Information Notice No. 84-16: Failure of Automatic Sprinkler System Valves to Operate
SSINS No.: 6835
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
All nuclear power reactor facilities holding an operating license (OL) or a
construction permit (CP).
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
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
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
1. Drawing of Automatic Model C Valve
2. List of Recently Issued IE Information Notices
Page Last Reviewed/Updated Wednesday, March 24, 2021