DCL-86-106, Special Rept SR 86-02:on 860331,main Steam Line Radiation Monitor RM-71 Inoperable for More than 7 Days.Caused by Failed Power Supply & Log Rate Circuit Boards.Alternate Radiation Monitoring Methods Established

Special Rept SR 86-02:on 860331,main Steam Line Radiation Monitor RM-71 Inoperable for More than 7 Days.Caused by Failed Power Supply & Log Rate Circuit Boards.Alternate Radiation Monitoring Methods Established

ML20203M923
Person / Time
Site:	Diablo Canyon
Issue date:	04/21/1986
From:	Shiffer J PACIFIC GAS & ELECTRIC CO.
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
DCL-86-106, SR-86-02, SR-86-2, NUDOCS 8605020161
Download: ML20203M923 (1)

Text

_ _ _ _ _ _ _ _ __ -

PACIFIC GAS AND ELECTR,IC C O M PANY bbEM h 77 BEALE STREET . SAN FRANCISCO, C Alt FORNI A 94106 . (415)781 4211

• TWX 910-372 6587 awn nn PGandE Letter No.: DCL-86-106 g, 2 M * ,Js Mr. John B. Martin, Regional Administrator R

E U. S. Nuclear Regulatory Comission, Region Y ' M' G 3

1450 Maria Lane, Suite 210 N A Walnut Creek, CA 94596-5368 l Re: Docket No. 50-275, OL-DPR-80 Diablo Canyon Unit 1 Special Report on Inoperability of Main Steam Line Radiation Monitor, SR 86-02

Dear Mr. Martin:

In accordance with the requirements of the Diablo Canyon Technical Specifications 6.9.2 and 3.3.3.6 Action d., this Special Report is being submitted concerning the Unit 1 Main Steam Line Radiation Monitor (RM-71) being inoperable greater than 7 days.

On March 31, 1986, during the performance of Surveillance Test Procedure STP I-18R1, " Functional Test of Main Steam Line Radiation Monitors," RM-71 was found to be inoperable. In accordance with STP G-16, " Alternate Methods of Monitoring for High Range Accident Radiation Monitors," and Technical Specification 3.3.3.6 Action d., within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (on April 3,1986), alternate mathods of monitoring for high-range postaccident radiation were established at Main Steam Line 1-1.

Extensive troubleshooting revealed that the inoperability of RM-71 was caused by a failed power supply circuit board and log rate circuit board. The monitor was repaired and returned to operable status on April 11, 1986.

Compensatory measures were 'aken in accordance with the Technical Specifications to provide a temporary accident radiation monitor. Therefore, no safety consequences or implications have resulted from this event.

Kindly acknowledge receipt of this material on the enclosed copy of this letter and return it in the enclosed addressed envelope.

Sincerely, J. .. hiffer cc: L. J. Chandler R. T. Dodds B. Norton H. E. Schierling S. A. Yarga h50 S

860421 l 05000275 l CPUC PDR I Diablo Distribution Document Control Desk 0830S/0043K/JHA/882

{ l

_ _ _ _ _