ML20212R648
| ML20212R648 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/09/1987 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20212R630 | List: |
| References | |
| GL-84-15, TAC-54698, TAC-54699, TAC-61516, TAC-61517, NUDOCS 8704270299 | |
| Download: ML20212R648 (7) | |
Text
m.
e
.a.
6 na aq o
UNITED STATES 8
~,is NUCLEAR REGULATORY COMMISSION WASHINGTON D.C.20566
%,...../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT N0. 59 TO FACILITY OPERATING LICENSE NO. NPF-10 AND AMENDMENT NO. 48 TO FACILITY OPERATING LICENSE NO. NPF-15 SOUTHERN CALIFORNIA EDISON COMPANY, ET AL.
SAN ON0FRE NUCLEAR GENERATING STATION, UNITS 2 & 3 DOCKET NOS. 50-361 AND 50-362
1.0 INTRODUCTION
Southern California Edison Company (SCE), on behalf of itself and the other licensees, San Diego Gas and Electric Company, The City of Riverside, California, and The City of Anaheim, California, has submitted 'a number of applications for license amendments for San Onofre Nuclear Generating Station (SONGS), Units 2 and 3.
The NRC staff's evaluation of one of these applications, designated PCN-192, is described below.
In PCN-192, SCE (the licensee) has requested a number of changes to Section 3/4-8 of the Technical Specifications (TS) for San Onofre Nuclear Generating Station (SONGS), Units 2 and 3.
The requested changes are in three major categories, as follows:
- 1) changes to Emergency Diesel Generator (EDG) testing) frequency and methodology and other responses to Generic Letter 84-15, 2 changes to the TS requirements for diesel fuel oil surveillance monitoring, and 3) a revision of the TS Action Statements regarding a loss of offsite power (LOOP) to reflect the two offsite power sources provided for each 4160 VAC (4kv) safety bus. Details of the requested TS changes were submitted as an enclosure to the licensee's letters dated March 17, 1986 and June 13, 1986. Supplemental information was forwarded as Enclosures 1 and 2 to the licensee's letter dated September 30, 1986.
The following is the staff evaluation of the infomation provided by the licensee in support of the proposed TS changes.
2.0 BACKGROUND
The staff has, for some time, been studying EDG performance with a view towards identifying problem areas and, subsequently, improving overall EDG reliability.
For the most part, this effort has been conducted as an integral part of Generic Issue B-56, which is still active. While not e
A K
l g
P
p;
-..... a.w.
w w..w.
complete, one result of this on-going study has been staff recognition that the methodology and frequency of EDG-testing may be significant con-tributors to decreased EDG reliability. Consequently, in July, 1984, the staff issued Generic Letter 84-15. The principal objectives of this let ;
ter were to advise utilities of the staff's concerns, to recommend a decrease in the number of " fast starts" experienced by EDG's, and to recommmend a decrease in the required frequency of EDG testing as a function of the number of failures in the last 100 start attempts.
Utilities were encouraged to request changes to the TS covering EDG testing for their individual plants to. reflect the staff's concerns /
recommendations.
In addition to EDG testing Generic-Letter 84-15 also contained a request that all utilities provide historical data on EDG performance at their plants along with details of their individual EDG reliability improvement programs. Sample Technical Specifications for use as guidance by utilities were included as attachments to Generic Let-ter 84-15. Also included was a reference to a need for establishing a maximum cumulative inoperability time (per calendar year) for EDG's, and to increasing the Standard TS Limiting Condition for. Operation (LCO) beyond 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. However, these issues were not addressed at length..and no specific recommendations or sample times were provided. This evalua -
tion deals, in part, with the licensee's response to the generic letter.
This evaluation also addresses proposed changes.to the SONGS 2 & 3 TS requirements for diesel fuel oil surveillance.
In 1984, the staff reviewed and accepted a major change to.the TS requirenents for diesel fuel oil surveillance at McGuire Nuclear Station, Units 1 and 2.
This change, subsequently referred to as the McGuire TS, is considered to be a.
very substantial improvement over the diesel fuel oil surveillance require.
ments in the Standard TS.
It provides for more effective monitoring of.
the condition of stored diesel fuel while making the monitoring task easier.
Pending' inclusion in the Standard TS, the staff has been accepting the use of the McGuire TS on a plant specific basis. The second part of this evaluation deals with the licensee's proposal to change the diesel fuel oil TS surveillance requirements to be similar to McGuire.
In the third part of this evaluation, the staff addresses the licensee's proposal to change the TS Action Statements relative to availebility of offsite pcwer. This issue is specific to SONGS 2 & 3 and does not have any generic background. Details of the licensee's proposal are discussed, further in a subsequent section of this evaluation.
3.0 STAFF EVALUATION 3.1 Generic Letter 84-15 The 1,1censee's proposal in response to Generic Letter 84-15 involves four separate changes. One change is to reduce the frequency of EDG fast starts (from ambient conditions to rated speed and voltage in 10 seconds or less) required from once every 31 days to once every 184 days. This proposed change is covered by a footnote in the
t.
revised TS provided by the licensee as part of PCN-192 documentation.
The footnote also includes provisions for engine prelube and warmup prior to EDG testing except for the test every 184 days. The foot-note is applicable to surveillance requirements 4.8.1.1.2.a.4,5,- and.
4.8.1.1.2.d.8.
The licensee's proposal is consistent with the staff's position regarding the reduction of fast starts to improve EDG relia-bility and is, therefore, acceptable. While acceptable. the licen-see's proposal could include additional actions to reduce wear on diesel engines. Specifically, the staff recourends prelubing prior to all PLANNED starts (including the fast start every 184 days), and loading of EDG's in accordance with vendor recommendations for all testing except those to demonstrate EDG capability to accept and carrysafety. loads (LOOPtest). The licensee should consider these' additional staff recomendations with a view towards further TS changes.
A second proposed change is to reduce the required frequency of EDG testing as a function of the number of failures (to start) in the last 100 attempts. At present, the required testing frequency in-creases in steps from every 31 days to every 14 days: to every
. seven days and, finally, a maximum frequency of every thre'e days.
based on the number of failures. Testing frequency decreases in the reverse order of increasing number of failures.. However, since the requirement is based on the last 100 start attempts, it is possible to stay in the 3 day interval for an extended period of tire. The staff has determined that such accelerated testing can be detri-mental to diesel engines. The licensee has proposed a schedule for testing which would 1) reduce the maximum frequency of testing from once every three days to once every seven days and 2) change the basis for testing frequency from the last 100 start attempts to the last 20 start attempts. The interim step of testing.once every 14 days is deleted. The specifics of when testing frequency is increased to once every seven days and when it reverts back to every 31 days are included in Table 4.8.1 of the licensee's proposed TS. The licensee's proposal is consistent with the recomendations of Generic Letter 84-15 through Table 4.8.1.
However, the licensee's proposal stops at Table 4.8.1, while the generic letter continues with Table 4.8.2 and Attachments 1 and 2 to Table 4.8.1.
Table 4.8.2 contains provisions for additional reliability actions should the number of EDG failures increase beyond the limits stated in Table 4.8.1.
Attachments 1 and 2 contain reporting requirements and EDG requalification guidance, respectively.
In response to staff questions regarding the absence of Table 4.8.2 and Attachments in i
l
y 4.-
their proposed TS, the licensee stated that the same information was contained in their Diesel Generator Reliability Improvement Program which was submitted as an enclosure to the licensee's letter, M.0.
Medford to D.G. Eisenhut, dated October 1, 1984. Based on the licensee's submittal and the subsequent information regarding their s
reliability improvement program, the staff finds that the licensee's proposed TS change is consistent with the staff position regarding a reduction in the total number of EDG tests and is, therefore, acceptable.
A related change to the TS would reduce the number of EDG tests.
The licensee proposes to change Action Statements a, b, and d under LCO 3.8.1.1 as follows.
For statements a and b, the requirement to test the EDG's within one hour and at least once per eight hours thereafter is deleted, and a requirement to test the EDG's once within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is substituted.
For statement d, the requirement to test EDG's within one hour and at least once per eight hours thereafter is deleted and a requirement to test the EDG's once within-eight hours is substituted. This change is not a recommendation from Generic Letter 84-15. However, the staff has determined that this change is consistent with the intent of the generic letter. regarding the reduction of total EDG tests and is, therefore, acceptable.
A third proposed change would impose a limit on the total time an EDG could be inoperable, for any reason, on a calendar year basis. The licensee has proposed a cumulative inoperability limit'for each unit (two EDG's per unit) of 800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> per year. The licensee's proposal is consistent with the provisions of Generic Letter 84-15 to the extent that it addresses allowable cumulative inoperability. However, the staff does not agree with the licensee's justification for 800 hours0.00926 days <br />0.222 hours <br />0.00132 weeks <br />3.044e-4 months <br /> per year and finds the licensee's proposal not acceptable based on the infomation provided to date.
A related proposed change under Generic Letter 84-15 would extend the allowable time to restore an EDG or offsite power source to operable status (LCO) from three days to seven days. The staff also finds this proposed change not acceptable based on the information provided to date.
The staff is taking no action corcerning these two changes as part of ths amendment. If the licensee wishes to pursue these changes, i
it should submit a comprehensive reliability analysis of the AC power system that would define the impact of these changes on the AC power system reliability, compared to the reliability of the current system based on historical operating data. To be acceptable, this analysis must show that the proposed changes do not have a significant adverse impact on AC power system reliability.
l l
~ ~ ~.
1.
- o. 3.2 Diesel Fuel Oil Surveillance Requirements In the existing TS for SONGS 2 & 3 there is a requirement to test the diesel fuel in the storage tanks in accordance with ASTM D-2274 for indications of degradation. The licensee has proposed to sub-stitute ASTM D-2276 for ASTM D-2274 and has provided the following rationale. Testing in accordance with ASTM D-2274 has only limited value with regard to determining the acceptability of fuel oil for use in diesel engines because test results are only an indication of the tendancy of fuel oil to degrade during storage, not the actual fuel oil condition.
In addition, the accuracy of the test is ques-tionable and, finally, the ASTM D-2274 test is more commonly used as a means of quality assurance at refineries. Testing in accordance with ASTM D-2276, however, will provide important information on the actual condition of the fuel in the storage tanks.
Comparison of test results over time will provide an accurate indication of actual fuel degradation, if any, in sufficient time for corrective action and without impairing EDG operation. The staff agrees with the licensee's rationale. Testing of diesel fuel oil in accordance with ASTM D-2276 in lieu of ASTM D-2274 was initially accepted for McGuire Nuclear Station and has subsequently been accepted for use at several other plants.
In all cases, however, the ASTM D-2276 test has been just one part of a comprehensive diesel fuel. oil. surveillance pro-gram. The licensee has not included the remainder of this program in its TS change proposal. However, in response to the. staff's concerns,
the licensee provided information on their diesel fuel procurement and testing program which is implemented by procedure. This informa-tion was included as Enclosure 2 to the licensee's September 30, 1986 supplemental submittal and consists of one page entitled, " San Onofre Complete Diesel Fuel Procurement and Testing Program'.', and a copy of Chemistry Procedure 50123-III-6.6, Revision 2 entitled, " Diesel Fuel Oil Specifications and Testing Requirements." The licensee also informed the staff that the diesel fuel storage tanks and tank vaults were checked periodically for the presence of and removal of accumulated water in accordance with procedure S0(1)23-I.8.-154 entitled " Tank Inspection / Dewatering-Diesel Fuel Oil Storage Tanks and Vaults."
With the inclusion of the above additional testing and inspection, the licensee's program for diesel fuel oil surveillance is equivalent to programs the staff has previously accepted.. The licensee's proposed TS change is, therefore, acceptable on the basis that the additional diesel fuel oil testing and inspection as described above is conducted by a staff accepted procedure.
l l
+1 0
(,
3.3 4KV Safety Bus LCO The licensee has requested changes to the Action Statements in the TS to reflect the design of the SONGS 2 & 3 offsite power system which provides two offsite power sources to each 4KV safety bus. In order to adequately evaluate this proposal, the staff must first determine whether the two offsite power sources are truly independent. This will require a review of the control and protection schemes for cir--
cuit breakers which interconnect 4KV buses between Units 2 & 3.
Independent of this proposed change, the licensee has submitted.a proposal to interconnect the EDG's between Units 2 & 3.
This other proposal,NPF-10/15-215(PCN-215)involveschangestothecontrol schemes of the above bus-tie circuit breakers. In light of this, the staff feels that it would be more efficient to conduct a combined review of the breaker controls than to conduct two independent reviews. Therefore, the staff will defer review of this part of proposed change PCN-192 for the present, and include it in the staff's review of PCN-215.
4.0
SUMMARY
OF STAFF EVALUATION Based on our review of the licensee's submittals, the staff con ~cludes that a portion of the licensee's propcsal is acceptable, another portion of the proposal is not acceptable, and that staff review of the remaining part of the proposal will be deferred.
The staff finds the licensee's proposals to reduce the number of EDG fast starts and to reduce the total number of starts acceptable because they conform to the criteria in Ceneric Letter 84-15 and, as applicable, the staff position regarding Amendment 48 to the North Anna 2 TS.
The staff is deferring action on the licensee's proposals to establish an allowable cumulative inoperability limit for EDGs and to increase the LCO in TS Section 3.8.1.1 from three days to seven days pending receipt of additional analyses to support these changes.'
The staff will defer evaluation of the licensee's proposals regarding off-site power source to the 4KV safety buses for inclusion.in the evaluation i
of PCN 215.
5.0 CONTACT WITH STATE OFFICIAL The NRC staff has advised the Chief of the Radiological Health Branch, State Department of Health Services, State of California, of the proposed determination of no significant hazards consideration. No coments were received.
t...
6.0 ENVIRONMENTAL CONSIDERATION
These anendments involve changes in the installation or use of facility components located within the restricted area. The staff has determined that the amendments involve no significant increase in the amounts of any effluents that may be released offsite and that there is no significant increase in individual or cumulative occupation radiation exposure. The Comission has previously issued proposed findings that the amendments involve no significant hazards consideration, and there has been no public comment on such findings. Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth.in 10 CFR Sec.
51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need to be prepared in connection with the issuance of these amendments.
7.0 CONCLUSION
Based upon our evaluation of the proposed changes to the San Onofre Units 2 and 3 Technical Specifications, we have concluded that: there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, and 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. Ve, therefore, conclude that the proposed changes are acceptable (with the exceptions noted in Sections 3.2, and 3.3, above), and are hereby incorporated into the San Onofre 2 and 3 technical specifications.
Principal Contributors:
E. Tomlinson M. Rubin Dated: April 9,1987 l
l l
i l