ML20040C947

LER 81-034/03L-0:on 811211,loop 2 Steamline Pressure Channel Indicated Higher than Other Channels.Caused by Frozen Sensing Lines in Pressure Transmitter & Failure to Return Freeze Protection Circuit to Svc After Maint

ML20040C947
Person / Time
Site:	Robinson
Issue date:	01/08/1982
From:	Cox H CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20040C834	List: ML20040C833 ML20040C947
References
LER-81-034-03L, LER-81-34-3L, NUDOCS 8201290400
Download: ML20040C947 (2)

Text

, CRC F6pM 366 U. S. NUCLEAQ REGULATGXY COMMISSION (7 77)

'h LICENSEE EVENT REPORT CONTROL. CLOCK: l 1

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(PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) 7 0 t 8 9 i s l C i n l 8 lR l 2 lg 01 01 -l 0 l 0l 0l 0l 0 l -l 0 l 0 l@

LICENSEE CODE 14 15 UCENSE NUMBER 25 4 l 1 l 1 l 1 l 1 l@lS7 CAT 26 LICENSE TYPE JO l' 68l@

CON'T o i g"7 Ql0 l5 l0 l0 l0 l2 l6 l1 @l 68Il 21 69 I l EVENT Il 81DATE1 l@[0_{ l l 0REPORT 74 75 l 8 DATE l 8 l 280l@

7 8 60 68 DOCKET NUMBER EVENT DESCRi? TION AND PROBABLE CONSEQUENCES h o 2 lOn December 11, 1981, a t approxima tely 0700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br /> with the unit at 59% power. Loop 2 l o 3 lSteamline Pressure Channel II (PI-484) was observed to be indicating high as compared l o 4 lto the other channels and was declared inoperable. Investiga tion revealed tha t the _j i

o s lhigh reading was due to frozen transmitter sensing lines. This event resulted in less l o s lthan the minimum degree of redundancy as required by Technical Specification table 1 o 7 l3.5-3 and is reportable pursuant to 6.9.2.b.2. The remaining steam line pressure l

, o a l channels were operable so there was no threat to the public health and safety. l 7 89 80 DE CO E S E COMPONENT CODE SU8 Code SU E M 11 l8 l@ LAJ@ L cJ @ I I I N l S l T l R lU lh [_Tjh20 [fj h I

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, o lThe cause of failure was due to an out of service Freeze Protection Circuit. 'Ih e l 3 i l Freeze Protection Circuit for PT-484 was put in service, the sensing lines thawed, and I

, , , lPT-484 was declared operable at 0841 hours0.00973 days <br />0.234 hours <br />0.00139 weeks <br />3.200005e-4 months <br /> on December 11, 1981. To prevent l

> g l recurrence, beginning February 1,1982, all maintenance work on freeze protection l circuits will be performed in accordance with the Local Clearance and Test Request 1 4 lorocedure. ]

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h SUPPLEMENTAL INFORMATION FOR LICENSEE EVENT REPORT 81-034

1. Cause Description and Analysis On December 11, 1981, at approximately 0700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br /> with the unit at 59%

power, Loop 2 Steamline Pressure Channel II (PI-484) was observed to be indicating high as compared to the other channels and was declared inoperable. Investigation revealed that the pressure transmitter sensing lines had frozen which caused the abnormal indication.

Additionally, it was determined that the Freeze Protection Circuit for this transmitter and sensing lines had been repaired on Decembe r 10, 1981, but through oversite had not been returned to se rvice by the maintenance personnel.

This event resulted in less than the minimum degree of redundancy for High Steam Line Differential Pressure Protection as required by Technical Specification table 3.5-3 and is reportable pursuant to 6.9.2.b.2. The bistables associated with PT-484 were placed in the trip position which restored the required degree of redundancy so there was no threat to the public health and sa fet y.

2. Corrective Action The Freeze Protection Circuit was turned on by maintenance personnel; the sensing lines thawed in approximately 15 minutes. PT-484 wa s declared operable at 0841 hours0.00973 days <br />0.234 hours <br />0.00139 weeks <br />3.200005e-4 months <br /> on December 11, 1981.

3.

Corrective Action to Prevent Recurrence All personnel who perform maintenance on Freeze Protection Circuits have been cautioned as to the importance of returning these circuits to service promp tly, particula rly during periods of cold wea ther.

These individuals will review this LER as re-inforcement of this cau t ioning. In addition, beginning February 1,1982, all maintenance work on Freeze Protection Circuits will be performed in accordance with the Local Clearance and Test Request (LCTR) procedure. This is considered suf ficient corrective action to prevent recurrence of this type of even*