Information Notice 1979-33, Improper Closure of Primary Containment Equipment Access Matches

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 Enclosure

December 21, 1979

RECENTLY ISSUED

IE INFORMATION NOTICES

Information Subject Date Issued To

Notice No. Issued

79-32 Separation of Electrical 12/21/79 All power reactor facilities

Cables for HPCI and ADS holding OLs and CPs

79-31 Use of Incorrect Amplified 12/13/79 All holders of power reactor

Response Spectra (ARS) OLs and CPs

79-30 Reporting of Defects and 12/6/79 All power reactor facilities

Noncompliance, 10 CFR Part 21. holding OLs and CPs and

vendors inspected by LCVIP

79-29 Loss of NonSafety-Related 11/16/79 All power reactor facilities

Reactor Coolant System holding OLs or CPs

Instrumentation During

Operation

79-28 Overloading of Structural 11/16/79 All power reactor facilities

Elerents Due to Pipe Support with an OL or CP

Loads

79-27 Steam Generator Tube 11/16/79 All power reactor facilities

Ruptures At Two PWR holding OLs and CPs

Facilities79-12A Attempted Damage To New 11/9/79 All Fuel Facilities, Fuel Assemblies research reactors, and

power reactors with an

OL or CP

79-26 Breach of Containment 11/5/79 All power reactor facilities

Integrity holding OLs and CPs

79-25 Reactor Trips At Turkey 10/1/79 All power facilities with

Point Units 3 And 4 an OL or a CP

79-24 Overpressurization Of 10/1/79 All power reactor facilities

Containment Of A PWR Plant with a CP

After A Main Steam Line

Break