Information Notice No. 89-50: Inadequate Emergency Diesel Generator Fuel Supply
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
May 30, 1989
Information Notice No. 89-50: INADEQUATE EMERGENCY DIESEL GENERATOR FUEL
All holders of operating licenses or construction permits for nuclear power
This information notice is being provided to alert addressees to the potential
for existence of an inadequate emergency diesel generator (EDG) fuel supply.
It is expected that recipients will review the information for applicability
to their facilities and consider actions, as appropriate, to avoid similar
problems. However, suggestions contained in this information notice do not
constitute NRC requirements; therefore, no specific action or written response
Description of Circumstances:
During a review of the design basis for the EDGs at Palisades, it was dis-
covered that the fuel oil consumption calculations, performed in 1968, had
not been updated to reflect changes in equipment loading and operating times
in post-accident conditions. Subsequent calculations by the licensee
indicated that 23,000 gallons of diesel fuel would be required to ensure that
a seven day supply would be available to support EDG operation under the
current load requirements. This value exceeds the minimum 16,000 gallon limit
specified in the Technical Specifications (TS). The licensee's corrective
actions in-cluded prescribing a higher administrative limit of 23,000 gallons
of fuel and performing additional calculations to support a TS change request.
This is discussed further in licensee event report (LER) 50-255/89-005.
A discrepancy between the Final Safety Analysis Report (FSAR) and the TS basis
was identified at Robinson Unit 2. The TS basis specified that 25,000 gallons
of fuel oil be maintained for operation of one EDG carrying "minimum safety
features" load for seven days. The FSAR described the 25,000 gallons as suf-
ficient for one EDG carrying "full load" for seven days. Calculations
performed by the licensee indicate that 25,000 gallons is only marginally
sufficient for one EDG carrying "minimum safety features" load for seven days
since fuel consumption is highly dependent on selective load shedding. The
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May 30, 1989
Page 2 of 2
calculations also indicate that one EDG carrying "full load" for seven days
would require approximately 30,430 gallons. The licensee's corrective actions
included redefining the basis for the seven day fuel supply to the more con-
servative value (operation of the EDG at its rated capacity) and revising
the TS to reflect the increased minimum fuel inventory. This is discussed
further in NRC Inspection Report No. 50-261/87-06 and in LER 50-261/88-006.
The McGuire FSAR indicates that the underground storage tank for each EDG is
sized so that the corresponding EDG can carry the 4160 Volt Essential
Auxiliary Power Systems load for seven days. The TS require that each
underground storage tank contain a minimum volume of 28,000 gallons of fuel.
Recently, it was discovered that 28,000 gallons is not sufficient to ensure
seven days of EDG operation. The licensee has indicated that design
calculations show that appro-ximately 48,533 gallons of fuel are needed to
ensure seven days of operation at rated load. This is discussed further in
NRC Inspection Report No. 50-369/89-02.
Regulatory Guide 1.137, "Fuel Oil Systems for Standby Diesel Generators,"
contains guidance for calculation of EDG fuel oil storage requirements.
Two methods are provided: 1) calculations based on the assumption that
the EDG operates continuously for seven days at its rated capacity and
2) calculations based on the time-dependent loads of the EDG (which should
include the capacity to power the engineered safety features).
No specific action or written response is required by this information notice.
If you have any questions about this matter, please contact the technical
contact listed below or the Regional Administrator of the appropriate regional
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical Contact: Jack Ramsey, NRR
Attachment: List of Recently Issued NRC Information Notices
May 30, 1989
Page 1 of 1
LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
Information Date of
Notice No._____Subject_______________________Issuance_______Issued to________
89-49 Failure to Close Service 5/22/89 All holders of OLs
Water Cross-Connect or CPs for nuclear
Isolation Valves power reactors.
89-48 Design Deficiency in the 5/22/89 All holders of OLs
Turbine-Driven Auxiliary or CPs for nuclear
Feedwater Pump Cooling power reactors.
89-47 Potential Problems With 5/18/89 All holders of OLs
Worn or Distorted Hose or CPs for nuclear
Clamps on Self-Contained power reactors and
Breathing Apparatus fuel facilities.
89-46 Confidentiality of 5/11/89 All holders of
Exercise Scenarios licenses for fuel
having an approved
89-45 Metalclad, Low-Voltage 5/8/89 All holders of OLs
Power Circuit Breakers or CPs for nuclear
Refurbished with Sub- power reactors.
89-44 Hydrogen Storage on the 4/27/89 All holders of OLs
Roof of the Control Room or CPs for nuclear
88-82, Torus Shells with Corrosion 5/2/89 All holders of OLs
Supp. 1 and Degraded Coatings in or CPs for BWRs.
89-43 Permanent Deformation of 5/1/89 All holders of OLs
Torque Switch Helical or CPs for nuclear
Springs in Limitorque power reactors.
SMA-Type Motor Operators
88-97, Potentially Substandard 4/28/89 All holders of OLs
Supp. 1 Valve Replacement Parts or CPs for nuclear
OL = Operating License
CP = Construction Permit
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