ML20058A664
| ML20058A664 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 06/18/1982 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20058A661 | List: |
| References | |
| NUDOCS 8207010131 | |
| Download: ML20058A664 (3) | |
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SAFETY EVALUATION SAN ONOFRE NUCLEAR GENERATING STATION, UNIT 2 DOCKET NO. 50-361 Introduction By letter dated May 19, 1982, the Southern California Edison Company (SCE), on behalf of its?lf, San Diego Gas and Electric Company, The City of Riverside and The City of Anaheim (the licensees), requested the following changes to the San Onofre Nuclear Generating Station, Unit 2 Technical Specifications:
1.
For Specification 3.3.2 (Engineered Safety Features Actuation System Instrumentation), Table 3.3-5 Items 8.a.(1) and 9.a(1), SCE has requested to change the required Auxiliary Feedwater ( AC Trains) response time from "40.9*" (SEC) to "50.9*/40.9**" (SEC), and to add a new note at the bottom of the table,"**
Emergency diesel generator starting delay (10 seconds)
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is included." This will clarify the required response time testing conditic9s.
2.
For Specification 3.3.3.6, Table 3.3-10 Item 23, SCE has requested that the REQUIRED NUMBER OF CHANNELS be changed from "2/ cold leg" to "l/ cold leg" and the MINIMUM CHANNELS OPERABLE from "l/ cold leg" to "N.A."
By letter dated May 20, 1982, SCE requested the following changes to the San Onofre Unit 2 Technical Specifications:
3.
Items 8.a.(2) and 9.a.(2) of Table 3.3-5 require that the Auxiliary Feedwater Steam /DC Train have a response time of 30.9 seconds and Table 3.3-3 reouf res the Emergency Feedwater Actuation System to be OPERABLE in MODE 3.
SCE has requested that a NOTE (6) be added to Items 8.a(2) and 9.a(2) to read:
"(b) The provisions of Specification 4.0.4 are not applicable for entry into MODE 3".
l By letters dated May 21 and 22, 1982, SCE requested the following changes to the San Onofre Unit 2 Technical Specifications:
4.
Specification 3.3.2, Table 3.3-5, items 2.a(5)(b), 3.a(4)(b), and associated NOTE 4, ENGINEERED SAFETY FEATURE ACTUATION SYSTEM INSTRUMENTATION. *SCE has requested a change to add the requirement to perform response time testing l
of eight containment emergency cooling CCW isolation valves, and modify the i
maximum allowable rasponse time for the CCW non-critical loop isolation valves.
ii The Technical Specifications currently require response time testing of the CCW non-critical loop isolation valves only.
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- Evaluation Our evaluation of the proposed changes indicated above are as follows:
PROPOSED CHANGE 1: The 40.9 second requirement pertains to non-LOCA events which include the emergency diesel generator starting time in the SIAS and pump load sequence delay. Such events are bounded for AFW delivery time by the loss of normal feedwater event and require AFW delivery in 42.7 seconds (40.9 is conservative). Events which require AFW when SIAS is present (e.g.,
small break LOCA) are bounded for AFW delivery time by the (coincident) loss of normal A/C event and require AFW delivery in 53 seconds (50.9 is conservative).
This change therefore makes the applicability of AFW pump load sequence delay to EFAS response time consistent with design basis requirements.
PROPOSED CHANGE 2: The proposed change corrects an error in the Technical Speci fications. The safety analysis is based on one HPSI cold leg flow channel per loop. San Onofre Unit 2 has 4 cold legs and 2 hot legs with one HPSI injection path per cold leg and one required instrument per injection path.
The intent of the specification is to limit the out of service time for any One of these instruments to less than seven days. Therefore, this change is acceptable.
PROPOSED CHANGE 3: The proposed change will allow the facility to enter MODE 3 prior to demonstrating the response time of the steam driven Auxiliary Feedpump.
This is acceptable since the steam driven Auxiliary Feedpump is not required to be OPERABLE prior to MODE 2 per Specification 4.7.1.2.1.a.l.
I PROPOSED CHANGE 4: SCE has stated that the containment emergency cooling CCW isolation valves (HV 6366 through HV 6373) should be included in the Technical Specifications as well as the CCW non-critical loop isolation valves (HV 6212, HV6213, 9V 6218, and HV 6219). Furthermore, SCE noted that the valve response times should be revised to more appropriately reflect system operation. SCE, therefore, proposes to revise the Technical Specifications to include response times for both sets of valves.
The response times of the containment emergency cooling CCW isolation valves and the CCW non-c'.-itical loop isolation valves must be limited by the Technical Specifications in order to assure that the containrent emergency cooling system l
will operate in accordance with the specific assumptions of the containment
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pressure analysis (as described in FSAR Section 6.2, Tables 6.2-25 and 6.2-26).
The containment pressure analyses assume a 33 second delay following the onset of a high energy line break accident before the system is fully operational; i.e., is effective as a containment heat removal mechanism for accident
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The maximum response time for the containment emergency cooling CCW isolation valves (to open) is 23.2 seconds. Since this response time is less than that assumed in the containment pressure response analysis for the system safety function, we conclude that the response times to be included in the Technical Specifications are acceptable.
The maximum response time for the CCW non-critical loop isolation valves (to close) is 21.2 seconds.
It is necessary for these valves to close at the onset of an accident to preserve the integrity of the CCW system and thereby assure the availability of the system safety function. SCE provided an analysis of the CCW surge tank drain time if the non-critical if nes were ruptured as a consequence of a high energy line break accident. The time required to drain the surge tank was conservatively calcuated to be 29.2 seconds. Since the maximum response time of the CCW non-critical loop isolation valve (to close) is less than the calculated CCW surge tank drain time, CCW pump performance will not be impaired and the system safety function will be preserved. Therefore, we conclude that the response times to be included in the Technical Specifications for these valves are acceptable.
Environmental Consideration We have determined that the amendment does not authorize a change in effluent types or total amounts nor an increase in power level and will not result in any significant environmental impact. Having made this determination, we have further concluded that the amendment involves an action which is insignificant from the standpoint of environmental impact, and, pursuant to 10 CFR Section Sl.5(d)(4), that an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared in connection with the issuance of this amendment.
Conclusion Based upon our evaluation of the proposed changes to the San Onofre, Unit 2 Technical Specifications, we have concluded, that:
(1) because the amendment does not involve a significant increase in the probability or consequences of accidents previously considered and does not involve a significant decrease in a safety margin, the amendment does not involve a significant safety hazards consideration; (2) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and (3) such activities will be conducted in compliance with the Comission's regula-tions and the issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public. We, therefore, conclude that the proposed changes are acceptable.
Dated:
JUN 181932 4
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