Information Notice No. 89-50: Inadequate Emergency Diesel Generator Fuel Supply

                                  UNITED STATES
                          NUCLEAR REGULATORY COMMISSION
                             WASHINGTON, D.C.  20555

                                  May 30, 1989



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 
is required.

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
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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
                    (301) 492-1167

Attachment:  List of Recently Issued NRC Information Notices
..                                                            Attachment 
                                                            IN 89-50
                                                            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.
               Water System

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 
                                                            cycle facilities 
                                                            and byproduct 
                                                            material licensees 
                                                            having an approved 
                                                            emergency response 

89-45          Metalclad, Low-Voltage        5/8/89         All holders of OLs
               Power Circuit Breakers                       or CPs for nuclear
               Refurbished with Sub-                        power reactors.
               standard Parts

89-44          Hydrogen Storage on the       4/27/89        All holders of OLs
               Roof of the Control Room                     or CPs for nuclear
                                                            power reactors.

88-82,         Torus Shells with Corrosion   5/2/89         All holders of OLs
Supp. 1        and Degraded Coatings in                     or CPs for BWRs.
               BWR Containments

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
                                                            power reactors.
OL = Operating License
CP = Construction Permit 

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