Bulletin 84-03: Refueling Cavity Water Seal
SSINS No.: 6820
OMB No.: 3150-0011
Expiration Date: 04/30/85
IEB 84-03
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
August 24, 1984
IE BULLETIN NO. 84-03: REFUELING CAVITY WATER SEAL
Addressees:
All power reactor facilities holding an Operating License (OL) or
Construction Permit (CP) except Fort St. Vrain.
Purpose:
The purposes of this bulletin are to: (1) notify addressees of an incident
in which the refueling cavity water seal failed and rapidly drained the
refueling cavity, and (2) request certain actions to assure that fuel
uncovery during refueling remains an unlikely event.
Description of Circumstances:
On August 21, 1984, the Haddam Neck plant experienced a failure of the
refueling cavity water seal with the refueling cavity flooded in preparation
for refueling. The refueling cavity water level (23 feet) decreased to the
level of the reactor vessel flange within 20 minutes which flooded the
containment, with approximately 200,000 gallons of water. The seal assembly
consists of an annular plate with two pneumatic seals (Figure 1). The
assembly was recently redesigned by the licensee and had been used once
previously. The seal was manufactured by Presray, Inc. The seal assembly was
subject to a gross failure due to lack of an interference between the width
of the seal annulus and the width of the opening, which allowed the seal to
be significantly displaced. No fuel was being transferred at the time of
this seal failure. If, however, fuel had been in transfer at the time, it
could have been partially or completely uncovered with possible high
radiation levels, fuel cladding failure and release of radioactivity. In
addition, if the fuel transfer tube had been open, the spent fuel pool could
have drained to a level which would have uncovered the top of the fuel.
Action to be Taken by Plants Currently in Refueling:
1. Evaluate the potential for and consequences of a refueling cavity water
seal failure and provide a summary report of these actions by August 31,
1984.
8408240358
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IEB 84-03
August 24, 1984
Page 2 of 2
Action To Be Taken By Plants Prior To Beginning Refueling Or Within 90 Days
Of Receipt Of This Bulletin, Whichever Is Sooner:
2. Evaluate the potential for and consequences of a refueling cavity
water seal failure and provide a summary report of these actions.
Such evaluations should include consideration of: gross seal failure;
maximum leak rate due to failure of active components such as inflated
seals; makeup capacity; time to cladding damage without operator action;
potential effect on stored fuel and fuel in transfer; and emergency
operating procedures.
Written reports describing the above actions shall be submitted to the
appropriate Regional Administrator under oath or affirmation under
provisions of Section 182a, Atomic Energy Act of 1954, as amended. Also, the
original copy of the cover letter and a copy of the report shall be
transmitted to the U.S. Nuclear Regulatory Commission, Document Control
Desk, Washington, D.C. 20555 for reproduction and distribution.
This request for information was approved by the Office of Management and
Budget under a blanket clearance number 3150-0011 which expires April 30,
1985. Comments on burden and duplication may be directed to the Office of
Management and Budget, Reports Management, Room 3208, New Executive Office
Building, Washington, D.C. 20503.
If you have any questions regarding this matter, please contact the Regional
Administrator of the appropriate NRC Regional Office or the technical
contact listed below.
Richard C. DeYoung, Director
Office of Inspection and Enforcement
Technical Contact: H. Bailey, IE
(301) 492-7078
Attachments:
1. Figure 1
2. List of Recently Issued IE Bulletins
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