ML20203D688

Forwards RAI Re MSSV Setpoint Tolerance Change.Response Requested to Be Provided within 30 Days of Date of Ltr

ML20203D688
Person / Time
Site:	Callaway
Issue date:	12/09/1997
From:	Westreich B NRC (Affiliation Not Assigned)
To:	Randolph G UNION ELECTRIC CO.
References
TAC-M99419, NUDOCS 9712160263
Download: ML20203D688 (5)

Text

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!![ December' 9,1997= ,

7-3 w (Mr1Garry L.{Randol)h? . .

F +7 -*EVice PresidentJand 4hief Nuclear Officer &m-H

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-PostTJffice Box 620' " _'C) y g ,

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$0BJECTi REQUESTFORADDITIONAL-INFORMATION(RAI)-REGARDINGMAINSJEAM'

{g ;9p VALVE =SETPOINT-TOLERANCE CHANGE (TAC NO. M99419)

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Dear Mr. Randolph:

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By letter dated August 8:.1997.UnionElectric(UE) submitted;anapplidation'.

e:for amendment to Facility Operating License No. NFP-30 for the Callaway Plant i

, t. hat would change technical specification tables to revise sensor errors 'and; <

" reduce the setpoint tolerances for the main steam line safety valves._

b The staff-has reviewed your submittal and determined that further information.

.is neededito/ complete our review. The requested information is ir.cluded;as-an- .

enclosure to this letter. In order to maintain the. staff's review schedule.

provide your: response within 30 days of the date of this letter. If you have

- any questions regarding<the content of this RAI. please contact me At (301)

.415-3456. ->

Sincerely, i

ORIGINAL SIGNED BY i Barry C. ~ Westreich. Project Manager Project Directorate'IV-2

. Division of Reactor Projects Ill/IV i I

Office of Nuclear Reactor Regulation f Docket No. 50-483 D]STRIBUTION:

MesheadMe** EPeyton

Enclosure:

Request for Additional PUBLIC ACRS T-2E26 A Information PDIV-2 Reading OGC, 015B18 V EAdensam (EGAl) WJohnson. RIV

-cc w/ encl: See next page- WBateman PGwynn RIV-BWestreich TCollins DOCUMENT NAME: R2M9941.RAI 0FC P,D11.2/PM PDIV-2/LA-' .

NAME- N eichiye EPeyhn 12/9-/97 -12/9/97'

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9712160263 971209 o PDR ADOCK 05000483

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pa ateo y* t UNITED STATES s j

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NUCLEA'R RF.GULATORY COMMISSION.

' WASHINGTON, D.C. enmas -j

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%, . . , , , *o December 9,1997 Mr. Garry L. Randolph Vice President and Chief Nuclear Officer Union Electric Company Post Office Box 620 Fulton, Missouri 65251

SUBJECT:

REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING MAIN STEAM SAFETY VALVE SETPOINT TOLERANCE CHANGE (TAC NO. M99419)

Dear Mr. Randolph:

By letter dated August 8, 1997. Union Electric (UE) submitted an application for amendment to Facility Operating License No. NFP-30 for the Callaway Plant that would change technical specification tables to revise sensor errors and reduce the setpoint tolerances for the main steam line safety valves.

The staff has reviewed your submittal and determined that further information is needed to complete our review. The requested information is included as an enclosure to this letter. In order to maintain the staff's review schedule, provide your response within 30 days of the date of this letter. If you have any questions regarding the content of this RAl. please contact me at (301) 415-3456.

Q v

C. Westreich. Project Manager Project Directorate IV-2 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulatior.

Docket No. 50-483

Enclosure:

Request for Additional Information cc w/ encl: See next page

Mr. Garry L.' Randolph1 cc w/ encl: -- .

Professional Nuclear Mr. Otto L. Maynard Consulting. Inc. -President and Chief- Executive Officer 19041 Raines Drive Wolf Creek Nuclear Operating Corporation Derwood.-Maryland 20855 P.O. Box 411-Burlington, Kansas 66839 Gerald Charnoff. Esq.

Thomas A. Baxter. Esq. Mr. Dan I. Bolef, President Shaw Pittman. Potts & Trowbridge Kay Drey, Representative

2300 N. Street N.W. Board of Directors Coalition Washington. 0.C. 20037 for the Environment 6267 Delmar Boulevard Mr. H. D. Bono University City. Missouri 63130 Supervising Engineer

- Quality Assurance Regulatory Support Mr. Lee Fritz Union Electric Company Presiding Commissioner

- Post Office Box 620 Callaway County Court House l Fulton. Missouri 65251 10 East Fifth Street

. Fulton. Missouri 65151 U.S. Nuclear Regulatory Commission Resident' Inspector Office Mr. Alan C. Passwater. Manager 8201 NRC Road Licensing and Fuels Steedman. Miesouri 65077-1302 Union Electric Company Post Office Box 66149 Mr. J. V. Laux. Manager St. Louis. Missouri 63166-5149 Quality Assurance 4

Union Electric Company Post Office Box 620

- Fulton. Missouri 65251 Manager - Electric Department Missouri Public Service Commission 301 W. High Post.0ffice Box 360

Jefferson City Missouri 65102 Regional Administrator. Region IV U.S. Nuclear Regulatory Commission H rris Tower & Pavilion 611 Ryan Plaza Drive. Suite 400 Arlington. Texas 76011-8064 Mr. Ronald A. Kucera. Deputy Director Department of Natural Resources P.O. Box 176 Jefferson City. Missouri - 65102 k

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, UNION ELECTRIC W NY

, CALLAWAY PLANT

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DOCKET N0. 50-483 REQUEST FOR ADDITIONAL INFORMATION REGARDING MSSV TOLERANCE CHANGE In Attachment 2. on pages 7 and 8. the licensee states: l "The revisions to Table 2.2-1 are made to assess the im3act of reducing the high pressurizer pressure safety limit (SAL) from t1e current value of 2445 psig to 2410 psig. This SAL reduction ensures acceptable accident analysis results are obtained to accommodate a relaxation of the main steam safety valve setpoint tolerance to +3/-l% These changes recognize that older generation Barton transmitters, subject to excessive negative drift, are no longer used in this application. This negative drift accounted for 4.25% of the 4.96% of span Z term.

Deletion of this drift term requires that the S term be increased by 1%

of span to account for a typical drift allowance. Thus. Z and S are revised to 0.71% span and 2.0% span, respectively. The reduced SAL directly results in a reduced total allowance (TA), i.e. Since it reflects the difference between the SAL and the nominal trip setpoint 2410-2385 psl9 = 3 .125 % span Boo span / 100% span The decreased TA in conjunction with the increased S term results in a reduced allowable value of 2393 psig."

These changes are reflected in the markup of table 2.2-1. Reactor Trio System Instrumentation Trio Setooints, item 10. Pressurizer Pressure - High, where the Total Allowance (TA) changed from 7.5 to 3.125. the Sensor Error Z changed from 4.96 to 0.71, and Sensor Error S changed from 1.0 to 2.0. The factors in determining the Z and S factors were not discussed or justified. In addition, while it is stated that Barton transmitters are no longer used, the current transmitters were not identified.

1. Provide the following trip function error and drift factors associated with the Pressurizer Pressure - High channel statistical allowance:

a. Process measurement accuracy

b. Primary element accuracy

c. Sensor calibration measurement & test equipment accuracy

d. Sensor pressure effects

e. Sensor temperature effects

f. Sensor drift 9 Environmental albwance

, h. Rack calibration accuracy (Rack accuracy and measurement & test equipment accuracy)

1. Com)arator setting accuracy

j. Racc temperature effects

k. Rack drift

2. The licensee states that the negative drift component of the Barton transmitter accounted for 4.25 percent of the 4.96 percent of the Z term. Describe the uncertainty components incluaed in the 2 term. Are sensor drift uncertain'ies normally included?

3. Describe the uncertainty components included in the value S.

4 Union Electric Company states that the drift term included in S is a typical value. Provide the instrument type that replaced the Barton transmitter and discuss why a " typical drift term" is applicable in the determination of S instead of vendor specific information.

5. Provide the Allowable Value (AV) calculation and the revised uncertainty allowances for the channel statistical allowance. Explain how a r nision to the sensor drift term impacted the AV.

6. Provide a margin calculation confirming that the channel uncertainty is bounded by the " total allowance".

7. Discuss the setpoint methodology used in-this a) plication. If the setpoint methodology is based upon a vendor metlodology, discuss what changes to that vendor report are required by this modification.

Discuss changes in margin in the setpoint calculation, and why a change in margin is at:eptable.

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