ML20203B476

Summary of 980128 Meeting W/Util in Rockville,Md Re Licensee Application for License Amend .List of Attendees & Licensee Response to Questions Encl

ML20203B476
Person / Time
Site:	Vogtle
Issue date:	02/11/1998
From:	Jaffe D NRC (Affiliation Not Assigned)
To:	NRC (Affiliation Not Assigned)
References
NUDOCS 9802240298
Download: ML20203B476 (12)

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'2 NUCLEAR REGULATORY COMMISSION UNITED STATES WASHINGTON, D.C. 2006Ho01

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• February 11, 1998 LICENSEE: Southem Nuclear Oper. ting Company (SNC)

FACILITY: Vogtle Electric Generating Plant, Units 1 and 2

SUBJECT:

THE NOVEMBER 20,1997, APPLICATION, TO CHANGE THE TECHNICAL SPECIFICATIONS (TS) RELATED TO THE REACTOR TRIP SYSTEM (RTS AND ENGINEERED SAFETY FEATURE (ESF) TRIP SETPOINTS On January 28,1998, representatives of SNC and the NRC staff met in Room O-10 B13, of the One White Flint North Building, Rockville, Maryland. The purpose of the meeting was to discuss SNC's application for licence amendment dated November 20,1997. Enclosure 1 contains a list of attendees. Prior to the meeting, SNC had been provided with a list of questions, by the NRC staff, that would be discussed at the meeting. The questions and SNC's responses are contained in Enclosure 2. Since the NRC staff representative from the Reactor Systems Branch (SRXB) was not in attendance, it was decided to discuss the SRXB questions at a later date.

SNC and the NRC staff discussed SNC's proposal to remove the inequality signs from the trip setpoints in the TS tables that contain the RTS and ESF Trip Setpoints. SNC indicated that the inequality signs require the RTS and ESF be to set conservatively but do not recognize that the setpoints may be above, or below, the stated Trip Setpoint due to normal setpoint " drift." The subject TS tables currently contain two columns which are " Allowable Value" and " Trip Setpoint" values. SNC proposes to remove the inequality signs from the " Trip Setpoint" values and rename this column

• Nominal Trip Setpoint." The NRC staff indicated that, while they i

agreed with the removal of the inequality signs, there was no general agreement on how to restate the values for the Trip Setpoints. The NRC staff indicated that this problem was

" generic" to those facilities with the Improved Standard Technical Specifications and had not been resolved, to the satisfaction of ths NRC staff, for any facility. For this reason, there was no suitable "model" for resciution. SNC indicated thei trere was no consensus for resolution o this problem within the Westinghouse Owners Group. In discussing the setpoint methodology, SNC !ndicated that the methodology was actually contained in a number of documents and that there was a need to compile these documents into a definitive list of references.

The NRC staff indicated that one acceptable solution to the Trip Setpoint TS table problem was to develop a proposed TS with two columns, each containing Limiting Safety System Settings (LSSS), which would bound a given trip value. Each column would have a TS Action Statement providing the remedial action that would be taken should the "as found" setpoint value be noriconservative. After discussion of SNC's responses to NRC staff questions, the meeting d.b bT i,.sr T"W O LDaud LN]

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was suspended so that SHC personnel could caucus. Follnwing resumption of the meeting, SNC Indicated that it would develop the NRC suggestion of a TS table, with two columns of LSSS settings and associated Action Statements. The proposal would be discussed with the NRC staff prior to fonaal submittal,  ;

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David H. affe, en or Project Manager 3

Project Directorate ll.2 i

' Division of Reactor Projects .1/il Office of Nuclear Reactor Regulation Docket Nos. 50-424 and 50-425

Enclosures:

1, List of Attendees

} 2. NRC Staff Questions and SNC's Responses i

cc w/encis: See next page e

2 February 11, 1998 was suspended so that SNC personnel could caucus. Following resumption of the meeting, SNC Indicated that it would develop the NRC ruggestion of a TS table, with two columns of i LSSS settings and associated Action Statements. The proposal would be discussed with the NRC staff prior to formal submittal.

CRIGINAl. SIGNED BY: '

David H. Jaffe, Senior Project Manager Project Directorate 112 Division of Reactor Projects . l/II Office of Nuclear Reactor Regulation l Docket Nos. 50-424 and 50-425

Enclosures:

1. List of Attendees

2. NRC Staff Questions and SNC's Responses cc w/encts: See next page Distribution w/ encl.1 only Distribution w/encls.1 & 2 E Mail < Osehet Mlef SCollins/FMiraglia CDoutt PUBLIC BBoger JMauck PD 112 Rdg.

JZwolinski CSchulten OGC HBerkow BMcCabe ACRS DJaffe MTschiltz LBerry  ! Johnson, Rll TMartin (e-mail SLM3) PSkinner, Ril To receive a copy of this document, Indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with attachment / enclosure "N" = No co >y OFFICE PM:PDI(2Q ) LA:PDil al[ D:P,qty 2m l NAME DJaffeM/ // LBerry X(\ ) HBer$w DATE 3/l/ /98 '

4/)U/98 \ 'l/11/38' / /98 / /98 / /97 DOCUMENT N'AME:G:\VOGTLE\MTG. SUM OFFICIAL RECORD COPY

Vogtle Electric Generating Plant I cc:

Mr. J. A. Bailey Harold Rel.<ls, Director Manager, Licensing Department of Natural Resources Southem Nuclear Operating 205 Butler Street, SE. Suite 1252 Company, Inc. Atlanta, Georgia 30334 P. O. Box 1295 .

Birmingham, Alabama 352011295 Attort,sy General Law Department {

Mr. J. B. Beasley 132 Judicial Building General Manager, Vogtle Electric Atlanta, Georgia 30334 Generating Plant Southem Nuclear Operating Mr. R. D. Barker Compar,y, Inc. Program Manager P. O. Box 1600 Fossil & Nuclear Operations Waynesboro, Georgia 30830 Oglethorpe Power Corporation 2100 East Exchange Place Regional Mministrator, Region ll P. O. Box 1349 U. S. Nuclear Regulatory Commission Tucker, Georgia 300851349 Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Charles A. Patrizia, Esquire Atlanta, Georgia 30303 Paul, Hastings, Janofsky & Walker 12th Floor Office of Planning and Budget 1050 Connecticut Avenue, NW.

Room 615B Washington, DC 20036 270 Washin,qton Street, SW.

Atlanta, Georgia 30334 Arthur H. Domby, Esquire Troutman Fanders Office of the County Commissioner NationsBank Plaza Burke County Commission 600 Peachtree Street, NE.

Waynes1;oro, Georgia 30830 Suite 5200 Atlanta, Georgia 30308 2216 Mr. J. O Woodard Executive Vice President Resident inspector Southem Nuclear Operating U. S. Nuclear Regulatory Commission Company, Inc. 8805 River Road P. O. Box 1295 Waynesboro, Georgia 30830 Birmingham, Alabama 35201-1205 Steven M. Jackson Mr. C. K. McCoy Senior Engineer Power Supply Vice President Municipal Electne Authority Southem Nuclear Operating of Georgia Company, Inc. 1470 Riveredge Parkway, NW P. O. Box 1295 Atlanta, Georgia 30328-4684 Birmingham, Alabama 35201

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LIST OF ATTENDEES N6ME ORGANIZATION  !

C. Doutt NRC D. Jaffe NRC  :

J. Mauck NRC -

C. Schulten NRC J. Bailey SNC '

L. Smith SNC N. Stringfellow SNC  :

L Ward SNC C. Tuley Westinghouse E

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4 4 Enclosure 1 4

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Agenda ltems for January 28 Setpoint Meeting 1.

Discuss footnote to Tables 3.3.1 1 and 3.3.2 1 that allows trip setpoints to be set more conservative based LCOs.

on plant conditions. Discuss why footnote is not assigned to particular functional units or De footnote was deliberately written to be a global note. It was never intended to be limited to particular functional units or LCOs.

With the inequalities applied to the trip setpoints in the current TS, we have the latitude one or all trip setpoints more conservative today.

ne latitude to set trip setroints more conservative than the TS value is not in conalet with the setpoint toethodology.

We need the Dexibility for more thanjust the speelfic TS requirements that call for a reduction in

! the power range neutron flux high or overpower delta T trip setpoint (parameter K4). [LCO 3.2.1, Required Actions A.I and A.3 (111 Flux and OPDT); LCO 3.2.2, Required Action A.l.2.2 (Ill Flux); LCO 3.7.1, Required Action A.2 (111 Flux))

For exarnple, during startup, the power range neutron Dux high trip setpoint is set consen low at several levels to facilitate stanup until a suf0clently high power level is reached to allow a good calibration. It is not appropriate to facilitate this process by putting a time limit on meeting the applicable surveillance requirement, nis forces the startup schedule to meet the surveillance requirement time limit instead of allowing the startup to proceed as require by providing the flexibility to set the trip serpoint more conservative than required by the T Another example for consideration is the reactor coolant low Dow trip setpoint. He current TS value is greater than or equal to 90 %. De Bases state that the setpoint is in percent oflo design flow, in actual practice, upon startup from a refueling outage, RCS total flow is confirmed to be greater than or equal to design How pursuant to SR 3 A.I.4. The actual measured now then becomes the basis for the low flow trip setpoint, nis value will be greater than 90% loop design flow, which is consistent with current TS requhements, but would not be consistent with the li.B. Robinson version of the proposed note.

Dere are times that we need the latitude to set OTDT/OPDT trips conservative (e.g., during startup until they are able to be normalized at near full power equilibrium conditions).

Enclosure 2

4 2.

Discuu the removal of the inequalities for Notes I and 2 to Table 33.1 1 Overtem Setpoint value is the setpoint continuously calculated ac the above nfanced variables also consided nominal values? .

De tem seminal has been app!!ed to the above referenced parameters based on methodology employed at VEOP (consistent with Method i described in section 4.

setpoint methodology). Additionally, limitations apociated with the process required setting selwted parameters snake it dimcuh to unequivocally state that the settings correct side of an inequality, nls is especially true for those gains that may have to be distributed over mm than one card to prevent driving a card beyond ks ihnk.

De ensinowing calculations use each of the refenced paramasers as an exact value or refmace value. De scaling calculations translata/ convert $e T3 proce parameter settings into engineering units for calibration.

De calibrstion process implements the scaled engineering units within the onlibrat accuracy (i.e., tolerance) requirements of the protection system instrumentation.

De principle behind applying the term nominal to the above persmeters is that th will be set as close as practicable to the T5 specified vdue, end'or conservative to t the variable parameters, as procedurally required (i.e., T, T. K4). Den the ovell cha performance will be demonstrated to br. within the calibration tolerance based on kno loputs. Varying the OTDT/OPDT inputs will generate setpoint credits / penalties, an given the calibration set ofinputs inimace the channel will be demonstrated to tap at the calculated setpoi 4

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v'3. ne addition of a

• reset function" note to Tables 3.3.1 1 and 3.3.21.

We would like to point out that the principle of resetting a channel to within its calibration tolerance is an integral part of our procedures for both the channel operational test (COT) I which is perfonned quarterly, and the channel calibration which is performed at i8. month intervals.

Dis practice ;s also a fundamental assumption of the Westinghouse setpoint methodology; i.e.,

the channel must be lea within its calibration tolerance at the beginning of the surveillance period. l furthermore, our TS Bues state for the channel operational test that the setpoint shall be le A set consistent with the assumptions of the current unit specifs serpoint methodology. The Bases for the channel calibration have a similar statement.

. 4.

Provide (or reference) the documents that describe the current setpoint methodology.

SNC acknowledges the need to update the VEGP TS Bases to reference all of the documents which comprise the complete basis for the VEGP setpoints.

s 5.

Discussion of the LSSS and applicability to the "r.ominal" trip setpoint and allowable value.

10 CTR 50.36 refers to limiting safety system settings (LSSS) as settings for automatic protective devices related to those variables having significant bafety functions. The trip setpoint is the parameter that meets this requirement. It is the utting that is the expected value for each l char.nel operational test and each channel calibration. The allowable value is not a setting.

it is a value that has been calculated based on the effects of such phenomena as rack driA, rack measurement and test equipment, rock calibration accuracy, and rack comparator setting accuracy. This is consistent with the history of the evolution of the allowable value, it is also consistent with the VEGP setpoint calculations, NUREG 1431, and the VEGP TS Bases. The allowable value basically provides an acceptance criteria for the Channel Operational Test (COT)(rack portion of channel) for conservative loop operability determinations. The uncertainty components used to establish the allowable value are only a subpart of the total channel uncertainty.

The VEGP Channel Statistical Allowance (CSA)is calculated using the Westinghouse setpoint calculation methodology, which statistically combines rack driA, rack measurement and test equipment, rack calibration accuracy, rack comparator setting accuracy, rack temperature effects, environmental allowance, sensor driA, sensor temperature effects, sensor pressure effects, sensor mesurement and test equipment, sensor calibration accurney, primary element accuracy, end process measurement accuracy. As such, the CSA represents t!'e statistical stvamation of the total channel uncertainty. Tne CSA is added to the trip setpoint and compared to the safety analysis limits to demonstrate that the safety analysis limits modeled in the safety analyses are adequate.

Therefore, the trip setpoint is the definitive value to ensure that the safety analysis limits are maintained, and ultimately the core safety limits are maintained for the purposes of 10 CFR 50.36. Choosing the atlowable value as the LSSS would be non-conservative by the amount of the rack allowances for the channel, and therefore, is not the parameter to ultimately ensure this for the purpose of10 CFR 50.36.

Exceeding a specified trip setpoint value does not necessarily render the reactor protection system incapable of performing its function per 10 CFR 50.36. As long as the channel would have

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• i i functioned (i.e., generate a trip signal) and margin can be demonstrated between the as found j trip setpoint and the safety analysis limit, then the channel would have performed its function.

Note that 10 CFR $0.36 addresses the ability of e protection system to perform its function.

A single channel inoperable should not render the system incapable of performing its

{ function.

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1.

You state that the Allowable Value for Table 3.3.1 1, Function 14.t , Turbine Trip Turbine Stop Va Closure, are propowd to be revised from " 96.7% open' to

• 90% open.' Footnote: I and m of Table 3.3.1 1 are propoi d to be revised to refer to the ' Nominal Trip Setpoint* and delete the inequalities applied M t setpointr,.

a.

Ducribe the method of detecting the percent closure of the turbine stop valve using the valve mou..ted limit switches. What type of position indicators are on valve stems? You state that the valves are either fully open or fully cloud. How fast is the closure time? What is the method for valve closure?

A limit switch is mounted on the valve yoke, in proximity to each valve a stem, ne limit switch is near the top of the stem travel and is normally held in position while the valve is open. When the valve clows, the stem mounted arm moves down with the stem and releases the switch to move to its actuated position. De chuge is switch contact position is interpreted by the SSPS as a turbine trip signal for that valve.

SSPS combines the limit switches in a 4 out of 4 logic circuit to determine if the turbine is tripped.

De turbine stop valves are not designed for modulating service (as opposed to the turbine control valves). De stop valve are fully open when the turbine is in operation and are fully closed when the turbine is tripped. When the turbine is tripped, the stop valves close in less than one minute.

De stop valve are held open against spring force by hydraulic pressure supplied by the

' turbine EHC sys'em. When the turbine trips, hydraulic fluid is released from the stop valve actuators cnd the valves are closed by the unopposed spring foree,

b. In Table 3.3.1 1, Function 14.b, for Turbine Stop Valve Closure, there is a 'P* under the condition column. What does this stand for?

3 he letter P refen to the applicable Condition of the LCO.

c. Discuss further your use of ' Nominal Trip Setpoint'. How do you decide what to set for this value? What are the safety issues related to how accurate this value is set to?

A calculation was performed to determine the NTS provided. It is based on the physical

, layout of the limit switch assembly on the valve.

Since the stop valves are designed to fully close once tripped, any indication that the valve is no longer fully open is sumcient to determine trip status. Reactor trip on turbine trip is an anticipatory trip and should be developed as soon as there is clear indication that the turbine is tripping. Because the stop valves close so quickly, any indication near the fully open position (such as 90% open) provides sumcient assurance that the stop valve is going closed.

i d. Provide a list of the Chapter 15 accidents analyses that relate to the Function 14.b and indicate the 4

impact on these accidents from your proposed revision.

4 Reactor trip on turbine trip is sin anticipatory trip and no credit is taken for it in any of the Chapter 15 accident analyses. Detefore, the proposed TS change has no impact on the accidents described in FSAR Chapter 15.

2. i You state that Notes 1 and 2 to Table 3.3.1 1, Overtemperature 'T and Overpower 'T, respectiv are propowd to be rnised to refer to the ' Nominal Trip Setpoint.' in addition, these notes are l

proposed to be revised to delete the inequalities hem the constants K1 through K6 (except for KS*0 . '

for decreasing temperatures and K6 = 0 for T' T*), and T*, T', and P*.

a.

You state that the uncerialnty calculations assume that the as lea l'lerance (conservative and non conservative direction)is satisfied on a reasonable, sta:Isucal basis, not the nominal condition is satisfied exactly. You Aarthw state that k is acceptable for the as lea condition, immediately aAw calibration of process rock modules for the bistable, to be in the non conservative direction, as long as the magnitude is within the plant procedure specified i calibration tolerance (which has been appropriately reflected in the protection of actuation Ametion specified calibration tolerance). You conclude that therefore the trip seapoint <

inequalities provided in the above noted tables do not define absolute limits for the as lea condition of the process rack modules. De limits are defined by the plant calibration procedures and reflected in the uncertainty calculations. j How is the plant procedure specified calibration toiwance obtained and where is it documented? How do the nominal trip setpoint values compare to the calibration tolerance values?  !

Discussion to be provided at meeting.

b. You state that for the purposes of channel calibration that the values specified in Notes I and 2 to Table 3.3.1 1 for Kl. K2, K3, K4, K5 K6, T*, T', and P* are utilised in the safety analyses  ;

without explicit tolerances, but should be considered as nominal values for instrument '

settings. That is, while an exact setting is not expected, a setting as close as reasonably -

possible is desired. Explain how 'as close as reasonably possible is desired

• would be obtained.

Please indicate the Chapter 15 accident analyses that are afrocted by the Overtemperature 'T l and Overpower 'T trips. Do your proposed change impact these analyses to change the resuhs in a non conservative way.

1 Discussion to be provided at meeting.

3. Please provide a copy of the reference 9, Westinghouse Letter GP.16646, November 5,1997.

De correct letter number is GP 16696. His is a Westinghouse proprietary documw.t. We will be glad to discuss it at the meeting Placing this doument on the docket would require all the legal paper. We can do that if NRC deems necessary.

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oo Here is the listing of transents that use OTDT or OPDT (otmousty they are pnmanly DNB events):

Transient OTDT Pnmary Trip OTDT Backup Trip OPDT Pnmary Trip OPDT Backup Trip Feedwater Teaveioture Reducbon x x Excessive Feedwater Flow x x Excessive Steam Flow x x Inadvertent Secondary Depressurization x x Steam System Piping Failure x Loss of Extemal Load x

Turtxne Trip x Loss of Normal Feedwater x Feedwater System Pipe Break x RCCA Bank Wrthdrawalat Power x x Single RCCA Withdrawal x r x Uncontroled Boron Dilution x In&dvertent RCS Depressurizabon x Steam GereratorTube Rupture x Primary Trip rneans we take explicit credd for the funcbon for one or more of the analyses of the event, e.g., OPDT is for a selected set of intermediate and small steam breaks, but not a large steam breat Backup Tnp means we do not tate explied credd for the funcbon but for one or more of the analyses of the event, the trip setpo:nt is exceeded therefore if we need it, it is out there. This does not rnean that we would satisfy the same event %I., w entena, i.e., we may fa# more fuel or reach higher tenyeiolures or pressures prior to getbng a backup trip.

Ot dously the pivpused change does not affect any of the analyses or change the anayses results in a norx,uie votnre manner. IfI do my job right with the uncertainty cales, your people do their job correctly vnh the scaling cales and procedures and your techs foDow those procedures, the inp willcome ATor BEFORE the SAL

3) The attachment to the requested letter is consdered pier biey. If I am not mistaken, it noted as such in the header. If the NRC wants it formany we will have to provde the usual affidavd and request for withholding.

Will see you tomorrow, I will be driving down in the moming. I wi!! attempt to rneet you for lunch across the street.

RM 7dev (412) 374-5409 ECE-403K CSTEMPGA3RCMEDOC 01G"?S Pare 2 er 3