ML19269D284
| ML19269D284 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 09/28/1979 |
| From: | Streeter J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML19269D283 | List: |
| References | |
| NUDOCS 7903270416 | |
| Download: ML19269D284 (2) | |
Text
W UNITED STATES 1.-
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.s MW Docket No. 50-346 wwa y
MEMORANDLH FOR:
E. L. Jordan, Assistant Director f or Technical Programs,
Office of Inspection and Enforcement G
G. Fiorelli, Chief, Reactor Operations and Nuclear U dj THRU:
Q Support Branch SEU FROM:
J. F. Streeter, Chief, Nuclear Support Section 1 DAVIS-BESSE 1 - OPERATOR ACTION TO PREVENT OVERLOADING 3b
SUBJECT:
D EMERGENCY DIESEL GENERATORS DURING A LOCA FOLLOWING A
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LOSS OF OFFSITE POWER (AITS F30408H2) (AITS F30426H2)
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REFERENCE:
MDiORANDUM FROM J.F. STREETER TO R. WOODRUFF DATED AUGUST 7,1978 The referenced tremorandum described an emergency diesel generator overload A
problem which was based on verbal information supplied by the licensee.
followup inspection of this matter was conducted on August 29-31, 1978.
It was determined that the potential problem did not exist with overloading s
g and stalling of the emergency diesel generators in the event a LOCA occurred
$g af ter offsite power had been lost and af ter a reactor coolant system trakeup
.Mty IE W pump had been placed on the EDG bus.
Consequently, the licensee's interim manual action controls and proposed modification to provide an automatic stripping feature are deemed by Region III to be optional on the part of
- N the licensee and will not be pursued by this office.
Region III has surveyed nine other plants and determined that similar prob-(
lems do not exist at those plants.
Therefore, there is no need for a
- 1 Bulletin or Circular and Region III no longer recommends that other Regions be informed of this potential problem. These recommendations were discus-sed in telephone conversations between Vince Thomas of your staff and I
obviate immediare, operator action to avoid overloading the EDG's in the myself imm-diately after the followup inspection.
The referenced memorandum also stated that there did not appear to be any regulatory bases for requiring an electrical system design which would a LOCA occGrred subnequent to a loss of offsite power. After further event review we have concluded that regulatory bases do exist. Specifically, N
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i September 28, 1975 F
L. Jordan General Design Criteria 17 and 20 and Regulatory Guide 1.9 taken together indicate that manual action should not be immediscely necessary to assure completion of auto =stic protective actions.
During our followup review of this matter, we discussed with NRR the ceaning for demonstrating the of the following 18-montn STS surveillance requirement operability of the EDG's:
Si=ulating a loss of offsite power in conjunction with a safety signal, and verifying de-energi:ation injection actuation test of the essential busses and load shedding from the essential busses.
Literally taken, this requirement includes all possible sequences whereby a could experience a LOCA in ecmbination with a loss of off site power.
plant The possible sequences are (1) a simultaneous LOCA and loss of offsite power, loss of offsite power (2) a LOCA followed by loss of of f site power, and (3) followed by a LOCA. However, NP.R has indicated that the above STS was caly intended to cover the simultaneous case. From our knowledge, most if not We do not all plants conduct their tests using simultaneous signals.
believe the tests should be conducted in that manner because the simultaneo cover at all plants the most demanding loading combinations case does not the EDG's would see. For example, at Davis-Besse 1 if a loss of offsite power has occurred end the makeup pumps have been placed on the EDG's, a subsequent LOCA would result in ECCS load being sequenced on top of the 18-month EDG tests should be conducted under the makeup pump loads. The most demanding leading ce=binations that could exist for any sequence of occurrence of a LOCA and loss of offsite power.
We recommend that NRR be requested ~ to review its intended STS testing require-ments and determine the need f or more conservative EDG testing requirements This reco==endation supersedes the recommendation in as described above.
the referenced memorandum.
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<1 J. F. Streeter, Chief
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Nuclear Support Section I
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R. C. Raop
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G. Fiorelli
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T. N. Tambling
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- w =v J. D. Smith
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0 N OSO /[I/M T IE Files Central Files CONTACT:
J. D. Smith 37-387-922S
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