ML20045G791

LER 93-005-00:on 930608,indicated That Response Time Test for RCIC Low Steam Pressure Isolation Instrumentation Invalid.Caused by Inappropriate Test Method.Procedures Governing Method of Testing Will Be revised.W/930708 Ltr

ML20045G791
Person / Time
Site:	Grand Gulf
Issue date:	07/08/1993
From:	Hutchinson C, Ruffin R ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GNRO-93-00086, GNRO-93-86, LER-93-005, LER-93-5, NUDOCS 9307150195
Download: ML20045G791 (5)

Text

' Entergy Operatione,inc.

" ENTERGY -so f9t GJ '.un.MS 39150 TM 631437 M00 C. R. Hutchinson July 8, 1993 y'[ ' '

aurano e w U.S. Nuclear Regulatory Commission Mail Station Pl-137 Washington, D.C. 20555 Attention: Document Control Desk

SUBJECT:

Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 Reactor Core Isolation Cooling Steam Pressure Instrumentation not Properly Surveilled LER 93-005-00 GNRO-93/00086 Gentlemen:

Attached is Licensee Event Report (LER)93-005 which is a final report.

Yours truly, ,

y _ Wk-i sl Y T[i,A '

CRH/RR/

attachment cc: Mr. R. H. Bernhard(w/a)

Mr. H. W. Keiser(w/a)

Mr. R. B. McGehee (w/a)

Mr. N. S. Reynolds (w/a)

Mr. H. L. Thomas (w/o)

Mr. Stewart D. Ebneter (w/a)

Regional Administrator U.S. Nuclear Regulatory Commission Region II {

101 Marietta St., N.W., Suite 2900 '

Atlanta, Georgia 30323 Mr. P. W. O'Connor Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 13H3 Washington, D.C. 20555 9307150195 930708 PDR ADOCK 05000416 eJR s j

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F ACtEITY NAME (1) DOCr,ET NUMBER p) PAGE .(3)

Grand Gulf Nuclear Station 05000-416 01 of 04

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Reactor Core isolation Cooling Steam Pressure instrumentation Not Properly Surveilled EVENT DATE (5) LER NUMBER (6) REPORT NUMBER (7) OTHER FACILITIES INVOLVE D (8)

MONTH DAY YE AR VLAR SEQUENT 6AL RE WSiON MONTH DAY YEAR f ACluiY NAME DOGr.El NUMBER NW (R NMR N/A 05000 ,

F ALIUT Y NAME DOCKET Nut.tbER 06 08 93 93 005 00 07 08 93 N/A 05000  ;

OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR $ (Check one or more (11)

MODE (9) 1 20 402(b) 20 405(c) 50.73(a)(2)(iv) 73 71(b)

POWER 20 405(a)(1)(a) 50.36(c)(1) 50 73(a)(2)(v) 73 71(c) l LEVEL (10) 100 20 405(a)(1)(ii) 50.36(c)(2) 50 73(a)(2)(vn) OTHER 1 20.405(a)(1)(ui) X 50.73(a)(2)(1) 50.73(a)(2)(vni)( A) l,5gga,*g*gio* *ad "'

20 405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(vni)(B) 20 405(a)(1)(v) 50.73(a)(2)(ni) 50.73(a)(2)(x)

LICENSEE CONTACT FoR THis LER (12)

NAME TELEPHONE NUMBEN rnciase Area Code)

Riley Ruffin / Licensing Specialist 601-437-2167 l COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THis REPORT (13) {

cAuSE S YS TEM COMPord NT MANUF ACTUNEN f TAB E CAUSE S M.R M LCWONU.T MANUF AC TUREN Rt i RE EXPECTED M "'" D*' " EAR SUPPLEMENTAL REPORT EXPECTED (14)

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DATE (15)

ABSTRACT rum,e to mo w.m i. .opumm my ,s w+.*.c.a to.-meonnuita iI i

On June 8,1993 during a review of Westinghouse response time test results, it was indicated that the response time test for the Reactor Core Isolation Cooling (RCIC) low steam pressure isolation instrumentation was invalid. The Westinghouse process noise (" white noise") method had been used for the response time testing during the last three test. RCIC was declared inoperable and the pressure instrumentation was tested using the hydrualic ramp method. The test was sucessfully completed and RCIC was restored to operable status. The white noise method will not to be used for response time testing for the subject instrumentation. No safety functions or components were compromised as a result of this condition. Therefore the condition did not adversely impact the health and safety of the public.  !

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F ALILilf NAML (1) DOCAL1 NUMulH (i') LLH NUYbtR (0) PAusth Grand Gulf Nuclear Station 05000-418 93-005-00 2 OF 04 m on,-. ,w. ,, ,.n.u.. .sa-, n., mc w,, mAnm A. Reportable Occurrence On June 8,1993, it was discovered that the method used to satisfy Technical Specification (TS) required response time testing for Reactor Core isolation Cooling (RCIC) (BN] isolation instrumentation did not adequately test the required parameter. This is considered a condition prohibited by TS. This event is being reported pursuant to 10 CFR 50.73(a)(2)(i)(B).

B. Initial Conditions The plant was in Operational Condition 1 with reactor water at approximately 531 degrees F.

The plant was operating at approximately 100 percent thermal power at the time of discovery.

C. Description of Occurrence TS Surveillance Requirement 4.3.2.3 requires that the ISOLATION SYSTEM RESPONSE TIME be demonstrated within specified limits once per 18 months.

On June 8,1993 during a review of results from isolation instrumentation response time testing, Westinghouse personnel indicated in the test report that results associated with the RCIC Steam Supply Pressure Low instrumentation were not valid.

These pressure instruments monitor steam supply piping for RCIC to detect gross leaks that may occur upstream of high flow isolation instruments. Testing is intended to verify instrument response times are within required limits, in order to ensure proper operation of instrumentation necessary for a RCIC steam line isolation. However, tests which were performed to satisfy the TS requirement 4.3.2.3 since April 1989 were invalid.

Subsequent to the April 1989 test, a new method of response time testing was introduced by Westinghouse. This new method of testing could be performed during full-power operations.

Prior to the new test method a hydrualic ramp method was used. The ramp method required removal of systems / components from service prior to testing. The White Noise method of  :

testing was used to reduce the outage workload.

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Grand Gulf Nuclear Station 05000-416 93-005-00 3 OF 04 7Lu w am wa. a ,, van m .asana< ces or unc r xm sssa) o o The test method wm reviewed prior to implementation at the plant site. However, no noticeable differ /ere identified when compared to the hydraulic ramp method of testing.

D. Apparent Cause Following the discovery, an investigation was performed and the root caused determined..

During normal condition, the RCIC Low Steam Supply Pressure Isolation Instrumentation is saturated (off-scale High). The process noise analysis test method was inappropriate for instrumentation that is in a saturated condition.

Westinghouse was unaware of the implication of using " white noise" analysis on saturated transmitters. The test limitations were unknown to plant personnel, and were not identified by Westinghouse personnel prior to testing in May 1993.

E. Corrective Action l

Upon discovery, the RCIC system was declared inoperable. Low pressure instrumentation for i the RCIC isolation was successfully tested using the hydraulic ramp method and response j times were verified to be within specified limits. The white noise method will not be used for l response time testing for the subject instrumentation.  !

l A review was performed to ensure all other tests being performed using the process noise I analysis method were satisfying appropriate requirements. J l

Plant procedures which govern this method of testing will be revised to include information for  ;

instruments which are off scale high during testing.

F. Safety Assessment 4 The RCIC Steam Supply instruments monitor steam supply piping for RCIC to detect gross leaks that may occur upstream of high flow isolation instruments. The isolation function is used to reduce the loss of reactor vessel inventory in the event of a RCIC steam line break. 1 4

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Grand Gulf Nuclear Station 05000-416 93-005-00 4 OF 04 u n T e na. ap.:. ,, ,.quw.a u . .ae non.1 coo,,, cx Nuu re,m .ror.>> < s ii Following discovery of the condition, the affected instrumentation was tested. The test verified instrument response times were within their specified limits. No safety functions or components were compromised as a result of the condition. Therefore the condition did not adversely impact the health and safety of the public.

G. Additional Information Energy Industry identification System (Ells) codes are identified in the text within brackets [).

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