ML20211R057
| ML20211R057 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 09/09/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20211R046 | List: |
| References | |
| NUDOCS 9909160042 | |
| Download: ML20211R057 (7) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 2006H001 5.;'*****/
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO.158 TO FACILITY OPERATING LICENSE NO. NPF-10 AND AMENDMENT NO.149 TO FACILITY OPERATING LICENSE NO. NPF-15 SOUTHERN CALIFORNIA EDISON COMPANY SAN DIEGO GAS AND ELECTRIC COMPANY THE CITY OF RIVERSIDE. CAllFORNIA THE CITY OF ANAHEIM. CALIFORNIA SAN ONOFRE NUCLEAR GENERATING STATION. UNITS 2 AND 3 DOCKET NOS. 50-361 AND 50-362
1.0 INTRODUCTION
By application dated June 18,1997 (PCN-478), as supplemented May 24 and August 10,1999, Southern California Edison Company (SCE or the licensee) proposed changes to San Oncfre Nuclear Generating Station (SONGS) Units 2 and 3 Technical Specification (TS) Surveillance Requirements (SRs) related to diesel generator (DG) testing to more clearly reflect safety analysis and testing conditions as it is performed. The proposed changes would revise TS 3.8.1, SR 3.8.1.1 (Unit 3 only), 3.8.1.2, 3.8.1.7, 3.8.1.10, 3.8.1.11, 3.8.1.12, 3.8.1.13, 3.8.1.14, 3.8.1.15,3.8.1.16,3.8.1.17,3.8.1.19, and 3.8.1.20, and the associated Bases.
l On December 31,1997, the NRC noticed in the Federa/ Register (FR) the licensee's proposed l
changes and basis for proposed no significant hazards consideratior, determination (62 FR 68315). The licensee's letters dated May 24 and August 10,1999, provided updated TS pages, clarifications, and additional information that were within the scope of the original FR notice and did not change the staff's initial proposed no significant hazards consideration l
determination.
2.0
_ EVALUATION The licensee proposed the following changes to the SONGS Units 2 and 3 TSs.
2.1 The proposed revision to SR 3.8.1.1 is to indicate corrected Unit 2 cross-tie breaker numbers. The change is applicable to Unit 3 only. The licensee states that these breaker numbers were inadvertently revised in Amendment 116. The staff finds the above change to be editorial and acceptable.
9909160042 990909 PDR ADOCK 05000361 P
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, 2.2 SR 3.8.1.2 currently requires verification that each DG starts from standby conditions and achieves steady-state voltage 23924 V and s4796 V, and frequency 2 58.8 Hz (hertz) and s 61.2 Hz. The proposed change would provide the correct voltage and frequency limits for DG operability. The lower voltage limit is changed from 3924 V to 4297 V. This is the voltage that the DG must achieve to reset the 4.16 kV (kilovolt) engineered safety features (ESF) bus undervoltage relays to allow ESF load sequencing to initiate. The undervoltage relay reset is a permissive that must be satisfied to initiate the ESF load sequence timers when an ESF actuation signal is present. The upper voltage limit is changed from 4796 V to 4576 V to be consistent with the maximum allowable steady-1 state voltage for 4.16 kV motors (110% of 4160 V).
j The lower frequency limit is changed from 58.8 Hz to 59.7 Hz. The lower frequency limit is equal to -0.5% of the 60 Hz nominal frequency and is based on maintaining acceptable high pressure safety injection system performance as assumed in the accident analyses.
The staff finds the proposed voltage and frequency limits to be more conservative than the current TS limits and therefore acceptable.
Additionally, the acceptance criteria are reformatted. The steady-state voltage limits and steady-state frequency limits are now referred to as acceptance criteria 'a' and 'b',
respectively. The staff finds these changes to be editorial and acceptable.
2.3 SR 3.8.1.7 currently requires verification that each DG starts from standby conditions and achieves, in s10 seconds, voltage 23924 V and s4796 V, and frequency 258.8 Hz and s61.2 Hz. The licensee has proposed to change the timing requirement for achieving the required DG voltage and frequency limits from 10 seconds to 9.4 seconds. The proposed change would now require that the DG achieve the voltage and frequency in s 9.4 seconds. SR 3.8.1.7 is also revised to provide the correct voltage and frequency limits for EDG operability as discussed in SR 3.8.1.2 (item 2.2) above. The 9.4-second requirement ensures that the DG meets the assumptions of the design-basis loss-of-coolant accident (LOCA) analysis, i.e., the DG starts, accelerates to the required frequency and voltage, connects to the 4.16 kV ESF bus, and resets the ESF bus undervoitage relay logic within 10 seconds of a safety injection actuation signal (SlAS).
Since this surveillance starts the DG but does not close the DG output breaker, the time requirement is reduced by 0.6 second (from 10 seconds to 9.4 seconds). This ensures that sufficient time exists to subsequently close the DG output breaker and reset the undervoltage relay logic without exceeding the overall 10-second start time assumed in the analysis. The 9.4-second time requirement is more conservative than the current TS limits and is, therefore, acceptable.
In addition, the SR requires that the DG maintain steady-state voltage 24297 V and s4576 V, and frequency 259.7 Hz and s61.2 Hz. The staff informed the licensee that the proposed change does not specify the time when the DG actually achieves steady-state voltage 24297 V and s4576 V, and frequency :.59.7 Hz and s61.2 Hz. The time for a DG to reach steady-state required voltage and frequency is important to ensure that the DG meets its design basis and this time must be monitored and trended to assure that there is no degradation of the governor and the voltage regulator.
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- Subsequently,' by letter dated May 24,1999, the licensee proposed to add the following sentence to the TS Bases for SR 3.8.1.7,3.8.12, and 3.8.1.15:
in addition to the SR requirements, the time for the DG to reach steady-l state operation, unless the modified DG start method is employed, is l:
periodically monitored and is evaluated to identify degradation of L
governor and voltage regulator performance.
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The above satisfies the staff's concem and is acceptable.'
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_In addition, the acceptance criteria are reformatted. Acceptance criterion 'a'shows the l
voltage and frequency limits for the timing requirement. The steady-state voltage and l
frequency limits are now referred to as acceptance criteria 'b' and 'c', respectively. Note l-two is added to credit any unplanned events that may satisfy this SR. Ti e staff finds the above changes to be editorial and acceptable.
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2.4 ' SR 3.8.1.10 currently requires verification that each DG, when operating with design-l basis kW loading and maximum kVAR (kV amperes reactive) loading permitted during testing does not trip and voltage is maintained s5450 V during and following a load rejection of 24450 kW (kilowatt) and s4700 kW.
The licensee has proposed to revise SR 3.8.1.10 to clarify the conditions under which the DG full load rejection test is performed. The term " connected to its bus in parallel with offsite powef' is added to indicate that the test is performed with the DG connected in parallel with the grid. The reference to " design-basis kW loading" is removed; instead the required kW load range is specified in the SR as 24450 kW and s 4700 kW. The licensee states that with the specified load limits, the reference to design-basis kW loading is not necessary. The staff agrees and concludes that the change is acceptable.
The phrase " maximum kVAR loading permitted during testing" is replaced by " inductive loading that offsite power conditions permit." This is to clarify that the kVAR load on the l-DG during this test may be limited by offsite power conditions. The licensee stales that
' offsite power conditions directly affect the voltage on the ESF buses. When the DG is connected to the ESF bus in parallel with the offsite source, increasing the DG output voltage increases the DG VAR output. If the bus voltage is already high due to high grid voltage, increasing the DG VAR output may cause the bus voltage to exceed allowable limits. Similarly, these test conditions could cause an overexcitation condition to occur in the generator or exciter. The plant test procedure recognizes these limitations and contains restrictions to prevent equipment limits from being exceeded. Therefore, the SR is clarified to indicate that the test is performed under inductive load conditions that are as close to design-basis conditions as possible subject to offsite power conditions. Based on the above, the staff concludes that in order to ensure that the DG is not placed in an unsafe condition during the test, the test may be performed under inductive load conditions that are as close to design-basis conditions as possible, subject to offsite power conditions. The licensee has revised this SR to clarity the above. Therefore, the staff finds the proposed change to be acceptable.
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-4 Additionally, the acceptance criteria are reformatted. The "does not trip" requirement is now referred to as acceptance criterion 'a' and the maximum voltage limit is now referred to as acceptance criterion 'b.' The staff finds these changes to be editorial and acceptable.
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2.5 The licensee has proposed to revise SR 3.8.1.11 to clarify that, in addition to the DG connecting to the ESF bus and energizing the permanently connected loads, DG voltage must also be high enough to reset the 4.16 kV bus undervoltage relay logic within
~10 seconds. This ensures that the DG meets assumptions of the design-basis LOCA analysis, which assumes that the DG starts, accelerates to the required frequency and voltage, connects to the 4.16 kV ESF bus, and resets the ESF bus undervoltage relay
- logic within 10 seconds of an SIAS. Undervoltage relay logic reset is a permissive that
- must be satisfied to initiate the ESF load sequence timers when an SIAS is present.
Additionally, acceptance criteria c.2 and c.3 are revised to provide the correct voltage and frequency limits for steady-state operation as discussed in SR 3.8.1.2 (item 2.2) above.
The staff finds the above changes to be more conservative than current TS requirements and, therefore, acceptable.
2.6 SR 3.8.1.12 currently requires verification that on an actual or simulated ESF actuation signal each DG auto-starts from standby condition and achieves, in s10 seconds, voltage i
23924 V and s4796 V, and frequency 258.8 Hz and s61.2 Hz. The licensee has proposed to revise the SR to clarify that the ESF signal that initiates a DG start is an SIAS signal. This change eliminates the ambiguity that exists in the existing SR by referring to a specific signal (SIAS) rather than ESF actuation signal. The staff finds the proposed change to be editorial and acceptable.
The licensee has also proposed to revise SR 3.8.1.12 to change the timing requirement i
for achieving the required DG voltage and frequency from 10 seconds to 9.4 seconds.
This_SR is also revised to provide the correct voltage and frequency limits for DG operability. The proposed change now would require that the DG achieves in
. s9.4 seconds the voltage 24297 V and frequency 259.7 Hz. The DG maintains steady-state voltage 24297 V and s4576 V, and frequency 259.7 Hz and s61.2 Hz. The l
l proposed changes are acceptable as discussed in SR 3.8.1.7 and SR 3.8.1.2 (items 2.2 and 2.3) above.
Additionally, the acceptance criteria are reformatted. The acceptance criterion 'a'shows the voltage and frequency limits for the timing requirement and steady-state voltage and frequency limits are now referred to as criteria 'b' and 'c', respectively. The requirement
- to operate for greater than or equal to 5 minutes is now referred to as acceptance criterion 'd'. The staff finds the above changes to be editorial and acceptable.
2.7. SR 3.8.1.13 currently requires verification that each DG automatic trip is bypassed on
- actual or simulated loss of voltage signal on the emergency bus concurrent with an actual or simulated ESF actuation signal.
.' The licensee has proposed to revise SR 3.8.1.13 to eliminate reference to the " loss of
. voltage signal" (LOVS). This change would allow the non-critical trip feature to be tested under SIAS conditions only. The licensee states that the DG non-critical trips are
' bypassed by an SIAS signal, but are not affected by the presence or absence of LOVS.
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- Under postulated SIAS LOVS conditions, the DG starts and connects to the 4.16 kV ESF bus.. The ESF bus voltage will increase to and remain above the reset voltage of the LOVS relays. The LOVS relays will reset. The non-critical trips will remain bypassed due to the SlAS. Since the LOVS has no affect on the bypassing of the non-critical trips, testing only the bypassing of non-critical trips under SIAS condition provides a valid test of the non-critical trip bypass feature. The staff agrees and concludes the change is acceptable.
This SR is also revised to clarify that the ESF actuation signal that bypasses the non-critical trips is an SIAS. This change eliminates the ambiguity that exists in the existing SR by referring to a specific signal rather than a general term (ESF actuation signal).
I The staff finds that this proposed change simply clarifies the signal that actually bypasses the non-critical trips during this SR, and therefore the proposed change is acceptable.
2.8 SR 3.8.1.14 currently requires verification that each DG operating with the maximum kVAR loading permitted during testing operates for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in SR 3.8.1.14, the phrase
" maximum kVAR loading permitted during testing"is revised to clarify that the kVAR load on the DG during this test may be limited by offsite conditions. The wording " maximum kVAR"is replaced by " inductive loading." The staff finds the above change to be acceptable as discussed in SR 3.8.1.10 (item 2.4) above.
In Note 1, the reference to power factor is removed because the power factor is no longer mentioned in this SR. For Unit 3, SR 3.8.1.14 is also revised to delete a note that is no longer applicable. The staff finds the above changes to be editorial and acceptable.
2.9 SR 3.8.1.15 currently requires that this SR be performed within 5 minutes of shutting down the DG after the DG has operated 2 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> loaded 24450 kW and s 4700 kW and verify that each DG starts and achieves, in s10 seconds, voltage 23924 V and s 4796 V, and frequency 258.8 Hz and s61.2 Hz. The licensee has proposed to change the timing requirement for achieving the required DG voltage and frequency from 10 seconds to 9.4 seconds. SR 3.8.1.15 is also revised to provide the correct voltage and frequency limits for DG operability as discussed in SR 3.8.1.2 above (item 2.2). The proposed change would now require that the'DG achieve in 59.4 seconds the voltage 24297 V and frequency 259.7 Hz. The DG maintains steady-state voltage 24297 V and s4576 V, and frequency 2,59.7 Hz and s61.2 Hz. The staff finds the proposed changes to be acceptable as discussed in SR 3.8.1.7 (item 2.2) above.
l Additionally, in Note 1, the term "outside of load range...." is revised to "outside the load change...."
For Unit 3, SR 3.8.1.15 is revi3ed to delete a note that is no longer applicable.
The acceptance criteria are also reformatted. Acceptance criterion 'a'shows the voltage and frequency limits for the timing requirements and steady-state voltage and frequency limits are now referred to as acceptance criteria 'b' and 'c', respectively. The requirement to operate for greater than or equal to 5 minutes is now referred to as acceptance criterion 'd'.
The staff finds these changes to be editorial and acceptable, j
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. 2.10 SR 3.8.1.16 is revised to indicate that the DG is manually synchronized with the offsite power source during this test. In acceptance criterion 'c', the term " ready to-load operation"is clarified to be consistence with the definition provided in the Bases for this SR. The staff finds that the above changes simply clarify the intent of the SR and are acceptable.
Additionally, the licensee has proposed to add steady-state voltage and frequency limits as acceptance criteria 'c.1' and 'c.2'. The requirement for the DG breaker to be open is also added as acceptance criterion 'c.3'. The staff finds the proposed changes to be conservative and acceptable.
2.11 SR 3.8.1.17 is revised to indicate that the test is performed with the DG connected in parallel with the grid. This SR is also revised to clarify that the ESF actuation signal that overrides the test mode is an SIAS. This change eliminates the ambiguity that exists in the existing SR by referring to SIAS rather than a general term (ESF actuation signal).
Acceptance criterion 'a' is revised to clarity the term " ready to load operation." This change is consistent with the definition provided in the Bases for this SR.
The staff finds that the above changes simply clarify the intent of the SR and are acceptable.
Additionally, the steady-state voltage and frequency limits are added as acceptance criteria 'a.1' and 'a.2'. The requirement for the DG breaker to be open is added as acceptance criterion 'a.3'. The staff finds the proposed changes to be conservative and acceptable.
2.12. SR 3.8.1.19c.1 is revised to clarify that, in addition to the DG connecting to the ESF bus and energizing the permar'ently connected loads, DG voltage must be high enough to reset the 4.16 kV bus undervoltage relay logic within 10 seconds. This ensures that the DG meets the assumptions of the design-basis LOCA analyses which assume that the DG starts, accelerates to the required frequency and voltage, connects to the 4.16 kV ESF bus, and resets the ESF bus undervoltage relay logic within 10 seconds of an SIAS.
Undc; voltage relay logic reset is a permissive that must be satisfied to initiate the ESF load sequence timers when an SlAS is present. The staff finds the proposed change to be conservative and therefore acceptable.
Additionally, the acceptance criteria 'c.3' and 'c.4' are revised to provide the correct voltage and frequency limits for steady-state operation. These changes are acceptable as discussed in SR 3.8.1.2 (item 2.2) above.
2.13 SR 3.8.1.20 currently requires verification that when started simultaneously from standby conditions, each DG achieves, in s10 seconds, voltage 23924 V and s4796 V, and frequency 258.8 Hz and s61.2 Hz. The licensee has proposed to change the timing requirement for achieving the required voltage and frequency limits from 10 seconds to 9.4 seconds. SR 3.8.1.20 is also revised to provide the correct voltage and frequency limits for DG operability as diccussed in SR 3.8.1.2 (item 2.2) above. The proposed change would new require that the DG achieve in s9.4 seconds the voltage 24297 V and
. frequency 259.7 Hz. The DG maintains steady-state voltage 24297 V and s4576 V, and frequency 259.7 Hz and s61.2 Hz. The proposed change is acceptable as discussed in SR 3.8.1.7 (item 2.3) above.
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. Additionally, the acceptance criteria are reformatted. Acceptance criterion 'a'shows the voltage and frequency limits for the timing requirement and the steady-state voltage and frequency limits are now referred to as criterion 'b' and 'c', respectively. The staff finds the proposed change to be editorial and acceptable.
l 3.0
SUMMARY
The staff concludes that the proposed changes to SONGS Units 2 and 3 TS 3.8.1, "AC Sources-Operating," SRs 3.8.1,1 (Unit 3 only), 3.8.1.2, 3.8.1.7, 3.8.1.10, 3.8.1.11, 3.8.1.12, 3.8.1.13,3.8.1.14,3.8.1.15,3.8.1.16,3.8.1.17,3.8.1.19, and 3.8.1.20 and the associated Bases are acceptable.
i 4.0 - STATE CONSULTATION in accordance with the Commission's regulations, the California State official was notified of the proposed issuance of the amendments. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendments change surveillance requirements. The NRC staff has determined that the amendments 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 radiation exposure. The Commission has previously issued a proposed finding that the amendments involve no significant hazards consideration, i
and there has been no public comment on such finding (62 FR 68315). Accordingly, the amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR i
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 the amendments.
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6.0 CONCLUSION
The Commission has 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, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributors: Ohm Chopra, NRR Date: September 9,1999 1
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