent High Range Radiation Monitor

Special Report on the Inoperability of Unit Vent High Range Radiation Monitor

ML043220471
Person / Time
Site:	Callaway
Issue date:	11/10/2004
From:	Keith Young AmerenUE
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ULNRC-05089
Download: ML043220471 (4)

Text

• - 'N AmerenUE PO Box 620 CallawayPlant Fulton, MO 65251 November 10, 2004 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 UTLNRC-05089 WAmeren Ladies and Gentlemen:

UE DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

FACILITY OPERATING LICENSE NPF-30 Special Report on the Inoperability of Unit BTent High Range Radiation Monitor The enclosed Special Report is submitted in accordance with Final Safety Analysis Report (FSAR) section 16.3.3.4, Accident Monitoring Instrumentation Limiting Condition for Operation. On October 22, 2004, the Unit Vent Mid and High Range monitors were declared Inoperable and this report documents the cause of the inoperability, the actions taken to restore the monitors to an Operable status, and the preplanned alternate monitoring methods established during the time of Inoperability.

This letter does not contain new commitments.

Sincerely, eith D. Young Manager, Regulatory Affairs Enclosure 6

a subsidiary of Ameren Corporation

UTLNRC-05089 November 10, 2004 Page 2 cc: U.S. Nuclear Regulatory Commission (Original and I copy)

Attn: Docunment Control Desk Mail Stop P1-137 Washington, DC 20555-0001 Mr. Bruce S. Mallett Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)

Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 7EI Washington, DC 20555-2738 Missouri Public Service Commission Governor Office Building 200 Madison Street PO Box 360 Jefferson City, MO 65102-0360

ULNRC-05089 November 10, 2004 Page 3 bcc: G. L. Randolph (w/o)

C. D. Naslujid (w/o)

K. D. Young (w/o)

G. A. Hughes (w/a)

D. E. Shafer (w/a) (470) (2 copies)

S. L. Gallagher (w/o) (100)

S. L. Klang (w/a) (NSRB)

M. A. Reidmeyer (w/a)

J. E. Ready (w/o)

E210.0001 A160.0761 Chrono file The following are sent without attachments:

Ms. Diane M. Hooper Mr. Dennis Buschbaum Supervisor, Licensing TXU Power WCNOC Comanche Peak SES P.O. Box 411 P.O. Box 1002 Burlington, KS 66839 Glen Rose, TX 76043 Mr. Scott Bauer Mr. Stan Ketelsen Regulatory Affairs Manager, Regulatory Services Palo Verde NGS Pacific Gas & Electric P.O. Box 52034, Mail Stop 104/5/536 Mail Station 7636 P.O. Box 56 Phoenix, AZ 85072-2034 Avila Beach, CA 93424 Mr. Scott Head Certrec Corporation Supervisor, Licensing 4200 South Hulen, Suite 630 South Texas Project NOC Fort Worth, TX 76109 Mail Code N5014 P.O. Box 289 Wadsworth, TX 77483 Mr. John ONeill Shaw, Pittman 2300 N. Street N.W.

Washington, DC 20037

ULNRC-05089 November 10, 2004 Page 1 of I Special Report: Inoperability of GTRE002IB During quarterly Surveillance testing of the Unit Vent Radiation Monitor on October 22, 2004, the Mid/High Range Channel flow control circuit failed to achieve the required sample flow necessary for isokinetic sampling. Troubleshooting ultimately determined that the failure was due to improper reassembly of a filter canister located between the Mid/High Vacuum Pump discharge and the Mid/High Range Detector Chambers. The design of this filter relies on a tapered flange between both the canister body and canister lid which compresses a sealing o-ring when coupled together using a constricting steel band. Following discovery of the failure mechanism investigation revealed that the faulty reassembly occurred on October 5, 2004 when the filter was last replaced. Performance of the quarterly Surveillance was not coordinated with the filter replacement activity delaying the identification of faulty reassembly. The canister was properly reassembled and a tight seal was verified by achieving correct flow characteristics for the Mid/High Range flow control circuit. On October 28, 2004, the Mid/High Range Unit Vent Radiation Monitor was declared Operable and returned to service.

During the performance of the quarterly Surveillance on October 22, 2004, the preplanned alternate method of monitoring was instituted in accordance with plant procedures. This constituted monitoring Unit Vent releases in accordance with Emergency Plan Implementing Procedures in the event an emergency were to occur and would rely upon data supplied by field monitoring teams. This alternate method remained in effect until the problem was corrected on October 28, 2004.