05000461/LER-1997-014, :on 880426,MSIV Closure Time Testing Was Not Adequate,Due to Procedural Inadequacy.Revised DPS 9061.09 to Account for Full Valve Travel & Verified MSIV Operability Before Plant Start Up

:on 880426,MSIV Closure Time Testing Was Not Adequate,Due to Procedural Inadequacy.Revised DPS 9061.09 to Account for Full Valve Travel & Verified MSIV Operability Before Plant Start Up

ML20141C479
Person / Time
Site:	Clinton
Issue date:	06/18/1997
From:	Allen J ILLINOIS POWER CO.
To:
Shared Package
ML20141C478	List: 05000461/LER-1997-014, :on 880426,MSIV Closure Time Testing Was Not Adequate,Due to Procedural Inadequacy.Revised DPS 9061.09 to Account for Full Valve Travel & Verified MSIV Operability Before Plant Start Up
References
LER-97-014, LER-97-14, NUDOCS 9706250245
Download: ML20141C479 (4)

LER-1997-014, on 880426,MSIV Closure Time Testing Was Not Adequate,Due to Procedural Inadequacy.Revised DPS 9061.09 to Account for Full Valve Travel & Verified MSIV Operability Before Plant Start Up

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(viii) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(1)
4611997014R00 - NRC Website

text

NRC FORM 366 U.S. NUCLEAR REGULATORY COMM1 SiON APPROVED BY Q K9 NO. 31504104 (4-95)

EZPIRES C4/30/96 ESTIMATED SUT.OEN PER RESPONSE TO COMPLY WITH THl3 MANDATO;1Y INFORMATION COLLECYlON REQUE ST: 50.0 F RS.

REPORTED LE SSONS LICENSEE EVENT REPORT (LER)

LEARNED ARE iNCORPORATEo wr0 THE LiCENsiNo PROCESS ANo FED BACx TO INDUSTRY. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THEi INFORMATION AND RECOROS MANAGEMENT BRANCH (T 6 F33L U.S.

NUCLEAR REGULATORY COMMISSION. WASHINGTON. DC 205554001. AND (See reverse for required number of TO THE PAPERWORK REDUCTION PROJECT (31504104h OFFICE OF digits / characters for each block)

M ANAGEMENT AND BUDGET, WASHINGTON. DC 20503.

FAcEJTV NAME (1) doc KET NUMBER (2)

PAGE (3)

Clinton Power Statl0n 05000461 1 OF 4 TITLE G3 Main Steam isolation Valves Closure Time Out of Technical Specifications Due to Procedural Inadequacy EVEPIT DATF m)

LER NUMBER f B REPORT D ATF (71 OTHER FACILfTIES INV 3LVED f BI MONTH DAY YEAR YEAR SEQUENTIAL RE VibiON MONTH DAY YEAR F AciuTY NAME DOCKET NUMBER NUMBE R NUMBER None 05000 04 26 88 97 014 00 06 18 97

'^CiuTY NAME DOCxET NuMsER None 05000 i

OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check one or more) (11)

M!DE (9) 4 20.2201(b) 20.2203(a)(2)(v)

X 50.73(a)(2)(i) 50.73(a)(2)(viii)

POWER 20.2203(a)(1) 20.2203(a)(3)(i) 50.73(a)(2)(ii) 50.73(a)(2)(x)

LEVEL (10) 000 20.2203(a)(2)(i) 20.2203(a)(3)(ii)

So.73(a)(2)(iii) 73.71

;M 20.2203(a)(2)(ii) 20.2203(a)(4) 50.73(a)(2)(iv)

OTHER

.jd 20.2203(a)(2)(iii) 50.36(c)(1) 50.73(a)(2)(v)

Specify in Abstract below r in NRC Form 368A 20.2203(a)(2)(iv) 50.36(c)(2) 50.73(a)(2)(vii)

UCMCONTACT FOR THIS LER (121 NAME TELEPHONE NUMBER (include Area Code)

J. C. Allen, Senior Engineer (217) 935-8881, Extension 4046 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE

SYSTEM COMPONENT M ANUF AC TURER PEPORTABLE

CAUSE

SYSTEM COMPONENT M ANUF ACTURER REPORTABLE TO NPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14)

EXPECTED MONTH DAY YEAR SUBMISSION DATE (15)

YES X

NO (if yes, complete EXPECTED SUBMISSION DATE).

ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)

With the plant in COLD SHUTDOWN and the sixth refueling outage in progress, a review of instrument accuracy for compliance with the Technical Specifications (TS) was being performed. During the review it was determined that Clinton Power Station procedure 9061.09, which satisfies TS Surveillance Requirement (SR) 3.6.1.3.6 governing Main Steam Isolation Valve (MSIV) closure time testing, was not adequate because it did not account for full valve travel.

Faulty data from CPS 9061.09 was also used in procedure 9432.30 to satisfy TS SR 3.3.6.1.7 for MSIV system response time testing. Consequently, there have been several instances since April 26, 1988, where the MSIV valve and system closure times have not been within TS SR 3.6.1.3.6 and TS SR 3.3.6.1.7.

The cause of this event was determined to be procedural inaccuracy.

Corrective actions include revising CPS 9061.09 to account for full valve travel, verifying MSIV operability before plant start up, and training plant operators on the MSIV limit switch configuration and position indication.

9706250245 970618 PDR ADOCK 05000461 S

PDR NF.C FOHM 366 (4 95)

i

• U.S. NUCLEAR REGULATC RY COMMISSION 14-9 6)

LICENBEE EVENT REPORT (LER) i TEXT CONTINUATION l

FAc1LITY NAME fil DOCKET LER NUMBER tm PAGE f 31 YEAR SEQUENTIAL W SON NUMMR Clinton Power Station 05000461 97 014 00 2

OF 4

TEXT (If more space is required, use additionalcopies of NRC Form 366A) til)

DESCRIPTION OF EVENT

On May 20, 1997, with the plant in Mode 4 (COLD SHUTDOWN) with reactor coolant temperature l

b31ng maintained between 100 and 120 degrees Fahrenheit and reactor pressure at zero pounds per square inch, the sixth refueling outage (RF-6) was in progress. A review of instrument cccuracy for compliance with the Technical Specifications was being performed in response l

to cn Information Notice received from the Institute of Nuclear Power Operations (INPO)

Nuclear Network. This review included evaluating the use of a digital stop watch (KI) to me:Iure Main Steam Isolation Valve (MSIV) (ISV) closure time in accordance with CPS 9061.09, "MS/FW System Valve Operability (Cold Shutdown)," and TS SR 3.6.1.3.6.

MSIV cloture time testing in accordance with TS SR 3.6.1.3.6 is required to be performed every sighteen months.

During the investigation it was noted that remote indicating lights located on a panel in th] MCR were used for time testing MSIVs. Each main steam line at CPS has two redundant MSIVs, inboard and outboard. There are two indicating lights for each valve. One of the indicating lights is red and is lit when the valve is ten (10) percent open to one-hundred (100) percent open.

The other indicating light is green and is lit when the valve is nincty (90) percent open to fully closed. Control room operators time MSIV closure from l

wh;n the valve switch is turned, to when the red open light on the MCR panel extinguishes Gt the 90 percent closed position.

CPS procedure 9061.09 requires timing the valve to full clocure, therefore, Condition Report 1-97-05-237 was initiated.

An investigation into this condition concluded that since issuance of the original CPS 9061.09, full MSIV closure has not been accurately measured as required by TS SR 3.6.1.3.6.

Further investigation identified that the incorrect data obtained from performing CPS 9061.09 was also used in CPS 9432.30, "MSIV Isolation System Response Time Test".

This procedure tests instrumentation response time associated with MSIV automatic trip functions to fulfill TS SR 3.3.6.1.7.

The stroke times obtained in CPS 9061.09 are added to the instrument response times of the automatic trip functions to obtain an overall system icolation response time.

Due to incorrect data obtained from CPS 9061.09, system isolation rczponse times were also not accurately measured as required by TS SR 3.3.6.1.7.

A rsview of previous CPS 9061.09 data indicates that MSIV closure time has been recorded as high as five (5) seconds.

If a correction factor is applied to account for full valve I

trcvel, the actual time to closure was approximately 5.55 seconds, 0.55 seconds longer than allowed by the Technical Specification acceptance criteria. This estimate was derived by multiplying the recorded stroke time by 100 and dividing the product by 90.

To meet the mIximum stroke time permitted by TS SR 3.6.1.3.6 using this formula, an MSIV must have l

indicated closed by the red indicating light extinguishing on the MCR panel in 4.5 seconds i

or less. April 26, 1988, with the plant in Mode 4 (COLD SHUTDOWN), was the first of csvaral instances where recorded time measurements have not been within TS SR 3.6.1.3.6 and i

TS SR 3.3.6.1.7 acceptance criteria. These instances have affected four out of the eight MSIVs.-

l l

$U.S. NUCLEAR REGULATORY COMMISSION (4-95)

,e LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME fil DOCKET LER NUMRF5t (H)

PAGE13)

YEAR SEQUENTIAL REVISION NUMBER NUMBER Clinton Power Station 05000461 97 014 00 3

OF 4

1 TEXT (If more space is required, use additional copies of NRC Form 366A) til)

No automatic or manually initiated safety system response was necessary to place the plant in a safe and stable condition. No other equipment or components were inoperable at the ctart of this event to the extent that their inoperable condition contributed to this cvsnt.

CAUSE OF EVENT

Th2 cause of this event is attributed to procedural inadequacy.

CPS 9061.09 did not j

include an accurate method to time full valve travel.

Furthermora, Plant Operations l

personnel were not aware that the valve open indicating light extinguishes at the 90 percent closed position instead of the fully closed position. An investigation of this svent identified that the original version of CPS 9061.09 did not contain an accurate method to time full valve stroke. The author and reviewers of the original version of the procedure apparently did not recognize that the "close" valve position indicating light was cst to extinguish at the 90 percent closed and not the fully closed position.

l

CORRECTIVE ACTION

t I

i CPS 9061.09 will be revised to account for full valve travel. Operations personnel will be trained on the MSIV limit switch configuration and how it affects the position indicating lights in the MCR.

An engineering evaluation was performed on the most recent MSIV closure rscults performed May 20, 1997. The evaluation determined that one of the eight MSIVs did not meet TS requirements. This MSIV's stroke time will be adjusted and the valve will be ratested to verify TS operability before plant start up.

ANALYSIS OF EVENT

l This event is reportable under the provisions of 10CFR50.73(a)(2)(1)(B) due to failure to I

mest requirements of TS SR 3.6.1.3.6 and TS SR 3.6.6.1.7.

MSIV valve and system closure l

times did not meet the acceptance criteria of the Technical Specifications on several occasions since April 26, 1988. This condition went undetected because of deficiencies in CPS 9061.09.

An analysis of the safety consequences and implications identified that this sysnt was not safety significant. Each main steam line at CPS has two MSIVs. No occurrences of both MSIVs in a main steam line failing to meet the acceptance criteria of TS SR 3.6.1.3.6 during the same period were discovered during review of previous performances of surveillance test results. This confirms system isolation response time would have occurred within the criteria of TS SR 3.3.6.1 7 excluding a failure of an MSIV to close. Furthermore, an analysis of this event has determined that isolation during a main steam line rupture is the most limiting scenario for MSIV closure.

Closure time for this accident is based on dose to the general public. The projected dose increase accociated with the last 10 percent of MSIV travel time is inconsequential.

I 1

8[, NRC FORM 366A U.S. NUCLEAR REGULATORY COMMIS810N (4 95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FActitTY NAME fil DOCKET LER NUunsa (ii)

PAGE 13)

YEAR SEQUENTIAL REMSION BER NUMBER Clinton Power Station 05000461 97 014 00 4

OF 4

TEXT Ilf more space is required, use additional copies of NRC Form 366A) (17) l

ADDITIONAL INFORMATION

No equipment or component failed during this event.

l No similar events concerning inadequate MSIV stroke time testing have been reported in rccent history. Additional evaluation is continuing to ensure this situation does not i

l cxist for other stroke-timed valves.

For further information regarding this event, contact J. C. Allen, Senior Engineer, at (217) 935-8881, extension 4046.

l I

l l

l i

t l

l l

I l

t I

f l

i

,