United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No.80-11 – Generic Problems with ASCO Valves in Nuclear Applications Including Fire Protection Systems

                                                           SSINS No. 6870  
                                                           Accession No.:  
                                                           7912190684      

                                UNITED STATES
                       NUCLEAR REGULATORY COMMISSION 
                    OFFICE OF INSPECTION AND ENFORCEMENT 
                           WASHINGTON, D.C. 20555 
                                     
                              March 14, 1980  

                                           Information Notice No. 80-11 

GENERIC PROBLEMS WITH ASCO VALVES IN NUCLEAR APPLICATIONS INCLUDING FIRE 
PROTECTION SYSTEMS 

Description of Circumstances: 

Enclosure 1 is a Recall Notice from The Viking Corporation, dated July 16, 
1979 that identifies ASCO valves used in certain Viking fire protection 
equipment that could fail. 

Licensees should review their fire protection system components to determine
if the equipment identified in the Viking Recall Notice is in their 
facility. If the identified equipment is installed in the fire protection 
system, then the modifications specified in the Recall Notice should be made 
and tested for proper operation. The requirements of the technical 
specifications or any other licensee commitment should be complied with when 
a fire protection system is disabled. 

South Carolina Electric and Gas Company (Virgil C. Summer Nuclear Station) 
reported to the NRC on October 24, 1979, a potential significant deficiency 
regarding the effects of oil on elastomeric materials used in ASCO NP-1 
solenoid valves. Specifically, these valves utilize an ethylene propylene 
elastomer which expands or swells when brought into contact with oils, 
possibly causing valve failure. For this reason, ASCO specifies these NP-1 
solenoid valves for use in "oil free instrument air" systems. 

Although instrument air systems are "oil free" by design, installation 
instructions may specify the use of thread lubricants utilizing an oil base.
Thus, the potential exists for traces of this lubricant from threaded 
connections in the air system, in addition to traces of oil from the air 
compressors themselves, to come into contact with the elastomers in the 
solenoid valves. Degraded elastomers can cause the solenoid valve to fail by
sticking, swelling closed flow paths, or rupturing causing leakage across 
the seat or to atmosphere. Failure of the solenoid to function properly on 
an active valve could prevent a system from performing its required safety 
function. 

Some ASCO NP-1 solenoid valves are equipped with tags which state: 
"Important this valve is equipped with ethylene propylene elastomers which 
can be attacked by oils and greases. To be used for oil-free instrument 
quality air. Clean pipe threads of cutting oils." Care should be taken to 
use approved thread lubricants which do not contain oil for the installation 
of these valves. 
.

Information Notice No. 80-11                              March 14, 1980 
                                                             Page 2 of 2   

ASCO offers viton elastomers as an option for their NP-1 solenoid valves. 
The viton elastomers are not affected by oil or grease. Replacement kits of 
viton elastomers are available for the NP-1 solenoid valves from ASCO. It is
recommended that ethylene propylene elastomers found in Class IE qualified 
ASCO NP-1 solenoid valves be replaced with the viton kits. 

In addition, enclosed is a letter from EG&G (Enclosure 2) dated December 26,
1979 that provides the results of an LER review of failure of solenoid 
valves. 

This Information Notice provided information about a potential safety 
concern. No written response is required. If you desire additional 
information regarding this matter, contact the Director of the appropriate 
Regional Office. 

Enclosure: 
1. Viking Corporation Recall Notice 
2. EG&G Letter, Dearien to Tiller 
     dated December 26, 1979 

Page Last Reviewed/Updated Tuesday, November 12, 2013