ML19225C639
| ML19225C639 | |
| Person / Time | |
|---|---|
| Issue date: | 07/02/1979 |
| From: | Eisenhut D, Eisenhut E Office of Nuclear Reactor Regulation |
| To: | Mattson R Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-CR-0660, RTR-NUREG-CR-660 NUDOCS 7908010589 | |
| Download: ML19225C639 (4) | |
Text
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NUCLEAR REGULATOAY COMMISSION E
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Jul 2 1979
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MEMORANDUM T0:
R. J. Mattson, Director, Divis, ion of Systems Safety FROM:
D. Eisenhut, Acting Director, Division of Operating Reactors OPERATING EXPERIENCE MEMORANDUM NO.15 - RELIABILITY OF THE EMERGENCY ONSITE DIESEL GENERATORS
Reference:
NUREG/CR 0660 Enhancement of Onsite Emergency Diesel Generator Reliability 1.
Problem Diesel generator operating experience has proven to be less reliable than that anticipated. To assist NRC/ DOR in identifying the problems and arriving at the proper corrective action a contract was let to the University of Dayton Research Institute (U of D) to perfonn a comprehensive review.
This review included operating experience, maintenance, and a comparative evaluation of their findings with respect to the DG manufacturers recommendations. Their final report, NUREG/CR 0660 is being (istributed to all operating facilities, construction permit holders and applicants for construction pennits. The report identified essentially thirteen problem areas and associated recommend-ations which, with one exception, were generic. The exception only applied to plants having a specific type diesel engine. The recomendations have been grouped into three categories, depending on their relative importance.
DOR is proposing that a review of all operating plants be initiated by issuing an I&E Bulletin requiring all plants, that were in an operational status as of June 1,1979, respond to each of the report's recomendations.
The respondents are to describe their facility with respect to the recomend-ations, to comit to the implementation of the recomendation or provide justification why the present system is adequate.
For those plants that have not reached an operational status by June 1,1979, it is proposed that DSS cover these concerns in their normal review process.
2.
Presumed Cause The thirteen problem areas that degrade the reliability of the diesel generators are shown below.
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JUL 2 1979
' I.
Most Significant Problems a) Moisture in the Air Starting System b) Dust and Dirt in Diesel Generator Compartments c) Turbocharger Gear Drive Changeover d) Personnel Training II.
Significant Problems a) Length of Pre-lube Time b) Testing, Test Loading & Preventative Maintenance c)
Improve the Identification of Root Causes of Failures III. Additional Problems a)
D.G. Room Ventilation and Combustion Air Intake Systems b) Fuel Storage and Handling c) High Temperature Insulation for Generator Overload Conditions d) Engine Cooling Water Temperature Control e) Concrete Dust Control f) Vibration of Instruments and Controls In category I, the cause for items (a), (b) and (d) are self evident.
Item (c) relates to the adequacy of the gear train of the Electro-Motive Division of General Motors (EMD-GM) diesel engines.
EMD-GM iMicates that it has been redesigned and kits, consisting of replacement,_ets, are available to accomplish the changeover.
In category II, item (a) relates to engine problems that are likely to be encountered if insufficient or excessive engine lubrication exists.
(EMD-GM has already notified all owners of their engines of the potential for insuffi-cient lubrication, interim administrative actions to mitigate the problem and their comitment to have the engine modifications available in six months.) The causes of items (b) and (c) are self evident.
In category III, item (a) relates to the detrimental effects of dust, dirt, grit, hot air and engine exhaust being drawn into the diesel engine compart-ment.
Item (b) deals with the accumulation of moisture in the fuel oil system and an adequate net positive suction head at the fuel oil pumps.
Item (c) recomends that the generator insulation essentially be derated in order to avoid unanticipated overloads from causing a generator fire (this recomendation would be primarily directed at new facilities).
Item (d) relates to a recomended system for reliably controlling the temperature of the cooling water.
Item (e) essentially is the same as category I (b) and part of category III (a) in that it minimizes concrete dust and grit in the 421 089
JUL 2 1979 diesel engine compartment.
Item (f) is concerned with the damaging effects of engine vibration on instruments, control and monitoring elements that are experienced on skid mounted units.
(This recomendatior. is primarily directed at new plants.),
3.
Safety Significance The onsite emergency diesel generators, as a class of engineered safety system, is essential in the event of a loss of off-site power. Operating experience has shown that the units have not attained the desired reliability goal of 0.99.
4.
Repair The repair on the operating plants will consist of reviewing and evaluating the existing systems in relation to the above described U of D recomendations.
The implementation of each recomendation will balance the relative improve-ment in reliability against any adverse effect its implementation will have on the plant.
Due to variations in plant designs, the degree of implementation will vary among plants.
5.
D0R Action D0R is proposing that an I&E Bulletin be issued which will require all plants, in an operational status as of June 1,1979, to respond to the recommendations contained in NUREG/CP 0660.
I&E will receive and evaluate the responses.
6.
Recomendations DOR recomends that DSS review and evaluate NUREG/CR 0660 from the standpoint of its applicability to all plants that have not reached an operational status as of June 1,1979. Where it is found that the recommendations are applicable, DSS could implement the appropriate recommendations in the nomal plant review process.
Further, it is recomended that PSB/ DSS revise the existing Standard Review Plans where appropriate.
In addition, in those cases where it is determined that new, or revisions to existing, Regulatory Guides, IEEE or other industry standards are warranted, PSB/ DSS should have prime responsibility for seeing that it is accomplished.
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. tisen t,' Actf 1 rector Division of Operating Reactors Office of Nuclear Reactor Regulation 421 090
JUL 2 B79.
Principal D0R Personnel Reviewer:
F. Clemenson, 00R A. Ungaro, DSS Project Manager:
F. Clemenson (B-56) cc:
H. R. Denton E. G. Case D. Vassallo D. Nuller F. Schroeder DSS AD's D0R AD's DOR BC's DOR SL's J. Sniezek L. Nichols F. Clemenson V. Moore F. Rose A. Ungaro S. Hanauer H. Ornstein E. Jordan 421 091