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HomeNRC LibraryDocument CollectionsGeneric CommunicationsInformation Notices1979

# 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.
```

*Page Last Reviewed/Updated Friday, May 22, 2015*

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