Information Notice No.: 79-33- Improper Closure of Primary Containment Access Hatches
IN79033
December 21, 1979
MEMORANDUM FOR: B. H. Grier, Director, Region I
J. P. O'Reilly, Director, Region II
J. G. Keppler, Director, Region III
K. V. Seyfrit, Director, Region IV
R. H. Engelken, Director, Region V
FROM: Norman C. Moseley, Director, Division of Reactor
Operations Inspection, Office of Inspection and
Enforcement
SUBJECT: Information Notice No. NO.: 79-33- IMPROPER CLOSURE OF
PRIMARY CONTAINMENT ACCESS HATCHES
The subject document is transmitted for issuance on December 21, 1979. The
Information Notice should be issued to all power reactor facilities holding
operating licenses and construction permits.
Also enclosed is a draft copy of the transmittal letter.
Norman C. Moseley, Director
Division of Reactor Operations
Inspection
Office of Inspection and Enforcement
Enclosures:
1. Draft Transmittal Letter
2. IE Information Notice
No. 79-33
CONTACT: W. R. Mills, IE
49-28180
.
(Transmittal letter for Information Notice No. 79-33 to each holder of an
NRC Operating License and Construction Permit.)
Information Notice No. 79-33
This Information Notice is provided as an early notification of a possibly
significant matter. It is expected that recipients will review the
Information for possible applicability to their facilities. No specific
action or response is requested at this time. However, we anticipate that
further NRC evaluations will result in issuance of an IE Circular or
Bulletin in the near future which will recommend or request specific
applicant or licensee actions. If you have questions regarding the matter,
please contact the Director of the appropriate NRC Regional Office.
Sincerely,
(Signature)
(Regional Director)
Enclosure:
1. IE Information Notice
No. 79-33
2. List of Recently Issued
Information Notices
.
UNITED STATES SSINS No.: 6870
NUCLEAR REGULATORY COMMISSION Accession No:
OFFICE OF INSPECTION AND ENFORCEMENT 7910250520
WASHINGTON, D.C. 20555
December 21, 1979
Information Notice No. 79-33
IMPROPER CLOSURE OF PRIMARY CONTAINMENT EQUIPMENT ACCESS HATCHES
Description of Circumstances:
On December 8, 1979 difficulty was experienced in establishing the required
nitrogen pressure in primary containment during power range startup testing
of the Browns Ferry Nuclear Plant, Unit 3, following a refueling outage. On
December 9, 1979, the licensee found three loose bolts on an equipment hatch
to be the cause of leakage from the primary containment. The leakage was
calculated to have been ten times the allowable containment leakage rate.
This hatch had previously passed a local leak rate test (LLRT) and an
integrated leak rate test of the containment in November 1979. The reactor
had returned to operation on December 6, 1979 from the refueling outage and
had operated at power levels less than 25 percent since December 6, 1979.
A subsequent inspection by the licensee of both primary containment
equipment access hatches for Unit 2 was performed. TVA reported on December
20, 1979, to the NRC that they had found six of twelve closing dogs on one
hatch improperly aligned and one closing bolt not torqued. A LLRT, performed
with the hatch in this condition, showed a leakage rate higher than normal
but within Technical Specification limits. The second hatch on this unit was
found to have eight of twelve closing dogs improperly aligned.
The licensee is in the process of inspecting the closure of both primary
containment equipment access hatches on Unit 1 and is reinspecting these
hatches on Unit 3.
It is anticipated that further NRC evaluation will result in issuance of an
IE Circular or Bulletin in the near future which will recommend or request
specific applicant or licensee actions.
This information is provided to inform licensees of a possibly significant
matter. The improper closure of the primary containment access hatches
resulted from a lack of procedures for torque values, sequence of torque,
and alignment of the closing dogs. We expect that recipients will review the
adequacy of their procedures for access hatch installation at all
facilities. If installation procedures do not exist or are inadequate,
inspection and local leak rate testing can be used to confirm containment
penetration integrity. If you have any questions regarding this matter,
please contact the Director of the appropriate NRC Regional Office.
No written response to this Information Notice is required.
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