ML20085E052
| ML20085E052 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 10/09/1991 |
| From: | Cottle W ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GNRO-91-00171, GNRO-91-171, NUDOCS 9110180011 | |
| Download: ML20085E052 (6) | |
Text
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ENTERGY F"'E"
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W.1. Cottle October 9, 1991 U.S. Nuclear Regulatory Commission Mail Station P1-137 Warhington, D.C.
20555 Attontlon Document Control Deck
Subject:
Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 1.icense No. NIT-29 Response to Requent for Additional Informatiron on Relocation of Battery 1.oad P:of11e Requirernents (PCol-90/11)
CNRO-91/00171 Centlemen:
hy letters dated January 28, 1991 and August 7 1991 the staff requested additional information in ordei to complete its icview of our proposed change to the Grand Gulf Nuclear Station (GGNS) Operating Licenso dated January 11, 1990 (GNRO-91/0004). GGNS provided its response to the NRC's request dated January 28, 1991 in GNRO-91/00041.
This letter provides GGNS's response to the NRC's request for additional information dated August 'i, 1991.
Yours truly, wo VCoccz~,.
WTC/BSF/ams attachment:
cc:
(See Next Pago)
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October 9, 1991 GNRO 'il/00171 Page 2 of 3 c c. :
Mr. D. C. Illut z (wf a)
Mr. J.
1.. Hathis (w/n)
Mr. R. 11 McGehee (w/n)
Mr. N. S. Reynolds (w/a)
Mr. 11. l.. Thomon (w/o)
Mr. Stewart D. Ebneter (w/n)
Regionni Administrator U.S. Nuclear Regulatory Commission Region 11 101 Marietta St., N.W.,
Suite 2900 Atlanta, Georgia 30323 Mr. P. W. O'Connor, Project Hannger (w/a)
Offico of Nuclear Reactor Regulation U.S. Nucient Reguletory Commission Hall Stop 13113 Washington, D.C.
20555 Dr. Alton !;. Cobb (w/a)
Stat o llen11.h Of ficer Stato lionrd of lienith P.O. Ilox 170v Jackson, Mississippi 39205 l
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Attachment to GNRO-91/00171 Page 1 of 4 QUEST 10N,_1 In light of the GGNS Engineering Cniculations EC-Q1L21-90020 and EC-Q1L21-90023, piovido a description of the Division 111 battery servico t.es t, including the minimum acceptablo battery terminni voltage, which will demonst.rnto the capability of t he battery to satisfy the design requirements (battery duty cycle) of the de system. Sluco the proposed TS changes would transfer both the load prof flo and the minimum voltage for the battery service test from the TS to the FSAR, describe how the minimum acceptable voltagn for tho inst will bo specified in tha FSAR.
RESPONSE _TO_ QUEST 1.ON_1 The bat.tery service test is n special test of the battery's ability to satisfy the design requirements (battery duty cycin) of thn DC System.
The antvice test is performed by ensuring thnt the battery has sufficient capacity to supply and maintain in an OPERAllLE status the actual emergency londs or by ensuring that the battery can supply a dummy load greatnr than the actuni emergancy lond.
This dummy lond profilo encompasses the actuni emergency londs.
The dummy load profile applies consor stive nasumptions, such as assuming that londs which occur at random occur during the most critient timo during thn dnty cycin, to ensure the dummy lond prof 11e encompasses tho intgest possible lond requirement during each timo segment of thn lond prof 11c.
Supplying this connoivative dummy lond profilo results in a much more severn test of the battery's capability than supplying the actuni emergency loads. The acceptanen critnrin for thn service test when performed using actuni emergency lands is to maintain the londs in an OPERABLE status during the test duration.
The acceptance criterin for the service test when performed with a dummy lond is currently specffleu to be 105 V dc in the Technien1 Specifications (the battery sizint voltage limit).
Following the impicmentation of this proposed change to the Technlen1 Specifications the lond proflin of the dummy lond r.nd the accept enco criterin of tho service test using the dummy load will be controlled by the Updated Final Safety Analysis Report (UFSAR).
The emergency lond profila is developnd in eniculation EC-Q1121-90020, for Division III. In accordance with IEEE Standard 485-1978 Recommended Practice for Sizing Largo Storngo Bat.torins for Generating Stations and Substations.
Thn prof fic of the dummy lond used in the service test encompasses the actual emergency lond prof 11o.
Following this license amendment, the profile of tho dumny lond used in the servien test will be contained in the UFSAR.
Cniculat ion EC-Q1L21-90023 appl.ics the vendor supplied battery specifle performanco charactoristics, for the battery load profilo devnloped in accordance with IEEE 485, and assures that cach component. will perform its function under the design bases conditions. Tho neceptance criterin for the service test will ensure that the minimum battery terminni voltage does not decrease below thn voltages deternined to be acceptable by cniculation.
Following thin ifcenso amendusnt, 'hn minimum acceptabic terminni voltages during the lond profile test will on cont ained in the UFSAR.
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Attachment to GNRO 91/00171 Page 2 of 4 QUESTIM_2 In light of 1.ER 9-012-01 (sic, l.ER 90-012-01), describe how the UFSAR l
will be-revised to reflect the actual calculated minimum voltages of the Division III 125 volt de system.
Include a description of components, if any, which will be testod at calculated minimum voltages which are below the manufactures' recommended minimum voltagen for those components.
Include a deccription of the tests in suf ficient detail to show that the test conditions will be at least equivalent to the adverso conditions used in the manufactures' qualification tests.
Describe how operation at lower voltagas will af fect design lifetime and replacement beforo predicted failure.
RESPONSE _T0_ QUESTION _2 The UFSAR Section 8.3.2.1.7 contains the description of the Division III DC System.
(Note: There are several references to Division III (or C flattery) in other subsections of 8.3.2.1.
These references are only to indicato applicablo load tables, required independence between divisions, and provido descriptions of support equipment. and structures.) The UFSAR description of the Division III 125 V DC System does not require revision as a result of LER 90-012-01.
There are no required components'in the Division 211 125 V DC System that require testing at voltages below the manufacturers recommended minimum voltages.-
QUESTION 3 In light of the GGNS Engincoring Calculations for Divisions I nnd II 125 volt de systems to be provided in response to our June 21, 1991, letter, provido the same type of information for these divisions as requested in the above two requests for Division III.
RESPONSE TO QUESTION 3 Details 'of the GGNS Engineering Calculatlons for the Division I and Division II 125 V DC System comparable to the dntails provided for Division III have not. been attached to this letter duo to their extremo length, approximately 5 3-inch bindors.
These calculations have been provided to the GGNS Rosident Inspector.
Information portaining to Divisions I and II as requested in the above two gunstions for Division III is provided below:
- 1) The Response to Quostion 1 abovo with the approprint.o calculation numbers substituted also applies to Divisions I and II.
2). The UFSAR describes the 125 V DC System (excluding Divjsjon III as discussod-in thn Responso to Question 2) in Section 8.3.2.1.
This l
description states that the voltago design limit (for sining) is 1.75 V de per coll. This limit is consistent with the value used for the Division I and Division II sizing calculations.
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At.tachment to GNRO-91/00171 Page 3 of 4 e
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This description also states that the voltage at the safety related i
DC buses is designed to be maintained within the limits of 105 V de to 140 V de during all plant modos, including accident conditions.
105 V de corresponds to sixty (60) series cells, at 1.75 V por cell (the design limit dictated by battery sir.ing paramotors). While the 10$ V de limit at the DC bus does not account for the voltago drop between the battery and the bus, this drop in loss than 1.0 V dc
.during worst caso design loading conditions. The UFSAR will be modiflod to show that the DC System voltage is designed to romain betwoon the 105 V de to 140 V de at the battery terminals instead of at the DC bus.
The UFSAR also will bo modified to show that the actual voltages at the individual components will be lower than the batteries' volingo due to circuit voltage drop.
The UFSAR states that all direct curro*t equipment is specified for operation over the range of 105 V de to 140 V dc.
Review of components associated with LER 90-012-01 has determined that most of the components moot or exceed this UFSAR statomont. All of the components that do not moot this UFSAR requirement woro determined to
.rocolve the manufacturor's minimum rated voltage except the trip coil for the Reactor Coro isolation Cooling (RCIC) system trip and throttle valvo.. This component was found to be acceptablo por the tert program described below.
The UFSAk will.be revised to reflect that components that can not moet the DC System specified operation rango will be ovaluated on a case by case basis.
Certain Division I and Division 11 components worn datormined to be required._to operato at voltages below the manufacturer's stated minimum voltago. All the components' identified.woro olectromechanient devices such as switchgear spring charging motors, switchgear closo coils. Motor Operated Valvo 'contactors, or solenoids.
Testing of those components wau performod as follows:
A.
The actual component minimum voltage' requirement was established by using a variablo DC voltage source to determine the devico
. minimum operating voltago. All devices tested woro electromechanical dovices and woro visually veriflod to perform their function on a repeatable basis at the actual minimum voltage.
B.
The actual component minimum voltage requiremont determined by testing was verified.to provido at least a 10% margin between it and the calculated minimum voltago.
The testing will-be performed ovory la months. No significant devico t
characteristics changes are expected to occur within this interval.
The UFSAR will be modified to show that unless qualified by field testing', all components'will be qualiflod by the manufacturer for the calculatri limiting voltage supplied to the equipment.
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o Attachment to GNRO-91/00171 Pago 4 of 4 The testing performed provides adequata assuranco that these components will perform their requirod functions. For the following reasons device qualification is not invalidated or the design lifetimes reduced by the use of these devices at. lower than manufacturor's stated voltage:
A.
All of the tested devices are intormittently onergized for very hrlof periods to perform their design funct fon. Thoroforo, effects such as mechanical wear or thermal aging associated with device energization will bo insignificant.
B.
All of the tested devices woro procured in accordance with IEEE 323-1974. Therefore, the devices aro qualified for the service conditfons to which the devices could he exposod.
Since the only electrically induced failuro modo for thoso oloctromechanical devices is insulation failuro (coil winding conductors and device cores are metallic and, as a result, not susceptibio to radiation or thermal aging) the dnvico qualification needs specific review only to insure that reduced voltago does not. Increase the degradation rato for which the device was-qualified. As previously stated, all of the devices are intermittently ennrgized, and as such, degradation beyond device qualification bounds is not postulated.
C.
Device performance variation due to conductor temperature offects for the tested devices is not significant.
This is due to the relatively low resistance temperature coefficient for copper in conjunction with the t estod devices being located in
. areas where temperature swings arn accounted for by the available matgins (e.g., Switchgoar Rooms, RCIC Pump Room, and Standby Service Water 11asin).
Due to the nature of the devicca affected (all electromechanical and procured in-accordance to IEEE 323-1974) and the margin betwocn the actual' minimum devico operation-voltage and the calculated minimum voltage, this testing prov. ides adequato assuranco of the proper operation of.this equipment during a Design Basis Accident.
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