ML20058F666
| ML20058F666 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 11/24/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20058F631 | List: |
| References | |
| NUDOCS 9312080221 | |
| Download: ML20058F666 (3) | |
Text
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t UNITED STATES i
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NUCLEAR REGULATORY COMMISSION 5'
WASHINGTON, D.C. 205554 001
- o ENCLOSURE SUPPLEMENTAL SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTCR REGULATION ALTERNATE AC SOURCE - STATION BLACK 0UT MODIFICATIONS ENTERGY OPERATIONS. INC.
ARKANSAS NUCLEAR ONE (ANO). UNITS 1 AND 2 DOCKET NOS. 50-313 AND 50-368
1.0 INTRODUCTION
The NRC staff's Safety Evaluation (SE) and Supplemental Safety Evaluation (SSE) pertaining to Entergy Operations' (the licensee's) responses to the Station Blackout (SBO) Rule, 10 CFR 50.63, were transmitted to the licensee by letters dated October 10, 1990, and October 24, 1991, respectively. The staff's SSE accepted the licensee's proposed use of a new diesel generator as an alternate AC (AAC) power source for coping with an SB0 subject to confirmation that the AAC source would have the capacity and capability to power the Class IE battery charger (s) and the necessary reactor coolant inventory equipment. The licensee confirmed these two items by [[letter::0CAN119107, Forwards Comments on AEOD Special Rept, Experience W/Pump Seals Installed in Reactor Coolant Pumps Mfg by Byron Jackson & Responses to Questions Re Proposed Resolution of GSI 23.W/o Comments on Resolution of GSI 23|letter dated November 26, 1991]].
Subsequently, although not required or requested by the staff, the licensee voluntarily submitted the conceptual design of the SB0 modifications for staff review, by letter dated August 14, 1992.
The staff's SE pertaining to the licensee's conceptual design of the SB0 modifications was transmitted to the licensee by letter dated December 18, 1992. The staff's SE found the proposed ANO AAC conceptual design using a new non-safety-related diesel generator to be acceptable based on its meeting the guidelines of Regulatory Guide 1.155 and NUMARC 87-00, and also accepted the licensee's proposed schedule of.
December 31, 1994, for implementing the SB0 Rule. The SE also requested that the licensee commit to an initial test of the AAC power source in accordance with Part B.12 of NUMARC 87-00. The licensee responded to the staff's SE by letter dated February 26, 1993, and confirmed its intent to conduct the one-time diesel test in the subsequent AND-1 and ANO-2 outages after the December 31, 1994, implementation date.
As a result of conversations between the NRC staff and the licensee regarding the testing of the new diesel generator, the licensee provided information by [[letter::0CAN069302, Informs That Per SBO Rule 10CFR50.63,util Committed to Install New Onsite Power Source Separate from ANO safety- Related EDGs & Vital Batteries.Listing of ANO SBO Diesel Tests Encl|letter dated June 29, 1993]].
Subsequently, in response to further questions from the staff, the licensee provided additional information on September 17, 1993.
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i 2.0 DISCUSSION By letter dated February 26, 1993, the licensee confirmed its intent to conduct the one-time diesel test in accordance with Part B.12 of NUMARC 87-00.
The licensee stated that the AND AAC conceptual design submittal of August 14, 1992, reiterated many of the design and testing requirements committed to in the earlier ANO letter of April 15, 1991. The commitment of Part B.12 was, however, only contained in the former submittal of April 15, 1991. The licensee previously indicated that this one-time test will be conducted in the subsequent ANO-1 and ANO-2 outages after the December 31, 1994, implementation f
date, currently expected to commence in the spring and fall of 1995.
The licensee did not believe the B.12 test to be an exception to the December 31, 1994, implementation schedule. The licensee indicated that the non-safety-related diesel generator will be available for responding to an SB0 l
by the committed schedule, and the one-time test is considered to be a confirmatory functional test of the AAC power source. The licensee further stated that prior to the acceptance of the AAC power source by December 31, 1994, ANO will confirm the operability of the generator set, the generator capacity, the ability of the AAC power source to carry rated electrical loads and the design function of the diesel's support systems.
The licensee provided details of the factory testing, ANO acceptance testing, operational testing to be conducted in 1994, and NUMARC 87-00 Rev. 1 initial test (B.12) and design load test to be conducted at the first outage on each unit (1995).
The design load test demonstrates the ability of the generator and excitation system to accept the most severe electrical load without experiencing instability resulting in generator voltage collapse, or evidence of the inability of the voltage to recover. During a telephone conversation with the NRC staff on March 29, 1993, the licensee stated that due to the delivery schedule of the AAC diesel generator, the licensee will be unable to perform i
the initial test (B.12) before the December 31, 1994, implementation date, since this test cannot be performed during plant operation (this constraint is i
implied in the February 26 and [[letter::0CAN069302, Informs That Per SBO Rule 10CFR50.63,util Committed to Install New Onsite Power Source Separate from ANO safety- Related EDGs & Vital Batteries.Listing of ANO SBO Diesel Tests Encl|June 29, 1993, letter]]s even though it is not specifically stated),
t In response to the staff's questions, the licensee provided the following information on September 17, 1993. The declaration of an SB0 will typically l
occur around the 10-minute point depending upon the symptoms being displayed.
The licensee indicated that it is expected to take 15 to 20 minutes to declare an SB0 as a worst case. The licensee further indicated that for the initial test to be successful, the voltage on the selected safety bus shall be greater than 4000 volts, and frequency shall be greater than 59 Hz and less than 61 Hz.
3.0 EVALUATION i
Based on its review, the staff finds that the licensee will not be in complete compliance of the SB0 Rule by December 31, 1994, since the AAC power source 1
will not be demonstrated by initial test (B.12) to be capable of powering i
required shutdown equipment within 10 minutes. However, the licensee stated
i,
that the factory testing will include an engine performance test and a generator set performance test (including load acceptance, load stability, step load acceptance and rejection, and load duty cycle tests).
In addition, l
the licensee will perform pre-operational tests comprising auxiliary system i
testing (starting air, fuel oil transfer, exhaust and air intake, building heating, ventilation, and air conditioning (HVAC) and radiator performance, and electrical system) and engine generator starting and design load rejection tests.
The licensee further stated that a performance test will be conducted in 1994, to confirm the ability of the generator set to carry load equal to its standby, prime power, and continuous ratings for both short and long periods of time.
This test is conducted as follows. The machine is started, loaded to 50%, and allowed to reach stable operating temperatures. The load is then increased to 110% and maintained for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The load is then reduced to 100% and operated for 22 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />. The engine is then unloaded and stopped.
Within 5 minutes the engine is restarted and loaded to its standby rating (120%). This load is held for approximately 15 minutes, the machine is then unloaded slowly allowing temperatures to stabilize before the machine is stopped. This test also confirms the operability of the integrated system components.
The staff agrees that the above tests are adequate to demonstrate operability of the AAC diesel generator. The staff accepts the acceptance criteria for the initial test and the time required (typically around 10 minutes and worst case 15 to 20 minutes) to declare an SBO. Therefore, the staff acctats the licensee's position of conducting the initial test (B.12) and design load test r
in the spring and fall of 1995 and considers this issue to be resolved.
4.0 CONCLUSION
The staff has reviewed the licensee's commitment of performing the initial test (B.12) in the spring and fall of 1995 due to the delivery schedule of the i
AAC diesel generator.
Based on our review of the factory testing and AND acceptance testing and operational testing to be conducted in 1994, the staff i
agrees with the licensee that the non-safety-related AAC diesel generator will be available for responding to an SB0 event. The staff accepts the licensee's position of conducting the initial test (B.12) and the design load test in the spring and fall outages of 1995 and considers the SSE issue to be resolved.
Principal Contributor:
A. 8 Pal, EELB Date: November 24, 1993 l
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