ML20245A300
| ML20245A300 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 06/12/1989 |
| From: | Shelton D TOLEDO EDISON CO. |
| To: | |
| Shared Package | |
| ML20245A299 | List: |
| References | |
| NUDOCS 8906210196 | |
| Download: ML20245A300 (7) | |
Text
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Dock:t Numb:r 50-346
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'Lic nsa Nunb:r NPF-3 Serial Number 1670 1
Enclosure i
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APPLICA1' ION FOR AMENDHENT TO
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FACILITY OPEPATING LICENSE NUMBER NPF-3 DAVIS-BESSE NUCLEAR POWER STATION UNIT NUMBER-1 1
I Attached are requested changes a, the Davis-Besse Nuclear Power Station, Unit No. 1 Facility Operating License Number NPF-3.
Also included are the Technical Description and Significant Hazards Consideration.
The proposed changes (submitted under cover letter Serial Number 1670) concern:
Section 3/4.8.1.1, A. C. Sources - Operating, Surveillance Requirement 4.8.1.1.2 and Section 3/4.8.1.2, Electrical Power Systems - Shutdown, l
i Surveillance Requirement 4.8.1.2.
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i By:
D.~C.
Shelton, Vice PreslHsnt, Nuclear Sworn and subscribed before me this 12th day of June, 1989.
LGLLI k i /L L
I Notary Public, State of Ohio LAURlE A. HINKLE Notary Public. State of Ohio cy Commission Expires May 15,1991 l
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,SDOCK 05000346 P
j Docket Number 50-346 4 Li' cense Number NPF-3 Serial Number 1670
'j Enclosure Page 2-The following information is provided to support issuance of the requested changes to the Davis-Besse Nuclear Power Station, Unit No. 1 Operating License 1
Number NPF-3, Appendix A, Technical Specification, Section 3/4.8.1.1 and.
1 3/4.8.1.2.
A.
Time Required to Implement: This change is to.be implemented within 45-days after the Nuclear Regulatory Commission issuance of the License Amendment.
B.
Reason for Change (License Amendment Request-Number 88-0019):-
Surveillance' Requirements 4.8.1.1.2.d.1 andl4.8.1.2 require that at.least once per 18 months each emergency diesel generator be inspected by procedures prepared in conjunction vith its manufacturer's recommendations. This inspection cannot be performed within the bounds of
-the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> action statement'and,-therefore, requires an outage of significant duration. The 18 month frequency was provided to allow performance of the inspection during refueling outages.
Experience has shown that the time period between outages.is routinely greater than 18 months. The change of the frequency of this inspection to once per 30' months vould prevent an unnecessary shutdown to perform this-inspecticn.
C.
Technical
Description:
.See attached Technical Description (Attachment 1).
D.
Significant Hazards Consideration:
See attached Significant Hazards l
Consideration (Attachment 2).
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.' Docket' Number 50-346'
- License Number NPF-3 Serial Number 1670 Page 1 TECHNICAL DESCRIPTION-Description of Proposed Technical Specification Change The purpose of this Technical Description is to provide technical justification for a permanent extension of the 18 month interval of Surveillance Requirement (S.R.) 4.8.1.1.2.d.1 described in Appendix A, Technical Specifications, of the Davis-Besse Nuclear Power Station (DBNPS).
Operating License. The DBNPS Technical Specifications (T.S.), Section 3/4.8.1 Electrical Power Systems, A.C. Sources, Surveillance Requirements 4.8.1.1.2 and 4.8.1.2 require that the Emergency Diesel Generators (EDGs) be demonstrated operable by performing certain tests once.per 18 months. S.R.
4.8.1.1.2.d.1 requires that each emergency diesel generator be subjected t o an-inspection in accordance with procedures prepared in conjunction with the manufacturer's (Morrison-Knudsen Company, Inc.) recommendations for this class of standby service. This proposed amendment will' extend the surveillance period for performance of this inspection of the EDGs from "at least once per 18 months during shutdown" to "at least once-per.30 months". This Technical Specification change vill also delete the applicabili,ty of T.S. 4.0.2 from S.R. 4.8.1.1.2.d.1.
Surveillance Requirement 4.8.1.2 defines the operability requirements for the EDGs in modes 5 and 6, and also references S.R. 4.8.1.1.2 of the Technical Specifications.
A related license amendment request (Serial Number 1430) was submitted to the NRC on October 9, 1987. This license amendment requested a one-time extension for performance of inspection and operational testing for S.R. 4.8.1.1.2.d.1 and S.R. 4.8.1.1.2.d.3.
The requested surveillance extensions for EDG 1-1-and EDG 1-2 were approved by the'NRC per Amendment Number 105, dated December 8, 1987.
Systems Affected The proposed change affects the Emergency Diesel Generators 1 and 2, but no logic configuration or hardware design modifications have been made.
Safety Function of Systems Affected The two redundant EDGs provide onsite standby power sources to supply their respective 4.16 kV essential busses upon loss of the normal and reserve power sources. Each DBNPS EDG is' comprised of a General Motors (GM), Electro-Motive Division, 20 cylinder, turbocharger, model S20645E4 engine coupled to an Electric Machinery Manufacturing Company 3250 KVA generator.
Each EDG is rated for a speed of 900 rpm, continuous electrical output of 2600 kw and a continuous engine output of'3600 BHP. The EDG vendor is Morrison-Knudsen Company, Inc. Power Systems Division.
Each EDG will receive a starting signal when any of the following occurs:
a.
Loss of-associated 4.16 kV essential bus voltage b.
Safety Feature Actuation System Signal (SFAS) c.
Manual start (local at the EDG engine control relay or idle start /stop panels or control room) d.
Test signals to simulate any of the above
Docket Number 50-346
+' License Number NPF-3 Serial Number 1670 Page 2 Each EDG is equipped with mechanical and electrical interlocks to ensure protection of personnel and to prevent or limit equipment-damage. A loss of essential bus voltage or a SFAS signal vill cause a bypass of all EDG trips except for engine overspeed and generator differential relay action.
The engineered SFAS monitors plant-variables to detect loss of Reactor Coolant System (RCS) boundary integrity and containment high radiation. As dictated by plant conditions, SFAS initiates various engineered safety features.
It also starts both EDGs on an SFAS level 2 actuation (low RCS pressure or high containment pressure).
In addition to the safety-related loads, the EDGs are capable of supplying-power to certain non-safety-related loads for certain plant conditions. The major,~important, non-essential equipment _that may be powered from the EDGs include the following:
Motor-Driven Feed Pump (MDFP) 1-1, which is supplied from a non-essential bus that can be aligned to either EDG, Non-essential makeup pumps, which are supplied from essential buses and are required for feed and bleed cooling of the reactor core.
Unit substation F7, which feeds the Emergency Instrument Air Compressor, and, through Motor Control Center (HCC) F71, feeds the MDFP auxiliaries. Unit substation F7 is fed from the same bus as the MDFP.
Specification 4.0.2 provides allovable tolerances for performing surveillance activities while ensuring that the reliability associated with the surveillance activity is adequate when deviations from the nominal specified interval occur. The tolerance allowed by specification 4.0.2 provides the margin necessary for the opera ional flexibility required by scheduling and c
performance considerations. Specification 4.0.2.a provides a maximum allovable extension of 25 percent for each inspection interval. This provides a maximum 4.5 calendar month extension for 18-month surveillance requirements, resulting in a maximum single interval length of 22.5 calendar months. T.S.
4.0.2.b requires that the total combined interval for any three consecutive tests not exceed 3.25 times the specified surveillance interval. This allows a maximum of 58.5 calendar months for three consecutive test intervals.
Effects on Safety The EDG 18 month surveillance interval was selected to be consistent with the maximum expected interval between refueling outages. It is based on engineering judgment to achieve the dual goals of the need to conduct periodic surveillance tests and to not interfere substantially with unit availability.
Adequate flexibility was provided for these 18 month surveillance requirements to be performed during scheduled refueling outages when a 12 month fuel cycle was used. However, over the years, nuclear core designs have progressed from 12 month fuel cycles to longer operating cycle lengths tn improve unit
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l availability and fuel utilization. With longer operating cycles, coupled with occasional, long refueling, maintenance and modification outages, scheduling of surveillance requirements at an 18-month interval, as required by Technical Specifications, has become increasingly difficult. Furthermore, due to less than optimal plant capacity factors, the time period between refueling outages may exceed 18 months.
Because of this, even though refueling may not be required, plant operation could be constrained by T.S. 4.0.2 compliance.
The performance of the EDG overhaul, as recommended by the manufacturer and required by Technical Specifications, requires considerable time and resources and is difficult to accomplish during a mid-cycle outage of reasonable length.
The EDG inspection performed in accordance with Surveillance Test Procedures DB-SC-03072 (Emergency Diesel Generator 1 Refueling Surveillance Test) and DB-SC-03073 (Emergency Diesel Generator 2 Refueling Surveillance Test) includes over 40 separate maintenance tasks.- To perform the work necessary to satisfy S.R. 4.8.1.1.2.d.1 vould require that each diesel be inoperable for a period of approximately one week. This exceeds the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> period allowed by the Action Statement for this Technical Specification. Even in modes 5 and 6 T.S. 4.8.1.2 requires that one EDG always be available, so that necessary work on the EDGs could not be performed concurrently during a mid-cycle outage.
A recent evaluation was performed by the Morrison-Knu'isen Company, Incorporated, to quantify the effect of extending the EDG surveillance interval of 22.5 months (including the 25 percent allovable extension) by 7.5 months to 30 months. The results are presented below.
The Morrison-Knudsen Company report (No. 6993-2,Rev. 1) addresses all of the items in the Diesel Generator 18-month Maintenance Schedule in DB-SC-03072 and DB-SC-03073. The report concurs with extending approximately 40% of the scheduled maintenance items to a 30 month interval contingent upon increased performance trending of selected parameters identified by the manufacturer.
These parameters are to be monitored during the monthly load test required by T.S. 4.8.1.1.2.a. Per the manufacturer's concurrence, satisfactory results from the trending an lysis vill justify performance of the extended items at a maximum of 30 months. Trending results which show unacceptable performance l
vill require remedial action. The manufacturer concurs with extending approximately another 40% of the items on the 18-month maintenance schedule to a 30 month interval based upon the manufacturer's experience with this class of standby electrical equipment and the past reliability of the EDGs at DBNPS.
The remaining 20% of the maintenance items, such as filter changes,-are nov required to be scheduled more frequently, at intervals of less than 18 months, (i.e., annually in most cases).
The augmented performance trending program requires a more extensive analysL l
of the lube oil samples taken during the EDG monthly load test. Additionally.
the EDG monthly load test provides data on cylinder exhaust temperature, crankcase pressure, KV, voltage, frequency, generator temperature, cooling water expansion tank level, action of the air start motors, and pressure and temperature of the lube oil, engine cooling vater and fuel. The Preventive Maintenance program has been updated to incorporate the manufacturer's recommendations. The EDG Monthly Test Procedures (DB-SC-03070 and l
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DB-SC-03071) are to be updated to incorporate the manufacturer's recommendations by June 30, 1989. This date is well in advance of the earliest 18 month surveillance due date of January 8, 1990.
An evaluation of past operating experience at Davis-Besse, in addition to the evaluation performed by Horrison-Knudsen Company, Inc., has shown that the EDGs are highly reliable. EDG availability in the last 100 starts has been 1
i very good, as indicated by only one failure to start (reliability of 0.99/ demand) for EDG 1-1 and no failures to start (reliability of 1.00/ demand) for EDG 1-2.
More recently, there have been no failures to start for either unit in the past 50 starts. This individual EDG performance exceeds the NRC performance standard proposed in Generic Letter 84-15 dated July 2, 1984, regarding Station Blackout. The combined performance of both of DBNPS EDGs of 0.995/ demand surpasses the industry average for EDG reliability of 0.98/ demand referenced in the same document. By incorporating the manufacturer's recommendations, this high level of reliability will be maintained even with a 30 month surveillance interval.
The proposed amendment stipulates that the provisions of Specification 4.0.2 vould not apply to S.R. 4.8.1.1.2.d.1.
Experience has shown that this EDG surveillance is not needed as frequently as required by these specifications in order to reliably ensure EDG operability. The results of previous inspections for EDG 1-1 and EDG 1-2, after extended inspection intervals of 27 and 26.5 months, respectively, (permitted by T.S. amendment 105) demonstrated satisfactory condition.
Furthermore, the EDGs showed no indications of unusual wear of the components which were recommended for examination by the manufacturer.
Since the EDGs are used only for standby service and operate very few hours between overhauls, engine year is minimal.
It is concluded that Specification 4.0.2 applicability to S.R.
4.8.1.1.2.d.1 is no longer necessary with this proposed change.
Unreviewed Safety Question Evaluation Toledo Edison has performed a safety review and evaluation of these proposed changes. The conclusions of the evaluation for an unreviewed safety question follow:
The proposed action vould not increase the probability of an accident previously evaluated in the USAR because the EDGs are standby equipment which do not contribute to the occurrence of any USAR accident.
The proposed action vould not increase the consequences of an accident previously evaluated in the USAR because the ability of the EDGs to respond and operate as required vill not be degraded, based on an evaluation performed by the manufacturer and compliance with their recommendations. The EDGs vill continue to be tested monthly, as required by S.R. 4.8.1.1.2.a of the Technical Specifications. Therefore, no consequences of an accident would be affected, since the equipment vill still function properly and the accident response vill be as assumed in the USAR.
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' License Number NPF-3 Serial Number 1670 Page 5 The proposed action vould not increase the probability of a malfunction of equipment important to safety.
Compliance with the manufacturer's l
requirements ensures the probability of EDG malfunction is not increased. The proposed change does not involve any other equipment. The proposed change vill not prevent any system from functioning as assumed in the USAR.
The proposed action would not increase the consequence of a malfunction of equipment important to safety because the proposed amendment does not involve a modification to any system (s) or a change in operation of existing system (s). The consequences of equipment malfunction remain as originally analyzed.
The proposed action vould not create the possibility for an accident of a different type than any evaluated previously in the USAR because the EDGs, the only equipment affected, cannot initiate an accident. Furthermore, proper operability of the EDGs is still assured and all failure modes are the same as previously analyzed.
No new accident would be created by this Technical Specification change.
The proposed action vould not create a possibility for a malfunction of equipment of a different type than any evaluated previously in the USAR because no equipment is being added or modified. Only the EDGs are affected, and, by complying with the manufacturer's requirements, they are not subject to any new malfunctions. Therefore, no new malfunction of equipment will occur.
The proposed action vould not reduce any margin of safety as defined in the basis for any Technical Specification because all the assumptions in the USAR analyses are unchanged and the EDG's reliability is maintained. Since equipment reliability will be maintained, the margin of safety will also be maintained. No Limiting Condition for Operation (LCO) or Limiting Safety System Setpoint (LSSS) is affected.
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Conclusion Based on the above, it is concluded that the proposed Technical Specification changes do not constitute an unreviewed safety question.
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