ML13331B087
| ML13331B087 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/11/1988 |
| From: | Baskin K Southern California Edison Co |
| To: | |
| Shared Package | |
| ML13331B086 | List: |
| References | |
| NUDOCS 8811160219 | |
| Download: ML13331B087 (15) | |
Text
BEFORE THE UNITED STATES NUCLEAR REGULATORY COMMISSION Application of SOUTHERN CALIFORNIA EDISON
)
COMPANY and SAN DIEGO GAS & ELECTRIC COMPANY )
for a Class 104(b) License to Acquire,
)
DOCKET NO. 50-206 Possess, and Use a Utilization Facility as
)
Part of Unit No. 1 of the San Onofre Nuclear )
Amendment No. 156 Generating Station
)
SOUTHERN CALIFORNIA EDISON COMPANY and SAN DIEGO GAS & ELECTRIC COMPANY, pursuant to 10 CFR 50.90, hereby submit Amendment Application No. 156.
This amendment consists of Proposed Change No. 197 to Provisional Operating License No. DPR-13. Proposed Change No. 197 modifies the Technical Specifications incorporated in Provisional Operating License No. DPR-13 as Appendix A.
Proposed Change No. 197 is a request to revise Appendix A Technical Specifications to remove the administrative limit for loading of the diesel generators and allow loading up to the design rating of 6000 kW.
In the event of conflict, the information in Amendment Application No. 156 supersedes the information previously submitted.
8160219 881111 PDR ADOCk 05000206_
-2 Based on the significant hazards analysis provided in the Description of Proposed Change and Significant Hazards Analysis of Proposed Change No. 197, it is concluded that (1) the proposed change does not involve a significant hazards consideration as defined in 10 CFR 50.92, and (2) there is reasonable assurance that the health and safety of the public will not be endangered by the proposed change.
Pursuant to 10 CFR 170.12, the fee of $150 is herewith remitted.
0
-3 Subscribed on this
__L/
day of 1988.
Respectfully submitted, SOUTHERN CALIFORNIA EDISON COMPANY By:
~
~
Kenneth P. Baskin Vice President Subscribed and swo to befo e me this
//-
day of
__/___
OFFICIAL SEAL C. SALLY SEBO Notary Public-California LOS ANGELES COUNTY My Comm. Exp. Apr. 20, 1990 Notary Public 1 nd for the County of Los Angeles, State of California Charles R. Kocher James A. Beoletto Attorneys for Southern California Edison Company By:
James
.Beoletto-
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of SOUTHERN
)
CALIFORNIA EDISON COMPANY
)
and SAN DIEGO GAS & ELECTRIC
)
Docket No. 50-206 COMPANY (San Onofre Nuclear
)
Generating Station Unit No. 1
)
CERTIFICATE OF SERVICE I hereby certify that a copy of Amendment Application No. 156 was served on the following by deposit in the United States Mail, postage prepaid, on the 11th day of November
, 1988.
Benjamin H. Vogler, Esq.
Staff Counsel U.S. Nuclear Regulatory Commission Washington, D.C. 20555 David R. Pigott, Esq.
Samuel B. Casey, Esq.
Orrick, Herrington & Sutcliffe 600 Montgomery Street San Francisco, California 94111 L. G. Hinkleman Bechtel Power Corporation P.O. Box 60860, Terminal Annex Los Angeles, California 90060 Michael L. Mellor, Esq.
Thelen, Marrin, Johnson & Bridges Two Embarcadero Center San Francisco, California 94111 Huey Johnson Secretary for Resources State of California 1416 Ninth Street Sacramento, California 95814 Janice E. Kerr, General Counsel California Public Utilities Commission 5066 State Building San Francisco, California 94102
-2 C. J. Craig Manager U. S. Nuclear Projects I ESSD Westinghouse Electric Corporation Post Office Box 355 Pittsburgh, Pennsylvania 15230 A. I. Gaede 23222 Cheswald Drive Laguna Niguel, California 92677 Frederick E. John, Executive Director California Public Utilities Commission 5050 State Building San Francisco, California 94102 Docketing and Service Section Office of the Secretary U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Jame A.Beo'fetto
DESCRIPTION AND SAFETY ANALYSIS OF PROPOSED CHANGE NO. 197 TO THE TECHNICAL SPECIFICATIONS PROVISIONAL OPERATING LICENSE NO. DPR-13 This is a request to revise Section 4.4, "Emergency Power Periodic Testing" of Appendix A Technical Specifications for San Onofre Nuclear Generating Station, Unit 1 (SONGS 1).
DESCRIPTION OF CHANGES In order to fully integrate the third auxiliary feedwater (AFW) pump into existing plant systems, emergency power must be provided in accordance with design basis requirements.
Proposed Change No. 197 (PCN 197) is a request to remove the existing administrative load limit on the emergency diesel generators (EDGs) to allow the addition of the loads related to the third AFW pump. The existing administrative load limit does not contain sufficient margin to allow incorporation of the third AFW pump loads.
PCN 197 allows loading of the diesels up to the design rating and revises surveillance testing requirements to ensure the EDGs are tested to the maximum design load.
EXISTING TECHNICAL SPECIFICATIONS See Attachment 1 PROPOSED TECHNICAL SPECIFICATIONS See Attachment 2 SIGNIFICANT HAZARDS CONSIDERATION ANALYSIS As required by 10 CFR 50.91(a)(1), this analysis is provided to demonstrate that a proposed license amendment to implement technical specifications associated with removal of the administrative EDG load limit and allow loading up to the design rating at SONGS 1 represents a no significant hazards consideration. In accordance with the three factor test of 10 CFR 50.92(c),
implementation of the proposed amendment was analyzed using the following standards and found not to: 1) involve a significant increase in the probability or consequences of an accident previously evaluated; or 2) create the possibility of a new or different kind of accident; or 3) involve a significant reduction in a margin of safety.
Discussion:
By letter dated June 22, 1988 and supplemented by letters dated July 15, 19, 21 and 22, 1988, SCE submitted a request to raise the EDG administrative load limit from 4500 kW + 5% to 5250 kW + 5%. This increase was necessary to account for calculational errors discovered during EDG load calculation revisions that were being made to incorporate the third AFW pump loads.
The proposed increase did not account for loads associated with the third AFW pump that will be installed during the next refueling outage. By letter dated July 22, 1988, the NRC approved the load increase on an interim basis subject to certain conditions which were incorporated into SONGS 1 Provisional Operating License.
-2 The installation of the third AFW pump during the next refueling outage will result in additional loads on the EDGs.
Currently, the administrative load limit for the EDGs does not contain sufficient margin to allow adding the new loads without being exceeded. In lieu of requesting a license amendment to increase the administrative load limit only to account for the addition of these loads, SCE requests the current loading restriction be removed and allow the EDGs to be loaded to the design capacity. Based on the following, it is SCE's position that the EDGs can be safely operated at the design limit of 6000 kW.
SONGS 1 utilizes two Delaval Model DSRV-20 diesel generators for on-site emergency power. These diesel generators have a nameplate rating of 6000 kW and operate at 450 rpm. In 1984, the NRC imposed a loading limit on the diesel generators of 4500 kW + 5%. This loading limit was imposed in consideration of certain design issues associated with Delaval diesel generators (see NUREG-1216, "Safety Evaluation Report Related to Operation and Reliability of Diesel Generators Manufactured by Transamerica Delaval, Inc.").
SCE has provided comprehensive analyses of engine performance history, and taken corrective actions to ensure diesel generator reliability and operability. The diesel generator analyses were performed using the nameplate rating of 6000 kW. As stated in NUREG-1216, the basis for derating the diesel generators to less than rated capacity is due to component stresses and potential failure mechanisms associated with the crankshaft and piston skirts.
The potential failure mechanisms for these components and the corrective actions taken to correct these deficiencies are discussed below.
- 1. Crankshaft Cracking The crankshaft in each of the SONGS 1 diesel generators is subjected to three closely spaced resonant vibratory peaks during engine startup and coastdown. The vibratory conditions corresponding to these peaks form a band of high stresses that can induce cracks in certain main journal oil holes. Consequently, crankshaft torsional stresses under startup and coastdown transients have been identified as the mechanism for crack initiation and propagation. In relation to steady state operation, power level has been demonstrated to not induce crankshaft cracking. Further, steady state operation will only contribute to crack propagation if there is a pre-existing crack of sufficient size.
In evaluation of crack propagation, FaAA analyzed the crankshaft at the diesel generator nameplate rating of 6000 kW. The results of the analysis concluded that a certain crack depth (18 mils) must be achieved before steady state stresses will induce propagation. Based on a highly conservative evaluation, the required crack depth could be achieved after completing on the order of 100 start/stop cycles subsequent to the crack growth to a detectable depth (approximately 10 mils).
That is, at the point the crack becomes detectable by nondestructive examinations, an additional 100 start/stop cycles could increase the crack depth to a point where steady state stresses (at 6000 kW) could propagate the crack. Based on actual operating experience, several hundred start/stop transients were necessary to initiate cracking.
-3 As part of the NRC approval to increase the administrative load limit from 4500 kW to 5250 kW, certain license conditions relating to the diesel generator crankshafts were imposed. These conditions are as follows:
(a) Main journals no. 8 and 9 on diesel generator no. 1, and main journals no. 9 and 10 on diesel generator no. 2 are to be inspected prior to plant operation and found to be free of cracks.
(b) Journals no. 8 through 12 on both diesel generator units are to be inspected at the next refueling outage and each subsequent refueling outage until the issue of crankshaft cracking has been resolved.
(c) All diesel starts for testing and surveillance will be slow starts (greater than 24 seconds duration) except for the fast start required by Technical specification 4.4.F conducted once per 18 months during shutdown and any other fast start required following specific maintenance involving the fast start capability.
SCE has completed condition (a) and found the crankshafts to be free of cracks. Condition (b) will be implemented on a continuing basis until resolution of the issue of crankshaft cracking. In compliance with condition (c), SCE performs slow starts as specified. Based on compliance with these conditions, and the limited effect of increased loading of the diesel generators on the propensity for crack initiation and propagation in relation to start/stop evolutions, it is SCE's position that sufficient controls exist to identify and correct detectable cracks well before steady state stresses at the design rating (6000 kW) could induce propagation. Consequently, PCN 197 is concluded to have no significant impact on crankshaft steady state stresses and potential crack propagation.
- 2. Piston Skirt Cracking As part of the NRC approval to increase the administrative load limit from 4500 kW to 5250 kW, a license condition to replace the existing modified type AF piston skirts with type AE during the next refueling outage was imposed. The type AE piston skirts have been ordered and will be installed in both diesel generators during the next refueling outage.
The type AE piston skirts have been qualified for full load operation of the diesel generators. Therefore, replacement of the modified AF piston skirts with type AE will eliminate this potential failure mechanism.
Based on the above, SCE considers that the changes proposed by PCN 197 to allow operation of the EDGs at the design rating will not impact the diesel generator operability or reliability.
-4 Analysis Conformance of the proposed amendments to the standards for a determination of no significant hazard as defined in 10 CFR 50.92 (three factor test) is shown in the following:
- 1. Will operation of the facility in accordance with this proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
RESPONSE: NO The changes proposed by PCN 197 relate to an increase in the calculated diesel generator loading.
The diesel generators are utilized in events following a loss of offsite power to provide electrical power for emergency equipment to achieve a safe shutdown condition. In relation to the probability of a Station Blackout event, it is noted that Station Blackouts result from failure of the diesel generators to start.
Because PCN 197 does not impact the method or ability to start the diesel generators, and that the diesel generators have been analyzed for operation at greater than the limit proposed by PCN 197, this change does not impact the probability of a Station Blackout. Therefore, a revision of the diesel generator load has no impact on the accident probabilities.
PCN 197 potentially impacts only the consequences of previously analyzed accidents.
The analyses performed by FaAA assumed diesel generator loading at, or greater than, the nameplate rating for the SONGS 1 diesel generators (6000 kW).
Although PCN 197 increases the allowable loading up to the design rating, the diesel generators have been analyzed for operation at this level and determined to be acceptable. This change has minimal impact on the diesel generator crankshafts since cracking is induced through start/stop evolutions.
PCN 197 does not impact this aspect of EDG operation.
The existing piston skirts will be replaced with piston skirts fully capable of operation at the design rating. Thus, the potential failure mechanisms associated with the crankshafts and piston skirts will not cause a failure of the diesel generators.
The recommended maintenance and inspections are not affected by this change. Therefore, the potential impact on the consequences of the accidents remain bounded by the previous analyses and the existing programmatic recommendations. Accordingly, operation of the facility in accordance with PCN 197 will not significantly increase the probability or consequences of an accident previously evaluated.
- 2.
Will operation of the facility in accordance with this proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
-5 RESPONSE: NO The diesel generators provide a mitigation function in response to an accident. They will not initiate or create an accident. The changes proposed by PCN 197 relate to the maximum load that can be placed on the diesel generators for surveillance and emergency applications. This maximum load remains within the bounds of previous analyses. Therefore, operation of the facility in accordance with this proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?
RESPONSE: NO The margin of safety associated with diesel generator loading is established by the analyses performed by FaAA. This margin has been increased by the NRC through the imposition of an administrative load limit. The administrative limit was based on the required emergency service loads which were previously calculated to be less than 4500 kN. In addition, previous surveillance testing was performed at loads that approximate the service requirements.
Consequently, an administrative limit was imposed that was (1) consistent with current surveillance testing, (2) accounted for emergency service requirements, and (3) minimized the stresses placed on diesel generator components. This administrative limit was not considered in the context of future diesel generator load changes.
PCN 197 removes the existing administrative load limit and allows loading up to the diesel generator nameplate rating. As discussed previously, the diesel generators have been analyzed to their nameplate rating of 6000 kN, (or greater than 6000 kW for some components).
Analyses have demonstrated that start/stop evolutions are the mechanism that induces crankshaft cracking. PCN 197 does not impact this aspect of diesel generator operation. The piston skirts will be replaced with fully qualified piston skirts capable of operation at the nameplate rating. Thus, the changes associated with PCN 197 do not impact the margin of safety associated with the crankshafts or piston skirts. Accordingly, PCN 197 does not impact the margin of safety assumed in the previous analyses and it is concluded that operation of the facility in accordance with this proposed change will not significantly reduce the margin of safety as defined by the previous analyses.
-6 SAFETY AND SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION Based on the Safety Evaluation, it is concluded that:
(1) Proposed Change No. 197 does not involve a significant hazards consideration as defined by 10 CFR 50.92; and (2) there is reasonable assurance that the health and safety of the public will not be endangered by the proposed change. - Existing Specifications -
Proposed Specifications MJT:0461n
0 0
ATTACHMENT 1 EXISTING TECHNICAL SPECIFICATION 4.4
4.4 EMERGENCY POWER SYSTEM PERIODIC TESTING APPLICABILITY:
Applies to testing of the Emergency Power System.
82 11/7/84 OBJECTIVE:
To verify that the Emergency Power System will respond promptly and properly when required.
SPECIFICATION:
A. The required offsite circuits shall be determined OPERABLE at least once per 7 days by verifying correct breaker alignments and power availability.
84 B. The required diesel generators shall be demonstrated 11/14/84 OPERABLE:
- 1. At least once per 31 days on a STAGGERED TEST BASIS by:
- a. Verifying the diesel performs a DG SLOW START 105 from standby conditions, 7/22/88
- b.
Verifying a fuel transfer pump can be started and 34 transfers fuel from the storage system to the day 4/1/77
- tank,
- c. Verifying the diesel generator is synchronized 105 and running at 4500 kW +/- 5% for > 60 minutes, 105 to include a brief load increase to 7/22/88 5250 kW +/- 5%,
- d. Verifying the diesel generator is aligned to provide standby power to the associated emergency
- buses, 34
- e. Verifying the day tank contains a minimum of 4/1/77 290 gallons of fuel, and
- f. Verifying the fuel storage tank contains a minimum of 37,500 gallons of fuel.
- 2. At least once per 3 months by verifying that a sample of diesel fuel from the required fuel storage tanks 84 is within the acceptable limits as specified by the 11/14/84 supplier when checked for viscosity, water and sediment.
C. AC Distribution
- 1. The required buses specified in Technical Specification 3.7, Auxiliary Electrical Supply, shall be determined OPERABLE and energized from AC sources other than the diesel generators with tie breakers open between redundant buses at least once per 7 days 34 by verifying correct breaker alignment and power 4/1/77 availability.
SAN ONOFRE -
UNIT 1 4-51 7/27/88
- 2. Simulating SISLOP*, and:
84
- a. Verifying operation of circuitry which locks 11/14/81 out non-critical equipment,
- b. Verifying the diesel performs a DG FAST START 105 from standby condition on the auto-start signal, 7/22/88 energizes the emergency buses with permanently connected loads and the auto connected emergency loads** through the load sequencer (with the exception of the feedwater, safety injection, charging and refueling water pumps whose respective breakers may be racked-out to the test 84 position) and operates for > 5 minutes while its 11/14/8 generator is loaded with the emergency loads,
- c. Verifying that on the safety injection actuation signal, all diesel generator trips, except engine overspeed and generator differential, are automatically bypassed.
95 7/3/86
- 3. Verifying the generator capability to reject a load
/4 of 3220 kW without tripping.
11/14/8 SISLOP is the signal generated by coincident loss of offsite power (loss of voltage on Buses 1C and 2C) and demand for safety injection.
The sum of all loads on the engine shall not exceed 5250 kW + 5%.
105 7/22/88 SAN ONOFRE -
UNIT'l 4-54 7/27/88
Basis:
The normal plant Emergency Power System is normally in continuous operation, and periodically tested.( 1 )
34 The tests specified above will be completed without any 4/1/77 preliminary preparation or repairs which might influence the results of the test except as required to perform the DG SLOW START test set forth in T.S. 4.4.B.l.a. The tests will demonstrate that components which are not normally required will respond properly when required. Test loading of the generator to 4500 kW and 5250 kW corresponds to approximate engine brake mean effective pressures of 116 psi and 135 psi, respectively.
DG SLOW STARTS are specified for the monthly surveillances in order to reduce the cumulative fatigue damage to the engine crankshafts to levels below the threshold of detection under a program of augmented inservice inspection. In the event that the DG SLOW START inadvertently achieves steady state 105 voltage and frequency in less than 24 seconds, the 7/22/88 surveillance will not be considered a failure and require restart of the diesel generator.
The monthly surveillance specified by T.S. 4.4.B.l.c includes a "brief" load increase to 5250 kW +/- 5%. This requirement verifies the ability to function under the maximum possible loading conditions. A "brief" test is required to demonstrate operability while minimizing the increased stresses from the higher load.
The duration of this test is expected to be approximately three to five minutes.
The surveillance requirements for demonstrating the OPERABILITY of the station batteries are based on the recommendations of Regulatory Guide 1.129, "Maintenance, Testing, and Replacement of Large Lead Storage Batteries for Nuclear Power Plants," February 1978, and IEEE Std 450-1980, "IEEE Recommended Practice for Maintenance, Testing, and Replacement of Large Lead Storage Batteries for Generating Stations and Substations."
Verifying average electrolyte temperature above the minimum for which the battery was sized, total battery terminal 84 voltage on float charge, connection resistance values and the 11/14/84 performance of battery service and discharge tests ensure the effectiveness of the charging system, the ability to handle high discharge rates and compares the battery capacity at that time with the rated capacity.
Table 4.4-1 specifies the normal limits for each designated pilot cell and each connected cell for electrolyte level, float voltage and specific gravity. The limits for the designated pilot cells float voltage and specific gravity, greater than 2.13 volts and.020 below normal full charge specific gravity or a battery charger current that has stabilized at a low value, is characteristic of a charged cell with adequate capacity. The normal limits for each SAN ONOFRE -
UNIT 1 4-56 7/27/88