United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 85-47: Potential Effect of Line-Induced Vibration on Certain Target Rock Solenoid-Operated Valves

                                                            SSINS No.:  6835
                                                            IN 85-47

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

                                June 18, 1985

Information Notice No. 85-47:   POTENTIAL EFFECT OF LINE-INDUCED 
                                   VIBRATION ON CERTAIN TARGET ROCK 
                                   SOLENOID-OPERATED VALVES 

Addressees: 

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

Purpose: 

This information notice is to alert addressees that certain models of Target
Rock (TR) solenoid-operated valves have failed during environmental 
qualification testing. The analysis of the test failure suggests that line 
vibration induced by hydrodynamic force in piping and other forms of 
mechanical vibration may cause the loosening of the solenoid holddown nut of
those TR solenoid valves with design features similar to TR valve models 
that were tested. 

Because of the potential safety significance of line-induced and other 
vibrations on TR solenoid operated valves, it is suggested that recipients 
review this information for applicability to their facilities and consider 
actions, if appropriate, to preclude a similar problem occurring at their 
facilities. Suggestions contained in this notice do not constitute NRC 
requirements; therefore, no specific action or written response is required.

Description of Circumstances: 

On November 14, 1984, Arizona Public Services Company provided the NRC with 
a final report on a 10 CFR 50.55(e) reportable condition relating to 
qualification testing of certain TR solenoid-operated valves.  Four TR 
valves, procured by Combustion Engineering (CE) for use at Palo Verde 
Nuclear Generating Station Unit 3, were tested to the requirements of 
NUREG-0588, Category I. Test valves included two 1-inch TR valves, model 
77L-001 and two 2-inch TR valves, model 77L-003. The qualification test 
involved irradiation to 50 megarads, thermal aging at 260 F for 635 hours, 
mechanical cycling, vibrational aging to represent normal service vibration, 
seismic testing, and finally, testing in a simulated LOCA environment. The 
licensee reported that during the qualification testing, a number of 
anomalies were identified, and the test was discontinued when the test 
valves failed to function for different reasons during the seismic testing. 
CE and TR appraised the overall safety significance of the observed test 
anomalies for the licensee. They considered the failure of the valve to open 
on demand as a result of solenoid lead shorting caused by line-induced 
vibrational 


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                                                            IN 85-47       
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wear to be a common mode of failure that, in a seismic event, could 
potentially disable several redundant valves at the same time. This failure 
of the valve to open on demand is the only observed test anomaly considered 
to have significant generic safety implications and is the subject of this 
information notice. 

The root cause of the valve failure to open is attributable to the mechanism
used to secure the solenoid to the upper works assembly of the valve. The 
valves used at Palo Verde have a jam nut and a lock washer that are used 
together to secure the solenoid. If the upper works assembly is rotated 
during valve handling or installation, the jam nut can become loose, 
allowing axial rotation of the coil. As a corrective action, the licensee 
has stated in its latest report to the NRC that existing TR valves Models 
77L-0001 and 77L-003 are being upgraded. The upgrading includes a complete 
factory refurbishment of the valves with potting of the coil into the 
solenoid housing. The potting will prevent differential movement between the 
coil and housing to preclude lead wire abrasion during line-induced 
vibration. 

Target Rock Corporation also has reported that the following TR valve models
and plants may be affected by line-induced vibration: 

Valve Models                            Power Plants

72A-001/002/003/004/005/007             Monticello Nuclear Power Plant
72V-001                                 Duane Arnold Energy Center 
73E-002                                 Trojan Nuclear Plant
75G-002/003/008/009/013                 San Onofre Nuclear Generating Stati
75GG-001                                Grand Gulf Nuclear Station
75KK-204/207                            Susquehanna Steam Electric Station
76B-002/024/039/040/041/042/043/044     Midland 

TR has made the recommendation to the NRC that the utilities for the above 
listed power plants consider performing a review of safety-related systems 
that incorporate the above listed solenoid valves to determine if solenoid 
locking devices are installed on their valves. TR recommends that locking 
devices for the listed valves be installed per TR Service Bulletin 8302 
(attached), if they have not already been installed and the potential for 
line-induced vibration exists. (Note: the locking device of Service Bulletin
8302 is different from the potting mechanism used for the Palo Verde 
solenoids.)  


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                                                            IN 85-47       
                                                            June 18, 1985  
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No specific action or written response is required by this information 
notice. 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 Contact:  N. B. Le, NRR 
                    (301) 492-9686 

                    G. Hubbard, IE 
                    (301) 492-9759 

Attachments: 
1.   Target Rock Service Bulletin 8302 
2.   List of Recently Issued IE Information Notices
Page Last Reviewed/Updated Tuesday, November 12, 2013