Information Notice No. 79-26, Breach of Containment Integrity
IN79026
UNITED STATES
NUCLEAR REGULATORY COMMISSION
WASHINGTON, D. C. 20555
November 1, 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, IE
SUBJECT: Information Notice No. 79-26, BREACH OF CONTAINMENT
INTEGRITY
The subject document is transmitted for issuance on November 5, 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. IE Information Notice
No. 79-26
2. Draft Transmittal Letter
CONTACT: P. F. McKee, IE
49-28019
.
(Transmittal letter for Information Notice No. 79-26 to each holder of an
NRC Operating License and Construction Permit.)
Information Notice No. 79-26
Addressee:
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. If further NRC evaluations so
indicate, an IE Circular, Bulletin, or NRR Generic Letter will be issued to
recommend or request specific licensee actions. If you have questions
regarding the matter, please contact the Director of the appropriate NRC
Regional Office.
Signature
(Regional Director)
Enclosures:
1. Information Notice No.
No. 79-26
2. List of IE Information
Notices Issued in the
Last Six Months
.
SSINS: 6870
Accession No:
7908220133
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D. C. 20555
November 5, 1979
Information Notice No. 79-26
BREACH OF CONTAINMENT INTEGRITY
Description of Circumstances:
On September 14, 1979, the Consumers Power Company (CPC) notified the NRC of
discovery at the Palisades Nuclear Generating Plant of a valve misalignment
that had resulted in containment integrity being breached for an
indeterminate length of time.
While preparing to perform a Type "C" leak test between two manual valves in
a 3" bypass line around the main 48" containment purge valve, plant
personnel discovered that both of these manual isolation valves were locked
in the open position. These valves should have been locked closed.
Investigation by the licensee indicated that the valves may have been
improperly positioned since April, 1978, when an efficiency test of the
bypass line filters was performed. The plant has operated at power for the
major portion of that time period.
The valve misalignment had no actual impact on the public health. However,
in the event of a design basis accident wherein fuel damage and release of
primary coolant inside the containment are postulated, the open valves would
provide a significant path for a radioactive release from the containment.
The initial design purpose for the bypass system was to provide a long term
hydrogen control capability for the containment atmosphere following a
design basis accident.1 It was intended that after approximately 30 days
following an accident, when containment pressure and activity levels dropped
sufficiently to permit venting, this system would be manually valved to vent
the containment atmosphere, through high efficiency and charcoal filters, to
the exhaust stack. Thus the components in the bypass line beyond the two
manual isolation valves were not designed for the severe service they would
be exposed to with the valves open during the initial pressure surge of the
design basis accident, and significant uncontrolled release would result.
High radiation in the vicinity of the bypass line would also make immediate
closing of the manual isolation valves, even if identified as the source of
leakage, an extremely hazardous operation.
The principal cause for this event was inadequacy of the procedures
addressing proper use and positioning of these valves. The master
containment integrity valve line-up checklist, which is performed prior to
each startup from cold
________________________________
1/ Current NRC requirements call for the use of hydrogen recombiners to
control hydrogen buildup. Palisades has recombiners installed.
.
Information Notice No. 79-26 November 5, 1979
Page 2 of 2
shutdown, did not include these valves. The filter efficiency test for the
3" bypass line did not adequately specify the final position of these
valves, and this is the probable cause for the valves being left incorrectly
positioned. The valve misalignment represents a case where human factors in
the form of inadequate procedures resulted in a loss of safety system
function.
CPC has updated the above mentioned procedures to assure that proper
positioning of these valves is addressed. Concurrently, CPC is reviewing
other paths from containment to assure that procedures and checklists are
complete. CPC has also hired a qualified consultant to perform an
independent review for the same purpose.
This Information Notice is provided as an early notification of a
significant occurrence. It is expected that recipients will review the
information for possible applicability to their facilities. No written
response is required. If you desire additional information regarding this
matter, contact the Director of the appropriate NRC Regional Office.
.
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