ML20215B234

Addresses Concerns Re Inservice Duration of Installed Valve Primer & Trigger Assemblies,Resulting from Rescheduling Oct 1986 Refueling Outage to Jan 1987.Continued Operation of Components Until Jan 1987 Not Adverse to Public Safety

ML20215B234
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	09/25/1986
From:	Frisch R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	Office of Nuclear Reactor Regulation
References
NUDOCS 8610060433
Download: ML20215B234 (2)

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1. .C Consurners

@rewauns AMDNEAF5 PNSENE55 Power General offices: 1945 West Parnell Road, Jackson, MI 49201 . (517) 788-0550 September 25, 1986 Director, Nuclear Reactor Regulation US Nuclear Regulatory Commission Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -

ENGINEERING EVALUATION OF SQUIB VALVE PRIMER AND TRIGGER ASSEMBLY INSERVICE DURATION Big Rock Point Technical Specification 5.2.3 states the following regarding test-firing and operation of the squib valves in the Liquid Poison System:

"One squib primer and trigger assembly from the equalizing lite shall be removed and test-fired at least every 18 months. These shall be tested on an alternate basis ensuring valve replacement every 36 months. One 8luib primer and trigger assembly from the remaining five units shall be removed and test-fired at least every 18 months. These shall be tested on an alternate basis. In no case shall a squib primer and trigger assembly remain in service longer than five years."

Current practices meet the above testing requirements and are scheduled to ensure all primer and trigger assemblies are test-fired and replaced with new units every five years (approximately four operating cycles). A recent decision to delay the start of the next refueling outage from October 1986 to January 1987, has raised concerns regarding the life cycle of the enrrently installed primer and trigger assemblies.

The seven squib valve primer and trigger ossemblies in use at Big Rock Point were installed on the following dates:

Equalizing Line Valves - 04/08/85, 09/20/85 Nitrogen Supply Valves - 03/04/82, 07/06/84 Poison Line Valves - 09/20/85, 04/08/85, 06/14/83 This data shows that in accordance with Technical Specification 5.2.3 the next test-firing on en equalizing line valve and one of the remaining valves is due on March 20, 1987. Additionally, to ensure that a primer and trig,ger assembly does not remain in service longer than five years, one of the Nitrogen Supply Valves needs replacement by March 4, 1987. However, the vendor recommends that the primer and trigger assemblies be repisced five (5) years after delivery (manufacturing date stamped on the unit). ,

8610060433 860'125

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Director, Nuclear Reactor Regulation 2 Big Rock Point Plant Engineering Evaluation of SQUIB Valve Primer and Trigger Assembly Inservice Duration September 25, 1986 All of the currently installed primer and trigger assemblies were delivered in November 1981 with manufacturing date stamps of November 30, 1981. To address leaving the primer and trigger assemblics in service longer than the five year vendor recommendation, the vendor was contacted. They responded in writing that the useful life of the primer and trigger assemblies could be extended safely three to four months past the five year manufacturing expiration date and that the five year recommendation is admittedly on the conservative side.

The response also stated that they have never detected any deterioration on primer and trigger assemblies following removal fron service and test-firing after five years of use/ storage.

Also, vendor documentation (storage life versus temperature curve) shows that expected lifetime can exceed ten years when ambient temperatures are kept at 120*F or below. Degradation is primarily temperature dependent. At Big Rock Point, storeroom temperatures run between 65* - 90*F. To ensure that the temperatutes of the primer and trigger assemblies remain below 120*F, the installed assemblies are, continuously monitored by thermocouples and a temper-ature recorder which alarms in the control room should any valve reach 120*F.

A review of installation location temperatures shows a maximum of approximate-ly 110*F. Both the installed location and storeroom temperatures are below 120*F.

Big Rock Point's current plans are to leave the primer and trigger assemblies "

in service until the January 1987 Refueling Outage, at which time all seven units will be replaced. Subsequent testing and replacement will be resumed in accordance with Technical Specification 5.2.3 following the outage. The Plant Review Committee has reviewed this engineering evaluation and found it accept-able to operate until the January 1987 Refueling Outage with the current assemblies in service withaut causing undue risk to public health and safety.

Ralph R Frisch Senior Licensing Analyst CC Administrator, Region III, USNRC NRC Resident Inspector - Big Rock Point Plant OC0986-0158-NLO2