United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 86-05, Supplement 1: Main Steam Safety Valve Test Failures and Ring Setting Adjustments

                                                     SSINS No: 6835       
                                                     IN 86-05, Supplement 1 

                                UNITED STATES
                           WASHINGTON, DC 20555

                              October 16, 1986

Information Notice No. NO 86-05, SUPPLEMENT 1:    MAIN STEAM SAFETY VALVE 
                                                  TEST FAILURES AND RING 
                                                  SETTING ADJUSTMENTS 


All nuclear power reactor facilities holding an operating license or a 
construction permit 


This notice is being provided as a supplement to Information Notice (IN) 
86-05 to inform licensees of additional experience with ring setting 
adjustments of main steam safety valves (MSSVs) It is expected that 
recipients will review the information for applicability to their facilities
and consider actions, if, appropriate, to preclude a similar problem from 
occurring at their facilities However, suggestions contained in this 
information notice do not constitute NRC requirements; therefore, no 
specific action or written response is required 

Description of Circumstances: 

Seabrook, 1985 (Synopsis) 

In the fall of 1984, Seabrook's MSSVs (manufactured by Crosby) were sent to 
Wyle Laboratories for testing The results of the tests showed that adequate
disc travel was not attainable with the factory-set ring settings Following
additional testing, the ring settings were adjusted from the factory 
settings to obtain the required disc travel 

Vogtle, 1986 

On May 14, 1986, Georgia Power Company informed the NRC that 5 of the 20 
Crosby MSSVs due to be installed on Vogtle 1 were tested to determine the 
appropriateness of their as-shipped ring settings (nozzle ring setting of 
+150 and guide ring setting of -45) The valve settings did not achieve 
specified relieving capacity The typical relieving flow was 75% of the 
specified value  Subsequently all 20 of the valves were shipped to the 
Crosby high-flow test facility to be tested and adjusted as required to 
achieve their design relief capacity Final ring settings are summarized in 
Attachment 1 Note that these settings in many instances differ considerably
from the as-shipped settings Unit 2 valves are due to be tested in the 


                                                     IN 86-05, Supplement 1 
                                                     October 16, 1986      
                                                     Page 2 of 2           

   Millstone 3, 1986 

On July 29, 1986 while inspecting the A-bank MSSVs, personnel found that the
upper and lower adjusting rings were not set to the vendor's (Dresser) 
recommended settings After an investigation, it was determined that the 
vendor had not reset the rings following functional testing because of a 
procedural inadequacy Millstone 3 personnel reset all rings to the 
recommended settings (Licensee Event Report 50/423-86/043) 

Susquehanna 1 and 2 

Pennsylvania Power and Light personnel recognized the 6R1O designation used 
by Seabrook to describe their valves (IN 86-05) as being the same as the 
Crosby safety/relief valves (SRVs) installed at Susquehanna Units 1 and 2; 
however, the designation 6R1O is not a model number, but the inlet, orifice,
and outlet size of the valve These SRVs are not the same model as the 
Seabrook or Vogtle valves, but they do have adjusting rings which determine 
the capacity and blowdown of the valves Because of this, the information in
IN 86-05 and this supplement may be applicable to boiling-water reactors 

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

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

Technical Contact:  Mary S Wegner, IE 
                    (301) 492-4511 

1   Summary of Final Rings Settings for Vogtle 1
2   List of Recently Issued IE Information Notices

Page Last Reviewed/Updated Friday, May 22, 2015