United States Nuclear Regulatory Commission - Protecting People and the Environment

Information Notice No. 84-16: Failure of Automatic Sprinkler System Valves to Operate

                                                           SSINS No.:  6835 
                                                           IN 84-16        

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

                               March 2, 1984 

Information Notice No. 84-16:   FAILURE OF AUTOMATIC SPRINKLER SYSTEM 
                                   VALVES TO OPERATE 

Addressees: 

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

Purpose: 

This information notice provides notification of a problem involving the 
operational failure of deluge and pre-action fire protection water control 
valves, identified as Model C, manufactured by Automatic Sprinkler 
Corporation of America of Cleveland, Ohio. It is expected that recipients 
will review this information notice for applicability to their facilities. 
No specific action or response is required. 

Description of Circumstances: 

On September 4, 1983, Mississippi Power and Light (MP&L) Company's Grand 
Gulf Unit 1 was performing an operational test of an emergency 
diesel-generator when a fire involving the diesel engine occurred. The fire 
brigade arrived to find that the automatic deluge valve had not opened. The 
manual release failed to open the valve. A mechanic opened the actuator box 
cover and struck the actuation weight, forcing the clapper latch to release, 
permitting water spray from the sprinkler system to extinguish the fire. 
(See Attachment 1.) The valve was a 6-inch Model C, manufactured by 
Automatic Sprinkler Corporation of America of Cleveland, Ohio. (Reference 
LER 50-416/83-126.) 

During subsequent testing and examination, excessive friction was noted 
between the weight and the weight guide rod; bowing (0.005-inch) was 
observed in the weight guide rod; evidence of scoring was found in two 
locations on the rod's surface; the weight's upper guide collar had an 
inside diameter (ID) of 0.637 inch rather than the manufacturer's 
recommended minimum of 0.647 inch; and scoring was noted on the enclosing 
box along the path that the weight guide bushing traces during actuation. 

On December 5, 1983, a Model C valve for a pre-action sprinkler system 
protecting a diesel generator room failed to operate during a test at Grand 
Gulf. Similar roughness was found in its internals. A search of records 
uncovered  



8402090008 
.

                                                            IN 84-16       
                                                            March 2, 1984  
                                                            Page 2 of 2    

another event at Grand Gulf in which a Model C valve installed to protect a 
main transformer failed to open during a test in September 1979. 

The valve manufacturer has been notified of these failures and is evaluating
this problem to determine the action required. 

The licensee's preliminary investigation indicates that these failures may 
be related to the surface condition of the latch which holds the water 
clapper in the normally closed position. If the mating surfaces of the latch
and clapper are not smooth, the latch may fail to disengage when the 
actuation weight hits the latch arm. If the normal water system pressure 
applied to the clapper valve exceeds 140 psig, the problem becomes more 
acute. The water pressure at Grand Gulf is maintained at 140 psig. 

MP&L has sanded and trued the guide rod; reworked the ID of the weight's 
upper guide collar; lubricated the rod, latch pin, clapper hinge pin, and 
the enclosed box along the path of the weight guide bushings; temporarily 
increased the testing frequency of the valves; and revised the surveillance 
procedures to visually verify that the clapper has lifted and locked open 
following the test under normal system pressure. 

If you have any questions regarding this matter, 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:  M. S. Wegner, IE 
                    (301) 492-4511 

Attachments: 
1.   Drawing of Automatic Model C Valve 
2.   List of Recently Issued IE Information Notices
Page Last Reviewed/Updated Tuesday, November 12, 2013