05000280/LER-1985-019, :on 850927,individual Rod Position Indicator for Two Rods Inoperable.Spurious Incorrect Rod Position Indication Is Generic Westinghouse PWR Concern.Portion of Sys Outside Containment Tested & No Problems Found

:on 850927,individual Rod Position Indicator for Two Rods Inoperable.Spurious Incorrect Rod Position Indication Is Generic Westinghouse PWR Concern.Portion of Sys Outside Containment Tested & No Problems Found

ML20138M612
Person / Time
Site:	Surry
Issue date:	10/25/1985
From:	Saunders R VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML20138M602	List: 05000280/LER-1985-019, :on 850927,individual Rod Position Indicator for Two Rods Inoperable.Spurious Incorrect Rod Position Indication Is Generic Westinghouse PWR Concern.Portion of Sys Outside Containment Tested & No Problems Found 05000280/LER-1985-020, :on 850927,following Controlled Shutdown Due to Hurricane Gloria,Iodine Spike Discovered.Caused by Known Fuel Element Defects in Reactor Core.Level of Dose Equivalent I-131 Monitored Per Tech Spec Table 4.1-2B ML20138M600
References
LER-85-019, LER-85-19, NUDOCS 8511040150
Download: ML20138M612 (3)

LER-1985-019, on 850927,individual Rod Position Indicator for Two Rods Inoperable.Spurious Incorrect Rod Position Indication Is Generic Westinghouse PWR Concern.Portion of Sys Outside Containment Tested & No Problems Found

Event date:
Report date:
2801985019R00 - NRC Website

text

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^2C Fo,e 366 U.S. NUCLEGR QEGULQTOQV COMMISSION M3' OCPROVED OM8 NO. 3150-4104 LICENSEE EVENT REPORT (LER)

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PQCJLITV NAME (1)

DOCKET NUMBER (21 MO 08 Surry Power Station, Unit I o l5 ;o ;o 10l 21 810 1loF!013 YtTLE (4)

Degraded IRPI EVENT DATE (5)

LER NUM8ER 86)

REPORT DAT E (7)

OTHER F ACILITIES INVOLVED (Si S'y M L*'

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NAMg TELEPHONE NUM8ER ARE A CODE R. F. Saunders, Station Manager 81 014 3I5171-13111814 COMPLETE ONE LINE FOR EACM COMPONENT F AILURE DESCRIBED IN THIS REPORT (13)

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ASSTDACT (Lomit to 1400 aveces. I e, scorewetery t! teen, eng e,oece typewritsen Ioneel t1SI ABSTRACT On September 27 and October 13, 1985 with the unit at power, IRPI for two rods in one group were inoperable. For both events, at least one IRPI was returned to service within two hours. Operations with IRPI for two rods in one group inoperable is prohibited by station Technical Specifications.

Control rod position indication is provided by the individual rod position indicator (IRPI), which has no safety function. During this event, core data was being monitored to assure core power distribution limits were not exceeded. Also, an inoperable IRPl will not affect the operation of the centro' ad assembly and each rod was capable of being dropped if required. Therefore, the health and safety of the public was not

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POW 28-06-01 NAC F.ra. 3e6A U S NUCLEAR REGULATOMY COMMISEl"JN LICENSEE EVENT REPORT (LER) TEXT CONTINUATION AnnaovEo ove =o siso-oio.

EPiRES 8/31 SS F ACILITY NAME (16 DOCKET NUMS&R (2l (gn Nyggga 133 PAGE(31 "5;P.

7,'Jo*.O aaa Surry Power Station, Unit I ol5tololol 2l 8 l 0. 815 O!I l 9 O l0 0b 0F 0l3 rnxr a

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ec v,.sawonm DEGRADEDIRPI 1.

Description of the Event on September 27, 1985 at 0012 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> with the unit at 30% power and ramping off line due to an approaching hurricane, the individual rod position indication (IRPI) for Rod D-12 of C Bank (Group 1) indicated more than 12 steps below the bank demand position. The IRPI for Rod D-12 was declared inoperable per T.

S..

Prior to this event, Rod D-4 of C Bank (Group 1) had been indicating more than 12 steps from the Bank demand position and had been declared inoperable.

In addition, on October 13,1985 at 0715 hours0.00828 days <br />0.199 hours <br />0.00118 weeks <br />2.720575e-4 months <br /> with the unit ramping up from 78%, IRPI for Rod D-12 indicated more than 12 steps from the Bank demand position and was declared inoperable.

IRPI for Rod D-4 had been previously declared operable.

At least one IRPI was returned to service within two hours for both events.

2.

Probable Consequences and Status of Redundant Equipment i

Control rod position indication is provided by the individual rod position indicator (IRPI), which has no safety function. During this event, core data was being monitored to assure core power distribution limits were not exceeded.

Also, an inoperable IRPI will not affect the operation of the control rod assembly and each rod was capable of being dropped if required. Therefore, the health and safety of the public was not affected.

3.

Cause

Spurious incorrect rod position indication is known to be a generic Westinghouse PWR concern. The instrumentation drift appears to be affected by l

prLaary coolant temperature and control bank movement.

l 4

Immediate Corrective Action

The portion of the system outside the containment was tested and no problems could be found.

The monitoring of core data was continued via T.S.3.12.E.2.2.

5.

Subsequent Corrective Action None.

6.

Action Taken to Prevent Recurrence No specific actions are required at this time.

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g,*-- sena LICENSEE EVENT REPORT (LER) TEXT CONTINUATION arraovgo ous =o aiso-oioa EmpiaE8 s.39 45 saceLITY Naast til DOCKET NURABla (2D ggn nynaggn ggi PaGE tm kN[g's (IugYa TEAR Surry Power Station, Unit 1 015 lo 10 l o l 218 I o als nli lo 01 0 01 3 0F 0l3 rixrn -

. - - ace as.,nn DEGRADED IRPI 7.

Generic implications IRPI drift is a known generic Westinghouse PWR concern.

NEC f onu 3een 10431