United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 84-68: Potential Deficiency in Improperly Rated Field Wiring to Solenoid Valves

                                                          SSINS No.: 6835  
                                                          IN 84-68         

                               UNITED STATES 
                       NUCLEAR REGULATORY COMMISSION 
                    OFFICE OF INSPECTION AND ENFORCEMENT 
                            WASHINGTON, DC 20555 

                              August 21, 1984 

Information Notice No. 84-68:   POTENTIAL DEFICIENCY IN IMPROPERLY RATED 
                                   FIELD WIRING TO SOLENOID VALVES 

Addressees: 

All holders of a nuclear power reactor operating license (OL) or 
construction permit (CP). 

Purposes: 

This notice is provided to inform recipients of a potential deficiency 
involving field installed electric cables with low temperature rated 
insulation that are terminated inside solenoid valves with high temperature 
valve body housing. A cable insulation breakdown may prevent safety-related 
solenoid valves from operating properly. It is expected that recipients will
review the information for applicability to their facilities and consider 
actions, if appropriate, to preclude a similar problem occurring at their 
facilities. However, suggestions contained in this information notice do not
constitute requirements and, therefore, no specific action or written 
response is required. 

Description of Circumstances: 

On March 19, 1984, Bechtel Power Corporation reported under 10 CFR 21 a 
design deficiency in field-run cables to Valcor solenoid valves at Callaway 
and Wolf Creek Nuclear Plants. A representative of the licensee, the 
Standardized Nuclear Unit Power Plant System (SNUPPS) Organization, 
investigated the problem as discussed above and issued a report on April 13,
1984, under the provisions of 10 CFR 50.55(e). The details of the report are
summarized below. 

The field-run cables are terminated inside a totally enclosed valve body, 
housing a large energized solenoid. The configuration is such that the 
terminal boards are located within the valve body above the solenoid. No 
means is provided to dissipate the heat generated by the solenoid. 

Callaway documented the deficiency involving degraded insulation on 
field-run cables connected to Valcor solenoid valves. The valve 
qualification documents revealed that the ambient temperatures inside the 
valve body can approach a maximum of 250-280 F when the valves are 
energized for an extended period of time. The field-run cable, used to 
connect the valve into the plant control system, has an insulation 
temperature rating of 90 C (144 F). Using this lower temperature 
insulation cable within a high ambient temperature valve body will cause the 
cable insulation to degrade prematurely and may result in cable insulation 
failure and ultimately compromise the safety function of the valve. 

8408210142  
.

                                                         IN 84-68         
                                                         August 21, 1984  
                                                         Page 2 of 2      

Wolf Creek and Callaway each have 37 Class 1E Valcor valves that are 
affected by this deficiency. An additional 6 non-Class 1E Valcor valves are 
also affected. The safety related valves are in the following systems: 

          Containment hydrogen control 
          Nuclear sampling 
          Steam generator blowdown 
          Residual heat removal 
          Containment purge 
          Fuel building HVAC 

Other types and makes of valves may be affected at other nuclear sites. 

A SNUPPS followup report dated May 10, 1984 indicated that further 
investigation identified valves other than Valcor solenoid valves that have 
similar deficiencies as described above.  These are: 

     1)   Twenty Target Rock solenoid valves furnished under the (NSSS) 
          scope for use in safety-related systems 
     2)   Two ASCO solenoid valves on each of 12 condenser dump valves (not 
          safety-related) 
     3)   One ASCO solenoid valve on each of two control room heating, 
          ventilation, and air conditioning (HVAC) water control valves 

Corrective Action: 

SNUPPS implemented design changes to replace a portion of the field-run 
wiring with qualified high-temperature wiring with 200 C rated 
insulation. The high-temperature wire is used as a jumper from the terminal 
block inside the valve body to a splice box located approximately 5 to 10 
feet from the valve. The field-run cable is spliced into the 
high-temperature wire in the splice box, thus, there is no low-temperature 
cable inside of the valve body. 

No written response to this information notice is required. If you have any 
questions about this matter, please contact the Regional Administrator of 
the appropriate NRC regional office or this office. 


                                   Edward L. Jordan, Director 
                                   Division of Emergency Preparedness 
                                     and Engineering Response 
                                   Office of Inspection and Enforcement 

Technical Contact:  W. Laudan, IE 
                    (301) 492-9759 

Attachment:    List of Recently Issued IE Information Notices
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