ML20215L972
| ML20215L972 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 05/06/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20215L970 | List: |
| References | |
| NUDOCS 8705130036 | |
| Download: ML20215L972 (5) | |
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,u SAFETY EVALUATION BY THE~0FFICE OF NUCLEAR REACTOR REGULATION, p
RELATED TO AMENDMENT NO. 71 TO FACILITY-0PERATING LICENSE NPF-9 AND-AMEhDMENT NO. 52 TO FACILITY OPERATING LICENSE NPF-17 DUKE POWER COMPANY DOCKET NOS. 50-369 AN*.' 50-370 McGUIRE NUCLEAR STATION, UNITS 1 AND 2 INTRODUCTION By letter dated July 10, 1985, as revised April 15, 1986 and supplemented and clarified October 30 and November 21, 1986, Duke Power Company (the licensee) requested changes to the Technical Specifications (TSs) regarding testing and surveillance of diesel generators (D/Gs) and diesel fuel oil at McGuire Nuclear. Station, Units 1 and 2.
The requested changes are associated with four separate aspects:
(1) changes pursuant to NRC Generic Letter (GL) 84-15; J
(2) changes pursuant to GL 83-30; (3) a change to separate the 24-hour run test and the Engineered Safety Features (ESF) actuation test; and (4) addition of an alternate diesel fuel oil viscosity measuring-unit.
EVALUATION
't A. Changes Pursuant to GL 84-15 On July 2,1984, the Commission issued GL 84-15, " Proposed Staff actions to Improve and Monitor Diesel Generator Reliability." In GL 84-15 the Comission-noted its finding that excessive D/G testing contributed to premature engine degradation and that an overall improvement in reliability and availability 4
can be gained by eliminating excessive fast starts. Typical TSs were included in GL 84-15. The licensee has in general used the staff's guidance outlined in GL 84-15 and the associated TSs as previously approved by the Commission for the North Anna Power Station as a basis for the proposed changes to the McGuire D/G Action Statements and Surveillance Requirements.
Action Statements 3.8.1.la.b.d, and e are changed to require that the oper-ability of a D/G be demonstrated by both starting it and running it loaded or.
the'offsite power system.
Prior to this amendment, the TSs required that the D/G only be started. The requirement to load the machine is made to reduce the amount of D/G operating time under detrimental no-load or light-lcad con-ditions. We find these changes to be in the interest of reducing operation of the D/G under conditions which are known to produce detrimental effects. These changes are, therefore, acceptable. These changes are also in accordance with previously approved TSs on North Anna.
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8705130036 870506 PDR ADOCK 05000369 P
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s 2-Action statement 3.8.1.la is changed to delete the requirement to demonstrate
-the D/Gs operable for loss of an offsite circuit, provided they have been successfully tested within.the past 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
testing and, thereby, the associated detrimental effects of frequent startsThis ch and is, therefore, acceptable.- This change is also in accordance with previously approved TSs on. North Anna.
Action statements 3.8.1.la,b d and e are changed to expand the length of time allowed to demonstrate a diesel generator operable.
The. time is changed from I hour in all cases, to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> in the case of loss of two power sources site and onsite), and to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for the case of loss of one power source (off-The previous requirement to retest at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is also eliminated.
We find.these changes provide sufficient time to perform an orderly start and loading test on the D/Gs, and reduce unnecessary testing and.thereby the asso-ciated detrimental effects of frequent starts.
4 These changes are, therefore.
acceptable. These changes are also in accordance with previously approved.TSs on North Anna.
' Action statements 3.8.1.Ib and d are changed to eliminate the need to demon-strate the operability 'of a D/G when its redundant counterpart is inoperable due to preplanned testing or maintenance. We find these changes reduce un-necessary testing and, ~thereby, the. associated detrimental effects of frequent starts. These changes are, therefore, acceptable.
These changes are also in accordance with previously approved TSs on North Anna.
Action statements 3.8.1.lb, d and f are supplemented with a footnote stating that a D/G shall be considered to be inoperable from the time of failure un-til it satisfies the requirements of Surveillance Requirements 4.8.1.1.2a.4 and 4.8.1.1.2a.5.
We find that this footnote clarifies OPERABILITY of the D/Gs and is, therefore, acceptable.
Action statements 3.8.1.lb, and d are supplemented with a footnote requiring that surveillance testing on a redundant D/G be completed regardless of when the inoperable D/G is restored'to operability. We find these changes ensure that both D/Gs are tested for common-mode failures which may have caused the j
initial operability of the first D/G. These changes are, therefore, acceptable.
These changes are also in accordance with previously approved TSs on North Anna.
These amendments also add a footnote to Surveillance Requirement 4.8.1.1.2a.4 whose purpose is to. reduce the number of cold fast stirt surveillance tests on the D/Gs from at least once per 31 days to at least once oer 184 days.
All other engine starts and loadings for the purpose of the surveillance testing may be preceded by an engine prelube period and/or other warmup procedures re-comended by the manufacturer so that mechanical stress and wear on the diesel engine is minimized. This change is in response to the staff conclusion in GL 84-15 that the frequency of fast start tests from ambient conditions of D/Gs 3
should be reduced. This proposed TS change follows that guidance and is, 4
therefore, acceptable.
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The amendmen'ts make several changes to Table 4.8-1, " Diesel Generator. Test Schedule." First, the basis for the testing schedule is changed from'a "per nuclear' unit" basis to a "per dier.el generator" basis..From past experience
.we have found.that TSs requiring / licensees to test on a "per nuclear unit"-
-basis has resulted in licensees testing the " good" D/Gs (i.e., D/Gs with favorable test results) to an unnecessary excess. Excessive testing of good
'D/Gs does _not improve their reliability; rather as noted in GL 84-15,.it tends to degrade them and to shorten their overall expected lives. These amendments eliminate the excessive testing of the good D/G.by establishing that the fre-quency of. testing of a D/G is to be based upon its own failures.
The revised l'S is, therefore, more appropriate and is consistent with GL 84-15 guidelines on improving D/G reliability.
Therefore, this change is acceptable.
A second change to Table 4.8-1 by these amendments is that the test frequency is reduced for an individual D/G based on its number of failures in prior tests.
1 The. staff has for some time been evaluating the frequency of D/G testing and the associated potential for severe degradation of engine parts due to frequent fast-start testing.
From these studies, we have concluded that the test fre-
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quency can be reduced to minimize this potential without adversely affecting _
the overall D/G reliability. He find that the reduction in test frequency is 1-consistent with GL 84-15 guidelines on improving D/G reliability and, therefore,
.is acceptable.
A third change in. Table 4.8-1 provides an exolicit direct incentive for the licensee to take major corrective action on the D/G.
If the licensee perfoms E
a thorough and comprehensive complete overhaul of. the D/G that is approved by the D/G manufacturer, the D/G would be rebuilt to like-new conditions.
t Follow-ing such an overhaul, the D/G would become operable after it-successfully passed p
~the appropriate surveillance tests once.
However, in return for the overhaul, the utility receives the benefit of not being required to count previous failures on the D/G if an acceptable reliability can be demonstrated.
With "no previous failures" in the past 20 or 100 tests, the change Demits the D/G to re-enter the test schedule at the monthly test frequency. Accelerated testing (weekly) i would not become required until either 2 failures in 20 tests or 5. failures in
'100 tests occur.
In that major repair action for a D/G that has experienced
, excessive failures has long been the goal, this concept is acceptable.
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- A reliability criterion for the rebuilt D/G is added to Table 4.8-1.
criterion is the successful completion of 14 consecutive tests, at least 4 of This i
which would be " fast cold" starts.
Statistically, the probability that a D/G with an actual reliability of less than 0.90/ demand will satisfy, this 14-test t
criterion is no greater than 20% and this probability decreases rapidly with the actual reliability.
t The probability that a D/G with an actual reliability of less than 0.95 will satisfy the 14-test criterion is 42% or less. We, E
therefore, find the proposed 14-test criterion to be acceptable. One should be careful, however, about repeated attempts to satisfy the 14-test criterion.
In such a case the statistical situation changes.
If a D/G passe.s the cri-terion on a second attempt, the probability that the actual reliability is O.95 would be reduced to only about 25%.
Therefore, if the 14-test criterion is not passed on the first attempt, the previous test failures could not be disposed of until some new criterion is negotiated with the NRC.
This is specifically required as part of the reliability test criterion in Table 4.8-1 and is, therefore, acceptable.
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B.
Changes' Pursuant to GL 83-30, Trior to these amendments, McGuire surveillance Requirement 4.8.1.1.2e.6) re-quired periodic verification that on a simulated loss of the diesel _ generator, with offsite power not available, the D/G loads are shed from the emergency.
busses and-that subseouent loading of the diesel generator occurred in accord-ance with design requirements. By GL 83-30, dated July 21, 1983, the Commission concluded generically that such load shedding / loading was not consistent with the provisions of General Design Criterion (GDC) 17, Regulatory Guide 1.108, and Standard Review Plan Sections 8.2 and 8.3.1 and that TSs with such surveil-lance requirements for this D/G testing should be modified to delete this.
requirement which is in excess of the scope of GDC-17. The deletion of this surveillance is therefore, consistent with the staff request in GL 83-30 and
-is acceptable.
Because of the deletion of Surveillance Requirement 4.8.1.1.2e.6), previous sur-ve111ance Requirement 4.8.1.1.2e.7) is renumbered as 4.8.1.1.2e.6).
Additionally, previous Surveillance Requirement 4.8.1.1.2e.6)c) which addresses the bypassing of all but certain diesel generator trips and certain diesel generator breaker trips, is-reworded for clarity. This is strictly an editorial change that in-volves no change in requirements and is, therefore, acceptable.
C.
Separation of 24 Hour Run Test and Engineered Safety Features Actuation Test The amendments add a new Surveillance Requirement 4.8.1.1.2e.7) which requires that the D/G be operated for one hour at 4000KW (the continuous rating) to
. achieve temperature stability, and then within 5 minutes, that the D/G be re-started and-accident loads be sequenced on it in accordance with newly-numbered Surveillance Requirement 4.8.1.1.2e.6)b). This replaces the previous require-ment that the start and sequence be conducted within 5 minutes of the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> load test specified in Surveillance Requirement 4.8.1.1.2e.8).
The licensee states that performing these tests in quick succession, as previously required oy Surveillance Requirement 4.8.1.1.2e.8), creates a potential for causing
" critical path" complications and delays during an outage. The staff finds that conducting the start and sequencing test after the machine has been oper-ated for one hour at its continuous rating fulfills the intent of conducting the test following the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> load test and is, therefore, acceptable.
(We also note that the Standard Technicel Specifications offers this test as an option.if the diesel generator initially fails the start and sequence test following the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> load test.)
D.
Alternate Measuring Unit for Diesel Fuel Oil Viscosity i
TheamendmentschangeSurveillanceRequirement4.8.1.1.2c.1)b)toallowthe licensee to verify the new diesel fuel oil viscosity by using either Kinematic Viscosity at 40*C (104'F) or Saybolt Universal Viscosity at 100*F (38'C).
Prior to these amendments, the Surveillance Requirement addressed only Kinematic Viscosity expressed in units of centistokes.
ASTM-D975, " Standard Specification for Diesel Fuel Oils," allows fuel oil viscosity to be expressed in the units for Kinematic Viscosity (centistokes) or Saybolt Universal Viscosity (SUS). Even though the temperatures at which i
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ENVIRONMENTAL CONSIDERATION These amendments involve changes to the installation or use of facility com-ponents located within the restricted area as defined in 10 CFR Part 20 and changes in surveillance requirements. The staff has determined that the amend-ments involve no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupational exposure. The NRC staff has made a determination that the amendments involve.
no significant hazards consideration, and there has been no public coment on such finding. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth.in 10 CFR 51.22(c)(9). Pursuant to 10 CFR~
51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
CONCLUSION The Commission made a proposed detemination that the amendments involve no significant hazards consideration which was published in the Federal Register (51 FR 30567) on August 27, 1986 and consulted with the state of North Carolina.
No public comments were received, and the state of North Carolina did not have any connents. Licensee submittals since publication of 51 FR 30567, dated October 30 and November 21, 1986, supplemente and clarify the licensee's tl' request by providing increased confomance of the requested changes with the-NRC generic TS model and.with previously approved (North Anna) TSs, and do not substantively alter the proposed changes as identified in 51 FR 30567 or alter the-staff's proposed no significant hazards consideration determination.
il We.have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will l,
not be endangered by operation in the proposed manner, and (2) such activities l7 will be conducted in compliance with the Comission's regulations, and the issuance of these amendments will not be inimical to the common defense and security or to the health and safety of the public.
l Principal Contributors:
J. Lazevnick, PAEI R. Giardina, PAPS D. Hood, PAD #4 Dated: May 6, 1987
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