United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 84-23: Results of the NRC-Sponsored Qualification Methodology Research Test on ASCO Solenoid Valves

                                                          SSINS No.: 6835  
                                                          IN 84-23         

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

                               April 5, 1984 

Information Notice No. 84-23:   RESULTS OF THE NRC-SPONSORED 
                                   QUALIFICATION METHODOLOGY RESEARCH TEST 
                                   ON ASCO SOLENOID VALVES 

Addressees: 

All nuclear power reactor facilities holding an operating license (OL) or 
construction permit (CP). 

Purpose: 

This information notice is provided as an early notification of a 
potentially significant event concerning the failure of two naturally aged 
Automatic Switch Company (ASCO) solenoid valves. These valves are ASCO 
models NP-8316 and NP-8344. The failure of these two naturally aged valves 
occurred during the LOCA/MSLB (Loss-of-coolant accident/main steam line 
break) simulation phase of a qualification methodology research test 
conducted by the Franklin Research Center (FRC). It should be noted that 
this information notice is not addressing the earlier concerns dealing with 
the Viton/EPDM material used in ASCO solenoid valves as described in 
previously published information notices. It is expected that recipients 
will review the information for applicability to their facilities and take 
appropriate action. A response is not required. 

Description of Circumstances: 

Recently the Nuclear Regulatory Commission (NRC), Office of Nuclear 
Regulatory Research (RES) sponsored a qualification methodology research 
test on seven ASCO solenoid valves. The test program was developed by FRC 
for the NRC. This research test program resulted in a number of failures 
which had not been experienced in previous qualification tests performed by 
the manufacturer. The FRC test specimens consisted of seven different valve 
models, of which five valve models were artificially aged, and two valve 
models were naturally aged. The natural aging which was done by the 
manufacturer, consisted of exposing the two test valve models in an air oven
at 140F (60C) for three years. The valves were pressurized with 
nitrogen and valve solenoids were continuously energized. 

The test program was patterned after the requirements of IEEE 323-1974, 
344-1975, 382-1980, and NUREG-0588, Rev. 1, with the exception that the two 
naturally aged valve models (model NP-8316-66E, and model NP-8344-A71E) were
not exposed to radiation preaging. All seven valves were subject to DBA 
radiation followed by LOCA/MSLB simulation. The specified temperature/ 



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                                                             IN 84-23      
                                                             April 5, 1984 
                                                             Page 2 of 3   

pressure profile for the simulated LOCA/MSLB exposure, and details of the 
FRC Solenoid valves test program and failure analysis can be found in 
NUREG/CR-3424 (published in November 1983.) 

Of the seven valve models that were tested, one passed and six failed during
the LOCA/MSLB test. The valve model which passed was artificially aged and 
had a metallic seat. Among the six valve models that failed, four models 
were artificially aged and two valve models were naturally aged. Naturally 
aged valve model NP-8344 failed after 14 minutes into the test, and 
naturally aged valve model NP-8316 failed after 2.75 hours into the test. 
Failure was defined as the inability of the valve to perform its function. 

Failure of naturally aged valve NP-8344 was attributed to the elastomer 
sticking to valve metallic parts. For naturally aged valve NP-8316, the 
failure was attributed to the cumulative degradation of the elastomer 
diaphragm. 

Discussion: 

The NRC staff has reviewed the FRC test results and has made the following 
observations: (1) the nature of the FRC test is a qualification methodology 
research test, which has allowed the valves to cycle at higher temperature 
during thermal aging, and (2) that the actual temperature profiles during 
both LOCA/MSLB transients were higher and longer in duration than 
recommended by industry standards. The NRC staff concluded that the failures 
of the FRC artificially-aged valves were inconclusive. However, the failure 
of the two naturally aged valves (models NP-8316 and NP-8344) during the 
recent FRC test cannot be discounted since they were not subjected to the 
same severe preconditioning as the artificially aged valves. 

Similar valve models as those naturally aged valves that failed the FRC test
were also tested by ASCO and Westinghouse (W) in 1982. The results of this 
test were documented in ASCO Report AQR-67368, Rev. O, March 1982 and WCAP 
8587 EQDP-HE2/HE5 Rev. 4, WCAP 8687 EQTR-HO2A/HO5 Rev. 2. In the ASCO/W 
test, model NP-8344 failed and model NP-8316 passed. Both the 1983 NRC/FRC 
test and the 1982 ASCO/W test were patterned after the same standards and 
since model NP-8316 failed the recent NRC/FRC test, the NRC staff considers 
that model NP-8316 may not be suitable for the environmental conditions and 
operating time requirements as reported in the aforementioned ASCO/W test 
reports. Westinghouse has been informed of these findings in a NRC letter 
dated December 23, 1983 from R. Vollmer (NRC) to E. P. Rahe (Westinghouse). 

Similar models of these same two valves were also tested in 1978 and 
reported in Isomedix AQS report number 21678/TR-Rev. A. Applications in 
which environmental conditions are enveloped by test conditions described in 
this Isomedix AQS 21678/TR-Rev. A report, are considered acceptable. 
.

                                                             IN 84-23      
                                                             April 5, 1984 
                                                             Page 3 of 3   

If you have any questions regarding 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 Contacts: N. B. Le, IE 
                    (301) 492-9673 

                    A. Masciantonio, NRR 
                    (301) 492-8205 

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