Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
March 9, 1990
Information Notice No. 90-18: POTENTIAL PROBLEMS WITH CROSBY SAFETY
RELIEF VALVES USED ON DIESEL GENERATOR
AIR START RECEIVER TANKS
Addressees:
All holders of operating licenses or construction permits for nuclear power
reactors.
Purpose:
This information notice is intended to alert addressees to potential
problems with Crosby safety relief valves that could result in a loss of
starting air to the emergency diesel generators (EDGs). It is expected that
recipients will review the information for applicability to their facilities
and consider actions, as appropriate, to avoid similar problems. However,
suggestions contained in this information notice do not constitute NRC
requirements; therefore, no specific action or written response is required.
Description of Circumstances:
On March 13, 1989, Cooper Industries was made aware of circumstances at
Perry Unit 1 that led to the Division I EDG being declared inoperable. A
Crosby safety relief valve on one of the two EDG starting air receiving
tanks was inadvertently hit during maintenance activities. The force of the
impact caused the valve to open and blow down both air receiving tanks. The
safety relief valve did not reseat until approximately 30 psig below the EDG
automatic start lockout signal. On January 12, 1990, Cooper Industries
learned that a similar event had occurred at Comanche Peak. On January 17,
1990, Cooper Industries submitted a 10 CFR Part 21 report on the affected
safety relief valves (Crosby style JMBU and JRU safety relief valves).
Discussion of Safety Significance:
Although Crosby-style JMBU and JRU safety relief valves were designed to
meet the requirements of Section VIII of the ASME Boiler and Pressure Vessel
Code, they were not seismically qualified. In addition, the blowdown
characteristics of the valves were not consistent with the functional
requirements of the system in which they were installed. Cooper Industries
has recommended replacing these valves with seismically qualified valves
that have the proper blowdown reseat characteristics.
9003050043
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IN 90-18
March 9, 1990
Page 2 of 2
All licensees with Transamerica Delaval Inc. (TDI) diesel generators were
notified of this problem by Cooper Industries via the Part 21 notification.
However, Crosby safety relief valves (style JMBU, JRU, and possibly non-code
style JMB) may be installed on EDGs manufactured by other vendors.
Licensees may wish to verify that the relief valves installed in their EDG
air start systems have appropriate qualifications and characteristics.
This information notice requires no specific action or written response. If
you have any questions about the information in this notice, please contact
the technical contact listed below or the appropriate NRR project manager.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact: John Thompson, NRR
(301) 492-1175
Attachment: List of Recently Issued NRC Information Notices
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