United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No.: 79-32, Separation of Electrical Cables for HPCI and ADS

IN79032 

                             December 18, 1979 

MEMORANDUM FOR:     B. H. Grier, Director, Region I 
                    J. P. O'Reilly, Director, Region II 
                    J. G. Keppler, Director, Region III 
                    K. V. Seyfrit, Director, Region IV 
                    R. H. Engelken, Director, Region V 

FROM:               Norman C. Moseley, Director, Division of Reactor  
                      Operations Inspection, Office of Inspection and   
                      Enforcement 

SUBJECT:            Information Notice No. NO.:  79-32, SEPARATION OF 
                    ELECTRICAL CABLES FOR HPCI AND ADS 

The subject document is transmitted for issuance on December 21, 1979. The 
Information Notice should be issued to all power reactor facilities holding 
operating licenses and construction permits. 

Also enclosed is a draft copy of the transmittal letter. 

                                        Norman C. Moseley, Director 
                                        Division of Reactor Operations 
                                          Inspection 
                                        Office of Inspection and Enforcement

Enclosures:
1.   Draft Transmittal Letter
2.   IE Information Notice
          No. 79-32

CONTACT:  W. R. Mills, IE 
          49-28180 
.

(Transmittal letter for Information Notice No. 79-32 to each holder of an 
NRC Operating License and Construction Permit.) 

                                            Information Notice No. 79-32 

Addressee: 

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 applicant or licensee 
actions. If you have any, questions regarding the matter, please contact the 
Director of the appropriate NRC Regional Office. 

                                        Sincerely, 


                                        Signature 
                                        (Regional Director) 

Enclosure:
1.   IE Information Notice
       No. 79-32
2.   List of Recently Issued
       Information Notices 
.

                              UNITED STATES                SSINS No.: 6870 
                       NUCLEAR REGULATORY COMMISSION        Accession No:  
                   OFFICE OF INSPECTION AND ENFORCEMENT     7910250511     
                          WASHINGTON, D.C. 20555 

                             December 21, 1979 

                                            Information Notice No. 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 
depressurization 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 1 & 2, 
Brunswick Unit 1, and James A. FitzPatrick (See references for LER 
identification). 

Description of Circumstances: 

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 cables 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 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 and ADS systems. The 
problem is common to both units at Brunswick. The AE, United Engineers and 
Constructors, is said to be preparing plant modifications 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 
maintained in its normal, closed position 
.

                    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 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 patrol 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 informed 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 completed. 

Conclusions 

Our review indicates that lack of separation of HPCI and ADS cables is a 
possible generic problem 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 isolation 
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 
generic 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/OIT-O, dated September 11, 1979 
2.   Hatch 2, LER #79-098/OIT-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

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