ML20079P154
| ML20079P154 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 11/01/1991 |
| From: | James Fisicaro ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 2CAN119102, NUDOCS 9111120248 | |
| Download: ML20079P154 (5) | |
Text
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.Entergy
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Operations November 1, 1991 2CAN119102 U. S. Nuclear Regulatory Commission Document Control Desk Mail Station Pl-137 Washington, DC 20555
Subject:
Arkansas Nuclear Onn - Unit 2 Docket No. 50-368 biccuse No. NIT-6 Testing of Anticipated Transients Wit hout. Scram Modi ficat ions Gentlement The Anticipated Transients Without Scram (ATWS) Rulo requires improvements in the design and operat ion of commercial nuclear power facilities to reduce the likelihood of failure to shutdown the reactor following anticipated transiercs and to mitigatn the consequences of an ATWS event.
The requirements for Arkansas Nuclear One, Unit 2 ( ANO-2) were to provide a diverse scram system (DSS), diverse auxiliary feedwater system (DAFW) actuation, and diverse initiation of turbine trip (DTT).
In response to Entergy Operations' submittals dated November 3, 1988 (2CAN118801), February 2, 1989 (2CAN028904), and Februsry 21, 1989 (2CAN028906), the Staff issued a safety evaluation (SE) on July 21, 1989 (2CNA068902), addressing the acceptability of the ANO-2 DSS and DTT designs. The final ATWS requirement, DAFW or diverse emergency Icedwater actuation system (DEFAS), was described in letter 2CAN019003, dated January 15, 1990.
In letter dated May 1, 1990 (2CNA059001), the Staff issued an SE for the DEFAS design and concluded that the design was acceptabin.
As part of thn Entergy Operat. ions' submittals, thn frequency and type of testing that. would be performed on the DSS and DEFAS were described and the SEs determined this to be acceptable. During a review of the testing of the DEFAS, it was determined that the testing requirements listed in the Entergy Operations' submittals were not fully implement.ed and required more accurate reflection of the testing being performed at ANO.
In addition, it was determined that since thn DSS has a similar type of logic system, the DSS testing requirements also required clarification.
Entergy Operations bolleves that the testing currently being performed demonstrates the funct anal capability of the DSS and DEFAS.
The purpose of this letter is to clearly identify the f requency and tyne of testing being performed on the DSS and DEFAS.
9111120248 911101 0
PDR ADOCK 05000363 i
P FDR i\\
U. S. NRC November 1, 1991
' Page 2 MS Entergy Operations' letter 2CAN118801, dated November 3, 1988, addresses the testing of the DSS.
Sectlon 3.2.2.10 (Testability at Power) of the attachment to the letter states that on-line testing would be provided to allow functional testing of one selected channel at a time.
Testing of the 2/4 logic matrix and final t. rip action would be dono during a plant shutdown or prior to startup.
Section 3.2.3.3 (Surveillance Program) states that a program to perform daily channel checks, monthly functional tests and calibration at refueling intervals would be established.
The following testing requirements being applied to the DSS supercede any prey!aus testing approaches and have been incorporated into the appropriate ANO-2 testing procedures:
Daily channel checks will be performed.
At power, testing of the DSS 2/4 logic will be performed on a monthly basis with the final DSS trip devices bypassed. During this period of time, DSS will not function to trip the reactor, The battery associated with DSS will be tested every other month as e
part of the monthly at power test.
DSS functional testing will be performed in conjunction with DEFAS functional testing.
DSS functional testing will consist of the 2/4 logic test to the actuating devices.
During the functional test, the inputs to the Reactor Protection System / Engineered Safety Features Actuation System (PPS/ESTAS) cabinets will be bypassed and DSS enabled.
DF"AS will then be actuated from the Control Room pushbuttony. *; verify that the system responds. Testing of the DEFAS 2/4 logic will also be performed with the signal to the ESFAS cabinets (Auxiliary Reiny Cabinets) bypassed.
(DEFAS functional testing is the same as described in the DEFAS monthly test description below.) The DSS /DEFAS functional test will be performed prior to a reactor startup when the reactor has been shutdown for more than seven days.
DEFAS Entergy Operations' letter 2CAN019003, dated January 15, 1990, addresses the testing of the DEFAS.
Section 6.0 (Test Capabilities) states that the DEFAS cabinet testing involves testing of the 2/4 logic system which could be conducted for one channel at a time at full power.
In addition, the DEFAS testing at power would be performed on the same schedule as that is currently used for.the ESFAS. This testing (ESFAS testing), known as channel functional testing, is done on one logic channel each week on a rotating basis, designed to test all four channels every month while in Mode 1.
All four channels would be tested prior to each return to criticality after a forced or scheduled outage greater than seven days in duration.
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- 11. S. NRC November 1, 1991 page 3 l
Part 8 of Section 7.0 (Conformance to 10CFR50.62 Guidance) states the DEFAS design allows for on-line functional testing of one selected channel at a time. With one channel in test, the DEFAS becomes a 2/3 logic system.
Testing of the entire 2/4 logic would be conducted during plant shutdown or prior to startup. DEFAS testing occurs at the DEFAS Cabinet and at the Auxiliary Relay Cabinet.
The following test ing requirements bning applied to the a.FAS supercedn any v
previous testing npproaches and havn been incorporated into the appropriate ANO-2 testing procndures:
Daily channel checks will bo performed.
At power, testing will consist of the DEFAS 2/4 logic test at. the DEFAS cabinet.
Testing will be performed on a monthly basis with all channels bypassed.
During this time, DEFAS will not respond to a low Steam Generator signal.
The signal to the CSFAS cabinots (Auxiliary Rolay Cabincts) is bypassed.
It should be noted that this test does not test. the circuitry all the way to the output of the component..
A Control Room alarm provides indication of the cont.inuity of the circuitry between the DEFAS and ESFAS cabinets (the alarm annunciates if the cont.inuity is broken).
The battery associated with DEFAS will bn tested evnry other mont.h as part of the mont hly DEFAS (nst.
The DEFAS functional test will be performed as described abovo with the DSS functional test.
The channel calibrat.fon for DEFAS will be performed during refueling outages.
The procedure is currently boing developed and will be used during the next refueling outage (2R9).
These changes and clarifications establish the actual frequency and type of testing being performed on thn DSS and DEFAS for ANO-2.
Should you have any questions regarding this issue, pinasn contact me.
Very truly yours, pm -
James
. Fisicato Director, I.icensing JJF/RWC/sj f
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Ms. Sheri Peterson NRR Project Natinger, Region IV/i.No-2 U. S. Nuclear Regulatory Commission NRR Mail Stop *1-D-23 One k'hite Flir< North 11555 r
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RESPONSE
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This response is verified to be technically accura.e and complete.
Supporting documente* ion is attached / referenced.
ACTION COMPLETED BY: 7N Mud d,
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DATE:
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CODE INSPECTOR REVIEW:
I.I DATE:
(if required)
Y This rosponse prcvides adequate resolution to the action.
I have __ have not __
issued any follow-up actions:
APPROVED:
DATE:
(Assigning Manager)
POTE:
St.ould the response determine that an is inoperable, immediately cortact the Control Room.y equipment / system CONDITION RF? ORT - CORRECTIVE ACTION RESP 3NSE 1000.104F T
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