ML20237K235
| ML20237K235 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 08/25/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20237K233 | List: |
| References | |
| GL-84-15, TAC-55865, TAC-55866, NUDOCS 8708270111 | |
| Download: ML20237K235 (5) | |
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'o UNITED STATES g
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NUCLEAR REGULATORY COMMISSION gg'
- C WASHINGTON, D. C. 20555 4
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g SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENTS NOS.147 AND 83 TO FACILITY OPERATING LICENSES DPR-57 AND NPF-5 GEORGIA POWER COMPANY OGLETHORPE POWER CORPORATION MUNICIPAL ELEC1RIC AUTHORITY OF GEORGIA CITY OF DALT0fi, GEORGIA EDWIN I. HATCH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-321 AND 50-366
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INTRODUCTION By letter dated March 31, 1986, Georgia Power Company (GPC, the licensee) requested a number of changes to the Technical Specifications (TS) for the Edwin I. Hatch Nuclear Plant, Units 1 and 2.
The proposed changes pertain to the testing of the onsite emergency diesel generators.
The objective of diesel generator (DG) testing is to assure operability of the DG by timely failure detection and corrective actions as necessary.
Such testing provides a degree of assurance of the availability of the DG during the periods between tests. The existing DG testing concept is that assurance of operability has to be demonstrated by more frequent testing (TS) require as the number of DG failures increases. Thus, the Technical Specifications that DGs be tested in accordance with Regulatory Guide 1.108, " Periodic Testing of Diesel Generator Units Used as Onsite Electrical Power Systems at Nuclear Power Plants," with the test interval dependent upon the demonstrated DG performance, i.e., the interval shortens as the number of failures increases. Furthermore, the test interval is established conservatively on a per nuclear unit basis, rather than on a per diesel basis.
The licensee's March 31, 1986, letter requested revisions to the TS that would reduce the required nu.aber of " fast cold" starts of the DGs, eliminate excessive testing of the DGs, reduce the frequency of certain testing that has the potential for causing DG degradation, and modify the basis for the test interval to " failures per diesel generator" rather than "DG failures per nuclear unit."
EVALUATION The changes requested by the licensee are addressed individually.
1.
The licensee proposes to change the test interval frequency such that it is based upon failures per diesel generator rather than DG failures per nuclear unit. The primary purpose of this change is to avoid test starting all diesel generators due to failures experienced on one diesel generator 70ur past experience has shown that many licensees have been 8708270111 870825 PDR ADOCK 05000321 P
PDR; i
. testing their good diesel generators mainly to quickly get out of the frequent test cycles imposed by the Standard Technical Specifications.
The staff and industry consensus is that current requirements for testing of good diesel generators do not improve reliability of the good diesel generators, and may be a factor in potential degradation of the good diesel generators, including negative effects or their overall expected life; hence, such testing is not warranted. Therefore, we concur with the licensee's proposal to reckon diesel generator failures on a per diesel generator basis rather than on a per nuclear unit basis. This is consistent with Generic Letter 84-15 guidelines on diesel generator reliability and is, therefore, acceptable.
2.
The licensee proposes changes to TS Surveillance Requirements 4.9. A.2.a for Unit 1 and 4.8.1.1.2.a for Unit 2 to include routine testing at intervals of 31 days or 7 days based on the number of failures per diesel l
in the last 20 tests. The proposed test interval is based on GL 84-15 which gives a diesel generator reliability goal of 0.95 and is consistent i
with the resolution of ongoing generic issue (GI) B-56 on Diesel Generator Reliability in support of Unresolved Safety Issue (US1) A-44 Station Blackout. This change is, therefore, acceptable.
3.
The licensee proposes to add the definition of Staggered Test Basis as j
stated in the Unit 2 TS to the definitions in the Unit 1 TS. We find this to be acceptable.
4.
The licensee proposes to change the Hatch Unit 1 TS Surveillance Requirements 4.5.A.2, 4.5.B.2, 4.5.C.3, 4.5.G and 4.5.J.2 to eliminate diesel generator testing when core spray, low pressure coolant injection, RHR service water and plant service water systems are declared l
inoperable. Failures experienced in the above mentioned systems do not adversely affect the perfonnance of the diesel generators, although,
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failure of a division of plant service water will cause the diesel
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associated with that division to become inoperable. However, increased j
testing of the redundant diesel generator under such circumstances is not j
required. This proposed change for Hatch 1 is consistent with the
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current Hatch 2 TS, is in accordance with the Standard Technical 1
Specifications, and is, therefore, acceptable.
1 5.
Hatch Unit 2 TS 3.8.1.1 Action Statements presently require that every i
diesel generator be demonstrated to be operable, by performing i
Surveillance Requirement 4.8.1.1.2.a.4, within one hour and at least once 1
per eight hours thereafter in the event an emergency AC power source or i
offsite power source is declared inoperable. GPC proposes to change the l
Action Statements of TS 3.8.1.1 so that:
(a) With one DG or one offsite power source inoperable, the remaining DGs must be demonstrated to be operable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, by performing Surveillance Requirement 4.8.1.1.2.a.4.
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. (b) With two offsite power sources inoperable, the DGs must be demonstrated to be operable within eight hours, by. Derforming Surveillance Requirement 4.8.1.1.2.a.4.
(c) With two DGs inoperable, the remaining DG must be demonstrated to be operable within four hours, by performing Surveillance Requirement 4.8.1.1.2.a.4 The staff concludes that the test frequency can be reduced as proposed by the licensee without adversely affecting the overall diesel generator reliability, is in accordance with Generic Letter 84-15, and is, therefore, acceptable.
6.
The existing Action Statements of TS 3.8.1.1 for Hatch Unit 2 also require that if two DGs are inoperable, at least one of the inoperable DGs must be returned to operable status within two hours. The. licensee proposes to extend the time for restoring operability of one of the DGs from two hours to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This change would leave the unit inadequately protected from a loss of offsite power for a 24-hour period and is not in accordance with the guidelines of Generic letter 84-15 or the staff position on Generic Issue B-N.
It is, therefore, unacceptable.
7.
The licensee also proposes to separate the existing Action Statement a.
of Hatch Unit 2 TS 3.8.1.1 into two new Action Statements, a. and b.,
and renumber existing Action Statements b., c. and d. as c., d. and e.,
respectively. This is an administrates change only and is acceptable.
8.
The licensee proposes changes to Surveillance Requirements 4.9.B.1 and 4.9.B.2 for Hatch Unit I similar to those proposed for Hatch Unit 2
- .iscussed in item 5 above, to reduce testing of the DGs from every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to once within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when an offsite power source or a DC is caclared inoperable. This is in accordance with Generic Letter 84-15 and 13, therefore, acceptable.
9.
The licensee also proposes to add a Surveillance Requirement 4.9.A.1 to the Hatch Unit 1 TS to require verification of offsite power availability l
and breaker alignments every seven days.
Such a requirement is presently l
in Hatch Unit 2 TS Surveillance Requirement 4.8.1.1.1.a.
This change i
would provide added assurance of the availability of offsite power and l
1s, therefore, acceptable.
10.
The licensee proposes changes to Hatch Unit 1 Surveillance Requirement 4.9.A.2.a. and to Hatch Unit 2 Surveillance Requirements 4.8.1.1.2.a.4 and 4.8.1.1.2.a.5 to require verification of operability by starting each diesel generator, loading it gradually, and running the load test for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Hatch Unit 1 TS Surveillance Requirement 4.9. A.2.a.2 and Hatch Unit 2 TS Surveillance Requirement 4.8.1.1.2.b would be changed to require " fast-cold" starts of the DGs once every 6 months. This is in l
accordance with the current Standard Technical Specifications and is, therefore, acceptable.
11.
The licensee proposes to revise the Hatch Unit 1 TS 4.9. A.2.a to include a load range of 1710 Kw - 2000 Kw to preclude the possibility of overloading diesel generators 1A,1B and IC for monthly testing, and load ranges of 2250 Kw-2400 Kw for diesel generators IA and 1C and 2360 Kw -
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2425 Kw for diesel generator 1B for the 184 days fast-cold start testing.
It should be noted that Hatch 1 is not governed by the Standard Technical Specifications; however, the proposed change is an improvement over the existing Technical Specifications and is, therefore, acceptable.
12.
The licensee proposes to revise the Hatch Unit 2 TS 4.8.1.1.2.a.4 to I
include a load range of 1710 Kw-2000 Kw to preclude the possibility of overloading the generator for monthly testing, and to revise TS 4.8.1.1.2.b to specify load ranges of 2764 Kw-2825 Kw for diesel 2A, 2360 Kw-2425 Kw for diesel 1B and 2742 Kw-2825 Kw for 2C for the 184 days i
fast-cold start testing. Table 8.3-6 of the Hatch 2 FSAR lists the load distribution on emergency buses (for loss-of-offsite Power and 0-10 minutes post-LOCA) as 2669 Kw for diesel 2A, 2360 Kw for diesel 18 and 1
2597 Kw for diesel 2C. The continuous rating of each diesel generator is 2850 Kw. Though this proposed revision is a deviation from the Standard f
Technical Specifications (requiring the diesel generators to be loaded to I
their continuous rating-for periodic testing), it is consistent with the j
engineering rationale for 184 days fast-cold start testing (requiring the testing of the diesal generator to the design basis accident conditions)
J included in GL 84-15 and is, therefore, acceptable.
13.
The licensee proposed to revise the Hatch Unit 2 TS Surveillance
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Requirement 4.8.1.1.2.c.9 to require rated load testing of the diesel i
generators during the first 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br /> to allow engine preconditioning and the generators then be subjected to overload condition during the last two hours of the test. This is not in accordance with Regulatory Position C.14 of Regulatory Guide 1.9, " Selection of Diesel Generator Set Capacity for Standby Power Supplies," which states that immediately following the 2-hour short-time load test, load equal to the continuous rating should be applied for 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />. The purpose of this test is to
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demonstrate that the diesel generator is capable of immediately assuming j
the full LOCA load and then carrying the long tenn load for the remainder
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of the 24-hour period. The licensee's proposed test does not accomplish this purpose and it is, therefore, unacceptable.
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14.
The licensee proposes to reduce the test frequency on Hatch Unit 2 for demonstrating that the diesel generator starts at least 5 times from ambient condition and accelerates to synchronous speed in 120 seconds j
using the pressurized air ( 225 psi
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receivers (with compressors secured)g) stored in the two air start The licensee proposes to replace current Surveillance Requirement 4.8.1.1.2.c.14 which requires that this j
test be perfonned once every 18 months with new Surveillance Requirement 4.8.1.1.2.e which would require that the test be performed once every j
five years. The primary reason for this test is to demonstrate adequate
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equipment sizing of the air start system.
It is a test that is usually
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required only during initial startup testing. The current Standard 1
Technical specifications do not require this test, but instead require
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routine surveillance to assure that the pressure in the air start a
receivers is adequate. The Hatch Unit 2 Technical Specifications include this requirement (that the pressure is verified to be 225 psig at least once every 31 days). The licensee has proposed this change in order to
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reduce abusive fast starts of the diesel generator.
On the basis of the j
above discussion, we have concluded that the proposed reduction in fre-quency of this test is desirable and is acceptable.
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. ENVIRONMENTAL CONSIDERATIONS These amendments change a requirement with respect to installation or use of a facility component. located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The staff has determined that the amendments involve no significant increase in the ' amounts, and no signi-ficant change in the types, of any effluents that may be released offsite, and that there should be no-significant increase in individual or cumulative.
occupational radiation. The Commission has previously issued a proposed finding 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 E51.22(c)(10).
Pursuant to 10 CFR Q51.22(b), no environmental impact state-ment or environmental assessment need be prepared in connection with the
~ issuance of the amendments.
CONCLUSION The Comission made a proposed determination that the amendments involve no significant hazards consideration which was published in the Federal Register (51 FR 22237) on June 18, 1986, and consulted with the state of Georgia.
No public comments were received, and the state of Georgia did not have any l
comments.
We have concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (2) such activities will be conducted in compliance with the Comission's regulations, and the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
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Principal Contributors:
L. Crocker N. Trehan I
Dated:
August 25, 1987 1
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