United States Nuclear Regulatory Commission - Protecting People and the Environment
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IE Circular 77-15, Degradation of Fuel Oil Flow to the Emergency Diesel Generator


CR77015 

                            November 28, 1977 

MEMORANDUM FOR:     B. H. Grier, Director, Region I 
                    J. P. O'Reilly, Director, Region II 
                    J. G. Keppler, Director, Region III 
                    E. M. Howard, Director, Region IV 
                    R. H. Engelken, Director, Region V 

FROM:               H. D. Thornburg, Director, Division of Reactor    
                    Operations Inspection, Office of Inspection and  
                    Enforcement 

SUBJECT: IE CIRCULAR 77-15, DEGRADATION OF FUEL OIL FLOW TO THE EMERGENCY DIESEL GENERATOR 

The subject circular is transmitted for issuance by close of business within
three days after date of this letter. The Circular should be issued to all 
holders of Reactor Operating Licenses or Construction Permits. Also enclosed
is a draft copy of the transmittal letter. 


                                        Harold D. Thornburg, Director  
                                        Division of Reactor Operations 
                                          Inspection 
                                        Office of Inspection and Enforcement 

Enclosures: 
1. Draft Transmittal Letter 
2. IE Circular 77-15 

CONTACT:  C. J. DeBevec 
          49-28180 
.

IE Circular No. 77--15                                             (Date) 

(Transmittal letter for IE Circular 77-15 to each holder of an NRC Operating
License or Construction Permit.) 

Addressee: 

The enclosed IE Circular No. 77-15 is forwarded to you for information. No 
written response is required. Should you have any questions related to your 
understanding of this matter, please contact this office. 

                                        Sincerely, 


                                        Signature 
                                        (Regional Director) 

Enclosures: 
1. IE Circular No. 77-15 
2. List of IE Circulars 
     Issued in 1977 
.

                             UNITED STATES 
                      NUCLEAR REGULATORY COMMISSION 
                   OFFICE OF INSPECTION AND ENFORCEMENT 
                          WASHINGTON D.C. 20555 

                            November 23, 1977  

                                                     IE Circular No. 77-15 

DEGRADATION OF FUEL OIL FLOW TO THE EMERGENCY DIESEL GENERATOR 

During surveillance testing on July 14, 1977, personnel at the Cooper 
Nuclear Station noted a degradation of fuel oil flow to the day tank for the
emergency diesel generator. Although the fuel oil transfer pump capacity is 
13.8 gpm for each of the two redundant pumps, flow to the day tank for 
number one diesel generator was only 3 gpm. At full load, engine consumption 
is 4.5 gpm. 

Investigation of this occurrence revealed a clogged strainer in a float 
operated shutoff valve on the day tank inlet. This valve operates as a 
backup to level switches which start and stop the fuel oil transfer pumps to
maintain normal day tank level. The strainer is an integral part of the 
float valve assembly and is not shown on the as-built system drawings. This 
valve was manufactured by McDonnell-Millen Company. Station personnel were 
thus unaware of the presence of this strainer and did not schedule it for 
routine strainer cleaning under the preventive maintenance program. Normal 
testing of the system under the Technical Specification surveillance 
requirements does not verify system flow rates. 

This occurrence represents an example where the as-built system 
configuration was not accurately indicated on the system drawings, and that 
adequate system description was apparently not available to Station 
personnel. 

All holders of construction permits or operating licenses should be aware of
the potential for variance between as-built configurations and system 
drawings. This is especially true for support systems to the engineered 
safeguards features where all required system conditions such as pressure 
and flows may not receive routine testing under the surveillance testing 
program. It is recommended that the following be considered in your review 
of this matter: 

1.   A field verification of the drawing against the as-built system 
     configuration should be made for the entire diesel generator fuel oil 
     delivery system from the storage tanks to the engines. Appropriate 
     changes should be made to the drawings and preventive maintenance 
     program to account for any components or configurations not previously 
     covered. 

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IE Circular No. 77-15                            November 23, 1977 

2.   Consideration should be given to revising surveillance test procedures 
     to include a flow test on the fuel oil system to ensure the system 
     continues to meet design specifications. 

In addition, the following information relating to the maintenance of fuel 
oil cleanliness should be considered in your review: 

1.   During long-time storage, degradation of fuel oil is a common 
     occurrence. The rate of degradation is not easily predicted since it is
     a function of the source of the crude oil, the process utilized in 
     making the fuel (e.g., straight distillation or the method of catalytic
     cracking), and the conditions under which the fuel oil is stored. 

2.   It is known that certain detrimental processes are accelerated in fuel 
     oils when they are in contact with certain metals. The presence of 
     zinc, such as from galvanizing, has a tendency to form soluble soaps in 
     the fuel oil which are deposited on the diesel engine's injection 
     nozzles. A buildup of this deposit will eventually degrade the engine's 
     performance. The presence of copper promotes the formation of gums 
     which degrade the stored fuel oil and tends to clog filters. 
     
3.   The presence of water in the fuel oil promotes the growth of fungi or 
     slime that also degrades the fuel and has the potential for clogging 
     filters. 

No written response to this Circular is required. If you require additional 
information regarding this matter, contact the Director of the appropriate 
NRC Regional Office. 

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