Information Notice No. 84-42: Equipment Availability for Conditions During Outages Not Covered by Technical Specifications
SSINS No. 6835
IN 84-42
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, DC 20555
June 5, 1984
Information Notice No. 84-42: EQUIPMENT AVAILABILITY FOR CONDITIONS
DURING OUTAGES NOT COVERED BY TECHNICAL
SPECIFICATIONS
Addressees:
All holders of a nuclear power plant operating license (OL) or construction
permit (CP).
Purpose:
This information notice is provided to alert licensees to the importance of
controlling equipment availability for conditions during outages not covered
by Technical Specifications. It is expected that recipients will review the
information for applicability to their facilities and consider actions, if
appropriate, to preclude similar problems occurring at their facilities.
However, suggestions contained in this information notice do not constitute
NRC requirements and, therefore, no specific action or written response is
required.
Description of Circumstances:
On January 8, 1984, the Palisades Nuclear Plant experienced a complete loss
of offsite and onsite ac power. The event was precipitated by the need to
isolate a faulty switchyard breaker. To isolate the breaker, it was
necessary to interrupt the offsite power supply to the plant. At the time of
the event, Palisades was in a refueling outage with all fuel removed from
the reactor and the no. 2 diesel generator (DG) inoperable. The service
water pump powered from the no. 1 (operable) DG also was inoperable as a
result of maintenance.
When the shift supervisor interrupted the offsite power supply to the plant,
the operators did not realize cooling water to the operable DG was not
available. The control room alarm indication, which should have warned the
operators, was apparently masked by the large number of simultaneous alarms
received when the offsite power was interrupted. Approximately 50 minutes
later the DG overheated and was manually tripped. Once the DG was tripped,
all station power was lost, with the exception of the station batteries and
their associated dc and preferred ac buses. The loss of ac power caused a
loss of plant communications, fire protection, security, and habitability
systems as well as the fuel pool cooling system. (Compensatory measures were
promptly taken upon loss of the normal security systems.) The loss of
communications is considered the most serious consequence of this event.
This loss of communications will be further addressed in a separate
information
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IN 84-42
June 5, 1984
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notice (IN). The restoration of ac power was delayed as a result of an inop-
erable main transformer (out for maintenance) and a malfunction of one of
the startup supply breakers.
While operating procedures required two operable diesel generators,before
removing offsite power, operating procedures did not specifically delineate
equipment availability requirements for this defueled condition. The shift
supervisor violated the procedure and proceeded with the evolution after
evaluating fuel cooling. The fuel pool was known to heat up very slowly and
to require days without active cooling before the high temperature alarm
would be reached. The shift supervisor, however, failed to fully recognize
the importance of the other support systems (e.g., communication, fire pro-
tection) to the *overall safety of the plant. The procedural requirements
were reviewed as part of the evaluation of fuel cooling and it was
determined their intent was to minimize risk to fuel integrity when the fuel
was in the reactor vessel.
Following the loss of onsite and offsite ac power, the Emergency Procedures
were not implemented in a timely manner because the importance of the
various support systems had not been recognized.
The licensee initiated many corrective actions as a result of this event
(see Palisades Licensee Event Report (LER) 84-001). Some of the more
important corrective actions by the licensee include:
1. A review of the management control of equipment for plant conditions
not covered by the requirements of the Technical Specifications. The
review will specifically address electrical system requirements during
cold shutdown to ensure sufficient equipment remains available to
maintain the plant in a safe condition and to meet the commitments of
the Site Emergency, Security, and Fire Protection Plans.
2. Establishing minimum equipment availability for specific conditions not
covered by the Technical Specifications.
3. Provide classroom training for all operators on the use and intent of
the Site Emergency Plan.
4. Integrate the use of the Site Emergency Plan into simulator training.
5. Discuss the need for strict adherence to operating procedures with all
operations personnel.
NRC has previously identified concerns with operability of required
equipment in IE IN 83-56, "Operability of Required Auxiliary Equipment," and
IN 80-20, "Loss of Decay Heat Removal Capability at Davis-Besse Unit 1 While
in a Refueling Mode." If you have any questions regarding this matter,
please
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IN 84-42
June 5, 1984
Page 3 of 3
contact the Regional Administrator of the appropriate NRC Regional Office or
this office.
Edward L. Jordan, Director
Division of Emergency Preparedness
and Engineering Response
Office of Inspection and Enforcement
Technical Contact: H. Bailey, IE
(301) 492-7078
Attachment:
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