Information Notice 1979-32, Separation of Electrical Cables for HPCI and ADS

Separation of Electrical Cables for HPCI and ADS

ML070220250
Person / Time
Site:	05000000
Issue date:	12/21/1979
From:	NRC/IE
To:
References
IE-79-032, NUDOCS 7910250511
Download: ML070220250 (3)

791/OZ5O 51/

UNITED STATES SSINS No.: 6870

NUCLEAR REGULATORY COMMISSION Accession No:

OFFICE OF INSPECTION AND ENFORCEMENT 7910250511 WASHINGTON, D.C. 20555 December21, 1979 IE Information Notice No. 79-32

SErARATION OF ELECTRICAL CABLES FOR HPCI AND ADS

This notice contains information on boiling water reactors (BWR's) regarding the

routing of high pressure coolant injection (HPCI) system and automatic depres- surization system (ADS) cables in the same cable tray. Such routing violates

design criteria for separation of these safety systems. This potential cable

separation problem for BWR's is highlighted as a result of our review of recent

Licensee Event Reports (LER's): Hatch Units I & 2, Brunswick Unit 1, and

James A. FitzPatrick (See references for LER identification).

Des(ciption of Circumstances:

The Hatch LER's state that tht NSSS supplier (Genera7 Electric) contacted plant

management about possible irregularities in cable separation between HPCI and ADS.

Plant engineering personnel subsequently confirmed that separation criteria per

design notes were not met because HPCI ;ystem inboard steam supply isolation

valve cables were routed with ADS contro& cables. The architect-engineer (AE)

was notified of the HPIC/ADS cable separation problem and they are formulating a

design chinge to provide for proper cable separation. Other; immediate corrective

action was not provided in the LER.

The Brunswick LER states that cables for the HPCI system steam sipply inboard

isolation valve are located in sections of cable tray containing ADS cables. Also, their analysis of those cables revealed that if the isolation valve were in the

wrong position, then a failure at a tray section containing these cables might

result in a combination of cable failures which could impair the operability of

both the HPCI ,nd ADS systems. The problem is common to both units at Brunswick.

The AE, United Engineers and Constructors, is said to be preparing plant modifi- cations to provide sufficient isolation of HPCI and ADS cables. The licensee

stated that a review of emergency core cooling systems (ECCS) and their primary

containment isolation valves is being performed to verify that no other cable

separation problems exist. Also, the cable separation criterion for HPCI and ADS

systems is to be redefined in the cable s.eparation specifications to prevent

future recurrences of this event.

The FitzPatrick plant staff was informed of the HPCI/ADS cable routing problem by

the AE, Stone and Webster, following a fire hazard analysis conducted by the AE.

Six cables which could affect the control of the steam supply inboard isolation

valve for the HPCI system are located in the same cable trays as some ADS cables.

Initial corrective action by the licensee to preclude spurious closure of the HPCI

system inboard steam supply isolation valve was to de-energize the valve by

racking out the breaker. In addition, for purposes of primary containment

isolation, the outboard valve was maintained in its normal, closed position

IE Information Notice No. 79-3Z DecemberVJ, 1979 and checked daily. However, re-evaluation of the initial corrective action- indicated the preferred method of assuring operability of both the ECCS and

primary containment isolation functions would be to provide additional protection

against a fire which might Involve cables of both the HPCI and ADS, and to restore

the inboard isolation valve to a fully operable condition. Accordingly, FitzPatrick initiated an hourly patrolling fire watch and restored the inboard

isolation valve to a fully opera;,?* :ndition. The hourly patrolling fire watch

parallels that required by Techniical Specifications when early warning protection

against a potential fire must be taken due to inadequate or inoperable fixed

detection systems.

The FitzPat-ick plant staff was also informed by Stone and Webster that other

(third party) caoles (not identified in the LER) could affect the operation

of the inboard isolation valve for the [PCI steam supply due to their proximity

to both HPCI and ADS cables. The licensee has decided to re-route the cables

of concern to correct both problems, and states that a preliminary design

modification has been completed.

Conclusions

Our review indicates that lack of separation of HPCI and ADS cables is a possible

generic -roblem for all BWR4's and that earlier designs may also be affected.

Permanent resolution of this problem, corrective action in the meanwhile, and

separation from other systems such as RCIC or i-solation condenser are under

consideration by the NRC. It is anticipated that further NRC evaluations will

result in issuance of an IE Circular, Bulletin, or NRR genet ic letter in the

near future which will recommend or request specific applicant or licensee

actions.

This Information Notice is provided to inform licensees of a possible significant

matter. If you have questions regarding this matter, please contact the Director

of the appropriate NRC Regional Office.

No written response to this Information Notice is required.

References:

1. Hatch 1, LER #79-056/0]T-0, dated September 11, 1979

2. Hatch 2, LER #79-098/DIT-O, dated September 11, 1979

3. Brunswick 1, LER #79-068/OIT-0, dated October 9, 1979

4. FitzPatrick, LER #79-056/OIT-0, dated October 9, 1979

5. FitzPatrick, LER #79-056/OIT-1, dated November 19, 1979

IE Information Notice No. 79-32 Ern closure

December 21, 1979

RECENTLY ISSUED

IE INFORMATION NOTICES

Information Subject Date Issued To

Notice No. Issued

79-31 Use of Incorrect Amplified 12/13/79 All holders of power reactor

Response Spectra (ARS) OLs and CPs

79-30 Reporting of Defects and 12/6/79 All power reactor facilities

Noncompliance, 10 CFR Part 21. holding OLs and CPs and

vendors inspected by LCVIP

79-29 Loss of NonSafety-Relatcd 11/16/79 All power reactor facilities

Reactor Coolant System holding OLs or CPs

Instrumentation During

Operation

79-28 Overloading of Structural 11/16/79 All power reactor facilities

Elements Due to Pipe Support with an OL or CP

Loads

79-27 Steam Generator Tube 11/16/79 All power reactor facilities

Ruptures At Two PWR holding OLs and CPs

Facilities79-12A Attempted Damage To New 11/9/79 All Fuel Facilities, Fuel Assemblies research reactors, and

power reactors with an

OL or CP

79-26 Breach of Containment 11/5/79 All power reactor facilities

Integrity holding OLs and CPs

79-25 Reactor Trips At Turkey 10/1/79 All power facilities with

Point Units 3 And 4 an OL or a CP

79-24 Overpressurization Of 10/1/79 All power reactor facilities

Containment Of A PWR Plant with a CP

After A Main Steam Line

Break

79-23 Emergency Diesel Generator 9/26/79 All power reactor

Lube Oil Coolers facilities holding OLs

and CPs

79-22 Qualification of Control. 9/14/79 All power reactor

Systems facilities with

operating licenses

and construction permits.