Information Notice 1979-33, Improper Closure of Primary Containment Equipment Access Matches
| ML031180201 | |
| Person / Time | |
|---|---|
| Site: | 05000000 |
| Issue date: | 12/21/1979 |
| From: | NRC/OI |
| To: | |
| References | |
| IN-79-033, NUDOCS 7910250520 | |
| Download: ML031180201 (2) | |
UNITED STATES
SSINS NO.:
6870
NUCLEAR REGULATORY COMMISSION
Accession No.:
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
791025 52 c
December 21, 1979
IE 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 contain- ment 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 pro- cedures for access hatch installation at all facilities. If installation pro- cedures 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.
IE Information Notice No. 79-33
December 21, 1979
Enclosure
RECENTLY ISSUED
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Date
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79-31
79-30
Separation of Electrical
Use of Incorrect Amplified
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Reporting of Defects and
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Loss of NonSafety-Related
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All holders of power reactor
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After A Main Steam Line
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All power reactor facilities
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power reactors with an
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10/1/79
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All power reactor facilities
with a CP