Safety Concerns Associated with Pipe Breaks in the BWR Scram System (Generic Letter 81-35)
UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D.C. 20555
August 31, 1981
TO ALL BWR APPLICANTS FOR CP's, HOLDERS OF CP's, AND APPLICANTS FOR OL's
Gentlemen:
SUBJECT: SAFETY CONCERNS ASSOCIATED WITH PIPE BREAKS IN THE BWR SCRAM
SYSTEM (GENERIC LETTER 81-35)
In April 1981 the NRC staff sent a letter to each BWR license applicant
requesting certain information on this subject. We indicated that this item
must be resolved prior to issuance of an operating license. Subsequently, on
July 7, 1981 the NRC staff sent a letter to all BWR licensees informing them
that the generic review of this issue had been completed. We indicated that
a NUREG report describing the results of this letter would be issued.
This letter forwards NUREG-0803, "Generic Safety Evaluation Report Regarding
Integrity of BWR Scram System Piping," dated August 1981. Section 5 of
NUREG-0803 presents the staff's generic conclusions on this issue. Briefly,
the staff has concluded that the SDV piping system design is acceptable,
provided certain conditions are satisfied on a plant specific basis. The
staff further concluded that the safety concerns associated with a
postulated failure of the SDV piping system do not represent a dominant
contribution to the risk of core melt, provided certain assumptions used in
the risk assessment are validated on a plant specific basis.
NUREG-0803 provides the staff's guidance and schedule for implementation. As
provided in our April 1981 letter, cited above, plant specific responses
should be provided for all plants with Mark I and Mark II containments to
support issuance of an operating license. Plant specific responses
conforming to the guidance contained in NUREG-0803 will satisfy the
information requested in our April 1981 letter. This letter is being
provided to applicants with Mark III containments for information purposes,
since the staff has concluded that this is not a safety issue for the Mark
III containment design.
Sincerely,
Darrell G. Eisenhut, Director
Division of LIcensing
Office of Nuclear Reactor Regulation
Enclosure:
As stated
cc: Service List
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