IE Circular No. 80-09, Problems with Plant Internal Communications Systems

                                                            SSINS No.: 6830 
                                                            Accession No.: 
                                                            8002280663

                                UNITED STATES
                        NUCLEAR REGULATORY COMMISSION
                    OFFICE OF INSPECTION AND ENFORCEMENT
                           WASHINGTON, D.C.  20555

                               April 28, 1980

                                                     IE Circular No. 80-09 

PROBLEMS WITH PLANT INTERNAL COMMUNICATIONS SYSTEMS 

Description of Circumstances at the Kewaunee Power Plant: 

On January 17, 1980, the Kewaunee Nuclear Power Plant lost offsite power to 
its 4160V non-safeguards buses.  Since the system used for internal 
communications, paging and evacuation alarm purposes (Gai-tronics) was 
powered from a non-safeguards bus, plant communications were degraded during 
the outage.  This degraded condition persisted until power was restored to 
the affected bus thru an emergency safeguards bus.  While in the degraded 
mode, the licensee used two-way portable radios for internal communications.  
The radios performed satisfactorily, per se; however, when transmitting in 
the vicinity of certain electronic equipment, they induced false signals 
into the electronic equipment. 

Description of Circumstances at the Davis-Besse Power Station: 

On October 15, 1979, the Davis-Besse Power Station lost all offsite power. 
During the period when offsite power was not available, the licensee noted 
that the internal three digit telephones (GTE) would not function.  In 
addition, the NRC "Red Phone" was subsequently reported to have been out of 
service.  Other licensee phone systems (Gai-tronics and the outside four 
digit Ohio Bell phones) did work. 

Following this event, the licensee provided emergency power to its phones 
and the NRC took action through AT&T to provide emergency power to all Red 
Phones. (Note:  Although the communications system at Davis-Besse was not 
designed to meet the single failure criterion, its FSAR states that the main 
internal communications system is supplied by two redundant power feeders 
from the uninterruptable instrumentation distribution panels.) 

RECOMMENDED ACTION FOR LICENSEES AND HOLDERS OF CONSTRUCTION PERMITS 

All licensees of nuclear power reactor and holders of construction permits 
should be aware of the potential problems described above.  Because of the 
generic implications of the above problems, it is recommended that the 
following actions be considered: 

1.   Determine the source of power for plant internal communications 
     systems; 

2.   Upgrade the internal communications systems to assure operability 
     during the loss of offsite power or other foreseeable events; 
.

IE Circular No. 80-09                                       April 28, 1980 
                                                            Page 2 of 2 

3.   Determine whether any plant electronic equipment may be adversely 
     affected by portable radio transmissions.  This determination should 
     include, but no be limited to, the computer system, electro-hydraulic 
     system, and nuclear instrumentation system; and 

4.   Instruct employees on the use radios in areas susceptible to electro 
     magnetic interference. 

No written response to this Circular is required; however, if additional 
information regarding these matters is required, contact the Director of the
appropriate NRC Regional Office.