ML20085L797

RO 50-267/75/2:insp of Steam/Water Dump Valves Revealed That Portions of Electrical Conduit Runs to Valves Violated Loop & Bus Segregation Criteria.Caused by Improper Installation. Cables,Switches,Solenoids & Junction Boxes to Be Modified

ML20085L797
Person / Time
Site:	Fort Saint Vrain
Issue date:	01/14/1975
From:	Swart F PUBLIC SERVICE CO. OF COLORADO
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
RO-50-267-75-2, NUDOCS 8311020459
Download: ML20085L797 (7)

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January 14, 1975 ..

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4 Mr. E. Morris toward, Director Directorate of Regulatory Operations ~

Region IV, USAEC P. O. Box 5039 White Setticaant, Texas 76108

Dear Mr. Howard:

REF: Facility Operating License No. DPR-34 Docket :To. 50-267 Enclosed please find a copy of Unusual Event No. 50-267/74/2, cub:2itted per the requirenents of the Technical Specifications. ,

Very truly yours, Frederic E. Svart Sup.crintendent !'uclear Froduction Fort St. Vrnin liucicar Cencrating Station (cc: Mr. Angelo Gianbusso/ . .

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. REPORT DATE: January 6, 1975 -

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.Pzga 1 UNUSUAL EVENT, .

EVENT DATE: December, 1974 FORT ST. VRAIN NUCLEAR GENERATING STATION PUBLIC SERVICE COMPANY OF COLOR /WO P. O. BOX 161 PLATTEVILLE, COLORADO 80651 REPORT NO.'50-267/74/2 Final IDENTIFICATION OF OCCURRENCE :

An electrical inspection of the steam / water dump valves (HV's 2215 through 2218) resulted in the discovery that certain portions of the electrical ~

conduit runs to the valves violated loop and bus segregation criteria. .

A more thorough inspection of all valves having power supplies from both non-interruptible instrument buses led to the discovery that many of these valves also had segregation problems. ,

This is identified as an unusual event in accordance with Technical Specif-ication AC 7-6c.2. .

CONDITIONS PRIOR To acct!RRENCE: Steady State Power Routine Shutdown Hot Shutdown Routine Load Change X Cold Shutdown Other (specify)

Refueling Shutdown Routine Startup' The major plant parameters at the time of the event were as follows:

Power PTR,- 0 MWth

. ELECT 0 MWe .

Secondary' Coolant Pressure 'O ' .P.SIG

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. Temperature O- *F' Flow 0 f/hr Primary Coolant Pressure O PSIG

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Temperature ~100 '*F Core Inlet

'100 *F' Core Outlet S

- Flow 0 #/hr.

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Page 2 DESCRIPTION OF -

OCCURRENCE:

Some of the limit switches that are installed on the steam / water dump valves are used in the control circuitry of valves in the other loop. The power supply cables-associated with these switches were installed in the same

conduit, which violates Bus 1/ Bus 2 non-interruptible bus segregation criteria and loop segregation. .

The minimum separation distance criteria was violated on a few valves that are supplied by both non-interruptible buses.

The solenoid controls on some valves are supplied by both non-interruptible

, buses. The flexible cables to the solenoids do not meet segregation criteria.

APPARENT CAUSE OF OCCURRENCE: Design Unusual Service Cond.

Including Environ.

Manufacture Component Failure X Installation /Const. Other (specify)

Operator -

4 Procedure

. ANALYSIS OF .,

OCCURRENCE:

All valves having interlocks between the two loops and/or having power supplies from both non-interruptible buses were inspected for violations.

All valves found in violation were referred -to .tlue general contractor for review and modification. ,

CORRECTIVE -

ACCION: ,

All cables, switches, solenoids and junction boxes involved in this inspection have been modified or are in the process of being modified, to meet loop.and, bus segregation criceria. An audit will be performed by Public Service Compdny to ensure that all modifications ate correct and meet the criteria set forth in the applicable specifications.

FAILURE DATA / sit!ILAR REPORTED OCCURRENCES:

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- Page 3 PROGRAMMATIC IMPACT: ,.

None CODE IMPACT:

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Recommended: [ bb'  % Approved: .E q e, . . ofc 9 '

11. Larry Brey.

Frederic E. Swart-'

l [ Supt.NucicarProduction Superintendent-Operations Fort St. Vrain Nuclear Fort St. Vrain Nuclear Generating Station Generating Station ,

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1. . REPORT DATE: January'6, 1975 UNUSUAL EVENT 4'

EVENT DATE: December, 1974

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FORT ST. VRAIN NUCLEAR GENERATING STATION '[ ff

'O PUBLIC SERVICE COMPANY OF COLORADO P. O. BOX 361 ,

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REPORT NO. 50-267/74/2 ., , . , bn

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IDENTIFICATION OF

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OCCURRENCE:

An electrical inspection of the steam / water dump valves (l!V's 2215 through 2218) resulted in the discovery that certai(portions of the ciectrical conduit runs to the valves violated loop and bus segregation criteria. )

A more thorough inspection of all valves having power supplies from both non-interruptible instrument buses led to the discovery that many of these valves also had segregation problems.

This is identified as an unusual event in accordance with Technical Specif-

- ication AC 7-6c.2.

CONDITIONS PRIOR Rm.itine Shutdown TO OCCURRENCE: Steady State "owcr Hot Shutdown Routine Load Change X Cold Shutdown Other (specify)

Refueling Shutdown Routine Startup' The major plant parameters at the time of the event were as follows:

Power PTR, O Wth ELECT 0- We Secondary Coolant Pressure O PSIG Temperature 0 *F Flow 0 #/hr Primary Coolant Pressure O PSIG Temperature ~100 *F Core Inlet

'100 *F Core Outlet Flow 0 f/hr.

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DESCRIPTION OF -

OCCURRENCE :

Some of the limit switches that are installed on the steam / water dump valves are used in the control circuitry of valves in the other loop. The power supply cables associated with these switches were installed in the same

-conduit, which violates Bus 1/ Bus 2 non-interruptible bus segregation criteria and loop segregation.

The minimum separation distance criteria was violated on a few valves that are supplied by both non-interruptible buses.

The solenoid controls on some valves are supplied by both non-interruptible buses. The flexible cables to the solenoids do not meet segregation criteria.

APPARENT CAUSE OF OCCURRENCE: Design Unusual Service Cond.

-Including Environ.

Manufacture Component Failure X Installation /Const. Other (specify)

Operator Procedure ANALYSIS OF .,

OCCURRENCE:

All valves having interlocks between the two loops and/or having power supplies from both non-interruptible buses were inspected for violations.

All valves found in violation were referred to the general contractor for review and codification.

CORRECTIVE i ACTION:

t All cables, switches, solenoids and junction. boxes involved in this inspection

, have been codified or are in the process of being modified, .to- meet loop and bus segregation criteria. An audit will be performed by Public Service Company to ensure that all modifications are correct and meet the criteria set forth in the applicable specifications.

FAILURE DATA /SIMILAR REPORTED OCCURRENCES:

None

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1- PROGRAFDIATIC IMPACT:

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None

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Recocunended : 'bbb'f - M Approved .mu qo s* _ urn

11. Larry Brcy l } /FredericE. Swart i Superintendent-Operations ) ' Supt. Nucicar Production Fort St. Vrain Nuclear Fort St. Vrain !!ucicar Cencrating Station Cencrating Station ,

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