ML20101F238

Forwards Suppl 1 to Application for Amend to License NPF-86, Consisting of License Amend Request 92-01,revising TS Re RTD Bypass Sys Elimination

ML20101F238
Person / Time
Site:	Seabrook
Issue date:	06/19/1992
From:	Drawbridge B PUBLIC SERVICE CO. OF NEW HAMPSHIRE
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20101F241	List: ML20101F238 ML20101F255 ML20101F284
References
NYN-92081, NUDOCS 9206240345
Download: ML20101F238 (10)

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"New Hampshire Yankee NYN- 92081 June 19,1992 United States Nuclear Regulatory Commission Washington, D.C. 20555

' Attention: ' Document Control Desk

- R efere nces: -(a) Facility Operating License No. NpF-86, Docket No. 50-443 (b)- ' NHY- Letter NYN-92035 dated March 20, 1992, " License Amendment Request 92-01; RTD Bypass System Elimination," T. C. Feigenbaum to NRC Sbbject: Suppl.ement I to License Amendment Request 92-01, RTD Bypass System Elimination Gentlemen:

New Hampshire Yankee (NHY)_ submitted License Amendment Request 92 01, RTD Bypass-System-Elimination, to the NRC on March 20,1992 [ Reference (b)]. The NRC Staff subsequently . requested additional information consisting of 17 questions; 13 from the Instrumentation and- Controls System Branch and 4 from the Reactor Systems Branch. New Hampshire _ Yankee, NRC _and- Westinghouse personnel discussed NHY's responses to these 1 requests-inrconference calls on June 9 and June 12, 1992. The New Hampshire Ya.nkee responses to; the NRC requests for additional information are provided herein in Er. closure L

During' the June 12, 1992 conference call, the ' Reactor Systems Branch - personnel stated that . NHY's proposed change to Technical Specification Limiting Condition for Operation- (LCO) '3.2.5 represented a line item improvement to Standard Technical

Specifications and therefore could not be reviewed on an individual plant basis, however -

NHY could propose the change on a lead plant basis. New Hampshire Yankee had proposed to change 'he Reacter Coolant System flow rate requirement of LCO 3.2.5 by specifying the thermal design flow analysis value instead of the currently stated flow value which includes measurement uncertainty. This change was proposed to provide consistency in LCO 3.2.5 which currently: specifies the analysis value for RCS average temperature and pressurizer

- pressure. The_ proposed change was also= intended- to enhance oparator flexibility in the selection of the instrumentation used for RCS flow measuremerit.

In : light - of the -NRC position on the proposed change to LCO 3.2.5, NH Y has

proposed alternative changes to LCO 3.2.5 and its BASES which specify RCS flow inclusive

- of measurement uncertainty. A markup of the alternative changes to LCO 3.2.5 and its

' BASES and a retype of the proposed changes are provided 'in Enclosure 2, Section 11 and 111 respectively.- The_ proposed RCS flow rate value is 392,000 gpm (thermal design flow of i

'9206240345 920619 lQ,' O PDR. ADOCK'05000443 P l mw ompsnire 1onkee Division of Public Service Company of New Hampshire i g

P.O. Box 300

• Seabrook, NH 03874

• Telephone (603) 474-9521 I

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United States Nuclear Regulatory Commission June 19,1992 Attention; Document- Control Desk Page two L

382.800 gpm plus a flow measurement uncertainty of 2.4% flow). The basis for the 2.4%

uncertainty value is' discussed in the response to Reactor Systems Ilranch question number

- 2 see Enclosure 1. Additionally, NHY notes that it i= hereby withdrawing the proposed clarifying changes to Technical Specification BASES page 112 5 which were submitted with LAR 92 01, These proposed changes to page !! 2-5 are being withdrawn to ensure conformance with Standard Technical Specifications.

To facilitate NRC review of Supplement I to License Amendment Request 92 01, NilY has enclosed as Enclosure 2 a stand alone document which is to be used in its entirety in p; ace of_the original - License Amendment Request 92 01. Supplement I to License Amendment Request 92-01 has been reviewed and approved by the NilY Station Operation Review Committee and the Nuclear Safety Audit Review Committee. A copy of this letter and the enclosed Supplement 1 to License Amendment Request 92 01 have been submitted to the State of New Hampshire LiSon Officer pursuant to 10CFR50.9t(b).

New llampshirc Yankee requests NRC review of Supplement I to I.icense Amendment Request 92-01 and issuance of a license amendment by August 15, 1992. This schedule is proposed in support of NHY's plans to implemea.t the RTD Bypass System Elimination design change during the second refueling outage which is scheduled to begin on September 7,1992.

Should you require further additional information regarding Supplement I to License Amendment Request . 92 01,. please contact Alr. Terry L. Ilarpster, Director of Licensing Services, at (603) _474-9521, extension 2765. _

Very trulyjyours.

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Tiruce 1,/ ' aN ff[

rawbridge Executive Director Nucleir Production

'i-TCF:ALL/ss/act Enclosure cc: hir Thomas T. Martin Alr. George L Iverson, Director Regional ' Administrator NH Office of Emergency Management U. S. Nuclear Regulatory Commission 107 Pleasant Street Region 1 Concord, Nf! 03301

' 475 Allendale Road King of Prussia, PA 19406 Mr. Gordon E. Edison Mr. Ted C. Feigenham Sr. Project Manager President & CEO e - Project Directorate - I-3 P.O. Box 300 Division of Reactor Projects Seabrook, NH 03874 U.S. Nuclear Regulatory Commission Washington, DC 20555 Mr. Noel-Dudley NRC Senior Resident inspector l P.O. Box 1149 Seabrook, Nil 03874 I

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New llampshire Yankee June 19,1992 l

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I ENCLOSURE 1 TO NYN-92081  !

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-Response - to . NRC . Instrumentation.- and Controls Systems Branch requests for 1 additional information regarding NITY License Amendment Request 92-01; RTD Bypass Elimination.

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EEC Ouestion 1 Is thefresponse time--testing methodology in 2.1 (WCAP-13181) Loop Current Step Response ^(LCSR) testing?

l NHY Response RTDs have been tested at the manufacturer's facilities for time renponse. The test was a plunge test which assured compliance to procurement specifications.

The in-situ testing referred to in WCAP-13181 section 2.1 is Loop Current Step

Response (LCSR) testing. This testing will assure that the RTD performance is.

in accordance with the safety analysis assumptions.

.NRC Ouestion 2 Seabrook does not use a median signal selector arrangement for T,, and AT inputs to the control system. Are the requirements for control system / protection system  ;

interaction satisfied with the present input arrangement? l.

NHY-Response All requirements for control system / protection system interaction are satisfied with the design described in WCAP-13181. The Median Signal Selector is designed for a three loop plant to provide control signals and to meet control / protection interaction requirements. Seabrook's two out of f our chant.el logic configuration  ;

precludes the need_for a median selector.

'NRC Ouestion'3 Is the plant computer used for data collection to calculate daily heat balance or: control board instrumentation?

NHY Response ,

l The Main Plant Computer System (MPCS) is used for data collection and calculation of the daily heat balance. ,The heat balance calculation is performed every 30 seconds. In the event that the MPCS is unavailable main control board instrumentation is used for the heat balance data collection.

Additional 1nfocmation with-regard to the precision calorimetric is provided in the' response =to questions 9 and 13.

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NRC Ouestion 4 AEe there any control board. modification being performed besides the removal of bypass flow alarms?

NHY Response

'There are no other physical Main Control Board (MCB) modifications to be performed as a result of the RTD Byphus Elimination project. New analog inputs

.have been added to the plant computer for each individual RTD. These are available to the operator on computer display's on the MCB.

NRC Ouestion 5 Will the plant use cross calibra+1on techniques for ::alibration of the thermowell mounted RTDs? Is the plant intending to perform the calibration with an RTD

. reference installed at each calibration?

NHY Response Cross calibration techniques for calibration of the thermowell mounted RTDe will be_ performed during startup after each refueling.

Westinghouse.does not require the replacement of any RTDs for cross calibration The Westinghouse position is that the drift exhibited by the multiple RTCs is random:without a systematic component being noted. This position has - been supported by NUREG _ CR _ $$60 = " Aging - of Nuclear Plant Resistance Temperature Detectors" which concludes on page 144.

• Cross calibration is an ef fective method for verifying the consistency of a group of RTDs. This method does not account f or _ common mode drif t or. any other systematic calibration problem unless one or more newly calibrated.RTDs are included in the test, However, the f act that the drift of RTDs is usually random justifies the use of cross calibration ar.a viable method even without including refereace RTDs".

NRC-Ouestion 6 Is the total response time of 6 secondo a safety analysis limit as well' as the TS value?

NHY Response The - total- response - time used in the safety analysis is.six seconds. The NHY Technical Requirements Manual lists the response time values for Overpower and Overtemperature Delta T temperature sensors = as four seconds for Technical-

Specification surveillance testing. This ~ agrees with the value in the Technical

' Specifications Bases. This four second value does not include the two additional seconds allocated in the safety analysis for electronics delay (please see Table-2,1-1.on page'13 of WCAP 13181).

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NRC Ouestion 7 Hac ~ the uncertainty for T.,, been revised to 15*F due to RTD replacement? The value.for T,,, remain the same? ,

NHY Resnonse .

-Revision of T,yg- uncertainty to i 5'F is due to incorporation of a T, worst case

' streaming -of an additional l'F. The nominal value f or T,,, at 100% power remains

-the-same, NRC Ouestion 8 Tablei3.1-1-(WCAP-13181)-lists a rack bias of 1. What is this bias?

NHY Response The bias-is included due to cold leg streaming described in the response to (question 7.-

, NRC Ouestion 9 l

'! Is the M&TE term listed in both the RMTE and SMTE Table 3.1-2 (WCAP-13181):

> combination?-

NHY Response The M&TE term listed on Table 3.1 2 is the uncertainty of the M&TE utilized in calibration of the sensors for the applicable function, SMTE.

During the performance of the. precision calorimetric, data is taken at various loca tions per- plant procedures with attention given to the sensitivities of the calorimetric-calculation, risk of spurious trips, and ease of data collection for acceptabli results.- The RDOT uncertainty identified in Table 3.1-2 is a combination o. the uncertainties as sociated L with t'. e data collection for the-specific fr- . a and adjusted according to the data collection process.

For Feedwater temperature the readings are taken locally with M&TE, therefore the RDOT term incorpcrates uncertainties due to temperature ef fects and' test

~ equipment.

For" Feedwater pressure. - the Main Control Board meter is utilized. In this

-instance- the RDOT term represents the calibration of the racks, RMTE, rack

-- temperature ef fects , isolator accuracy, and the Main Control Board meter

-. accuracy .

For Feedwater DP indication, . two channels are read-with M&TE at test points -

within 'the. process racks. - The.RDOT represents those portions of the racks which have'been calibrated the RMTE for the M&TE utilized for the calibration and data

- collection, rack temperature effect, and reduced by the square root of the number of channelo-averaged..

4 For--Steamline pressure three channels are read with M&TE at test points within the process racks. The RDOT represents those portions of the racks which have been calibrated, the RMTE utilized for the calibration and data collection, rack 3

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3 temperature _ effect, -ands reduced by the square-root of-the number of channels

- averaged.

LThe Tg and T[: RDOT term includes 'M&TE uncertainties associated with local readings. . therefore rack terms are not applicable.

Pressurizer -pressure Ldata is taken from the process racks and the RDOT term .r represents those portions of the racks which are utilized and the calibrated accuracy, the RMTE utilized for the calibration and data collection, and the rack temperature effect.

NRC Ouestion 10

-Why are no rack terms listed in Table 3.1-2 (WCAP-13181)7 NHY Response The applicable portion of the rack terms are included in the RDOT term. For spec,tfic information see response to question 9.

NRC Ouestion 11 Sensor drif t RTDs is equal to zero in Table 3.1-2 (WCAP-13181) . Is this correct?

NHY Response Drif t values identified in WCAP.13181 are based on an 18 month calibration cycle. '

The_ RTD - cross calibration is performed on the heatup following a refueling outage. .The readings for the calorimetric are typically taken after refueling during startup. No allowance for RTD drift is considered necessary over_the relatively short time frame from the cross calibration to the calorimetric. See

- the response to question 5 for additional information on RTD drift.

NRC Ouestion 12 Table 3.1-8L(WCAP-13181): Why is the overpower-AT' Cold Leg streaming bias of

-a different value than that shown for overtemperature AT.

NHY Response Overtemperature AT cold leg streaming bias is based on a 1 *F Tc streaming

-uncertainty. This u_ncertainty is af f ected by the K2 value in the overtemperature AT' . equation of the Technical Specifications and converted to percent AT span for inclusion in the channel statistical allowance. The overpower AT cold leg streaming bias -is based on-the same l'F T, streaming uncertainty and is af fected '

by the K 6 value in the overpower AT equation of the Technical Specifications and converted to~ percent AT span for inclusion in the channel statistical-allowance . _ - The dif f erence in 2 K and K account for the difference in the 6

streaming bias-values.

NRC Ouestion'13-The DNB parameters now list RCS flow as an analytical value of 382,800 gpm.

Explain what--a change tc an analytical value for RCS flow (DNB parameters) l provides for versatility in the selection of instrumentation for measurement of l'

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Q RCS _ flow? _ Reference page . 4 of amendment request. Is the RCS flow value reference the thermal design limit? How will measurement' uncertainties for RCS

. flow be accounted for-'in the TS/ operating procedures?

NHY Response An alternative change to Technical Specification Limiting Condition for Operation (LCO) 3.2.5'has been proposed in License Amendment Request 92-01_ Supplement 1.

The RCS flow LCO in Technical Specification 3.2.5(c) has been changed from the current 391,000 gpm (thermal design flow of 382,800 gpm plus the cold leg e'. bow tap flow uncertainty of 2.1% tiow) to 392,000 gpm [ thermal design flow of 382.800 gpm plus the cold leg elbow tap flow uncertainty of 2.4% flow).

The footnote at the bottom of Page 3/4 ' 2-10 has been revised to reflect the increase of-the cold leg elbow tap flow uncertainty f rom 2.12 to 2.42. The revised cold leg elbow tap flow uncertainty includes the 2.3% cold leg elbow tcp flow uncertainty documented in_WCAP-13181 plus an additional penalty of 0.1%

specified by _the Bases for Technical Specification 3/4.2.5 to account for undetected feedwater venturi fouling.

The Beses for Technical Specification 3/4.2.5 has been changed to reflect the revised cold leg elbow tap flow uncertainty.

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1, l Response to NRC Reactor Systems Branch requests for additional information regarding NUY License Amendment Request 92-01; RTD Bypass Elimination.

NRC Ouestion 1.

Discuss how-you calibrate the RTDs to determine their accuracy. What is the  ;

reference temperature and how do you account for the drif t between calibrations? l NHY Response The RCS RTDs were calibrated by the manufacturer using a reference temperature bath prior to shipment to the site. After the RTDs are installed, a cross calibration, or comparison, will be done to verify that the calibration has not changed due to installation affects. The average of the RTDs will be the reference temperature for the cross calibration. An uncertainty for drift has been incorporated into the Over Power and Over Temperature Delta T Reactor Trip Setpoint calculations.

NRC Ouestion 2.

I We require a flow measurement uncertainty value in the Techn. cal Spe[ifications

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l that'is based on an uncertainty analysis using plant specific instrumentation.

If you use various instruments, a bounding analysir can be used. If you are using various combinations of instrumentation, then the uncertainty for each combination will be needed. It in noted that a 0.1% fouling is to be added to the flow measurement uncertainty as you have discussed in the basis.

NHY Response An alternative change to Technical Specification Limiting Condition f or Operation (LCO) 3.2.5 has been proposed in License Amendm'nt Request 92-01 Supplement 1.

The RCS flow LCO in Technical Specification 3.2.5(c) has been changed from the current 391,000 gpm [thernal design flow of 382,800 gpm plus the cold leg elbow tap flow uncertainty of 2.1% flow] to 392,000 gpm (thermal design flow of 382,800 gpm plus the cold leg elbow tap flow uncertainty of 2.42 flow).

The footnote at the bottom of Page 3/4 2-10 has been revised to reflect the increase of the cold leg elbow tap flow uncertainty f rom 2.1% to 2.4%. The revised cold leg elbow tap flow uncertainty includes the 2.3 cold leg elbow tap flow uncertainty documented in WCAP-13181 plus an additional penalty of 0.1%

specified by the Bases for Technical Specification 3/4.2.5 to account for undetected feedwater venturi fouling.

The Bases for Technical Specification 3/~ _ 5 has been changed to reflect the revised cold leg elbow tap flow uncertainty.

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NRC Question 3. -i What method.do.you use-to obtain the RTD response time at each' refueling.

NHY-Response 7

RTD time' resp 6nse was measured by the manuf acturer prior to shi;unent to the site '

by~the performance of a plunge test. .NHY plans t'o' measure RTD time responso

- following installation in - situ by the use of the. loop current step response method. It is anticipated that the loop current step response method will be.

used for future in situ time response testing of the RTDs, NRC Ouestinn'4.

Do you periodically perform surveillances to confirm that gradually failed RTDr (though-unlikely) can be detected?

NHY Response Cross cellbration, ' or comparison, of the thermovell mounted RTDs vill be performed during startup af ter each refueling. The Technical Specifications also require a channel check of the RCS temperature channels every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. These tests.should detect the gradual failure of an RTD.

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