ML19260C610
| ML19260C610 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 12/21/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 8001080098 | |
| Download: ML19260C610 (1) | |
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SUITE 202, WALNUT CREE K PLAZA WALNUT CREE K, CALtFORNI A 94596 December 21, 1979 Docket flo. 50-312 Sacramento Municipal Utility District P. O. Box 15830 Sacramento, California 95813 Attention: Mr. John J. Mattimoe Assistant General Manager Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter. No specific action or response is requested at this time. However, we anticipate that further NRC evaluations will result in issuance of an IE Circular, Bulletin, or NRR Generic Letter in the near future which will recommend or request specific cpplicant or licensee actions.
If you have any questions regarding the matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely, w~
[R.H.EHgelken Director
Enclosures:
1.
IE Information Notice No. 79-32 2.
. List of Recently Issued Information Notices cc w/ enclosures:
R. J. Rodriguez, SMUD L. G. Scnwieger, SMUD 1702 028 099 s oo108g rg
UtlITED STATES SSIriS tio.: 6870 14UCLEAR REGULATORY COMMISSI0ft Accession tio:
0FFICE OF IriSPECTI0tl AtlD EriFORCEMEtiT 7910250511 WASHIllGT0ti, D.C.
20555 December 21, 1979 a
IE Information tiotice tio. 79-32 SEPARATION 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 separaticn of these safety systens.
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 1 & 2, Brunswick Unit 1, and James A. FitzPatrick (See references for LER identification).
Description of Circumntances:
The Hatch LER's state that the NSSS supplier (General 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 system inboard steam supply isolation valve cab:es were routed with ADS control cables.
The architect-engineer (AE) was notified of the HPIC/ ADS cable separation problem and they are formulating a design change 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 supply inboard isolation valve are located in sections of cable trays 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 and ADS systems. The problem is common to cotn units et orunswick.
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 separation 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 maintaired in its normal, closed position 1702 029
IE Information Notice No. 79-32 December 21, 1979 Page 2 of 2 and checked daily.
However, re-evaluation of the initial corrective action indicated the preferred nethod of assuring operability of both the ECCS and primary containnent isolation functions would be to provide additional orotection 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 operable condition. The hourly patrolling fire watch parallels that required by Technical Specifications when early warning protection against a potential fire must be taken due to inadequate or inoperable fixed detection systems.
The FitzPatrick plant staff was also inforned by Stone and Webster that other (third party) cables (not identified in the LER) could affect the operation of the inboard isolation valve for the HPCI 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 conpleted.
Conclusions Our review indicates that lack of seoaration of HPCI and ADS cables is a possible generic problem for ell BWR4's and that earlier designs may also be affected.
Permanent resolution of this problem, corrective action in the reanwhile, and separation from other systems such as RCIC or isolation condenser are under consideration by the flRC.
It is anticipated that further flPC evaluations will result in issuance of an IE Circular, Bulletin, or NRP, generic letter in the near future which will recommend or request specific applicant or licensee act!cns.
This Information Notice is provided to inform licensees of a possible significant matter.
If you have questions regarding this matter, please contact thr Director of the appropriate NRC Regional Office.
No written response to this Information Notice is required.
References:
1.
Hatch 1, LER #79-056/0IT-0, dated September 11, 1979 2.
Hatch 2, LER #79-098/0lT-0, dated Septenber 11, 1979 3.
Brunswick 1, LER #79-068/0IT-0, dated October 9, 1979 4.
FitzPatrick, LER #79-056/0IT-0, dated October 9, 1979 5.
FitzPatrick, LER #79-056/0lT-1, dated flovember 19, 1979 1702 030
?E Information NoticezNo. 79-32 Enclosure Decedber 21, 1979 RECENTLY ISSUED IE INF0PNAT10N NOTICES Informatiun 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 MonSafety-Related 11/16/79 All power reactor facilities Reactor Coolant System holding Ols or cps Instrunentation 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 Facili ties79-12A
'ttenpted Damage To New 11/9/79 All Fuel Facilities, Fuel Asserblies 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 Containmentz0f 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.
1702 031