RBG-44965, Responds to 990324 Telcon RAI Re SLMCPR Calculation Method for RBS Cycle 9 Slmcpr,Per LAR 1998-15 Re Change to TS 2.1.1.2, Reactor Core Safety Limits. Proposed TS Pages, Encl

Responds to 990324 Telcon RAI Re SLMCPR Calculation Method for RBS Cycle 9 Slmcpr,Per LAR 1998-15 Re Change to TS 2.1.1.2, Reactor Core Safety Limits. Proposed TS Pages, Encl

ML20205L725
Person / Time
Site:	River Bend
Issue date:	04/08/1999
From:	King R ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20205L728	List: ML20205L732 RBG-44965, Responds to 990324 Telcon RAI Re SLMCPR Calculation Method for RBS Cycle 9 Slmcpr,Per LAR 1998-15 Re Change to TS 2.1.1.2, Reactor Core Safety Limits. Proposed TS Pages, Encl
References
RBF1-99-0116, RBF1-99-116, RBG-44965, NUDOCS 9904140269
Download: ML20205L725 (5)

Text

Enttrgy Optretions, Inc.

, R!ver Bend Station

. 5485 U b H'ghway 61

.r-w P O Box 220 v

h St. Francisville. LA 70775 Tel 225 336 6225 Fax 225 635 5008 Pick J. King Director Nuclear Safety & Regulatory Attwrs April 8,1999 U. S. Nuclear Regulatory Commission Document Control Desk, OPl-37 Washington,DC 20555

Subject:

River Bend Station - Unit 1 Docket No. 50-458 License No. NPF-47 Request for Addition Information License Amendment Request (LAR) 1998-15, Change to Technical Specification 2.1.1.2,

" Reactor Core [ Safety Limits]"

File Nos.: G9.5, G9.42 RBF1-99-0116 RBG-44965

Reference:

LAR 1998-15, Change to Technical Specification 2.1.1.2, " Reactor Core [ Safety Limits]," RBG-44721, December 16,1998 Ladies and Gentlemen:

In the referenced letter, Entergy Operations, Inc. (EOI), applied for an amendment to the River Bend Statian (RBS) Technical Specification for Safety Limit Minimum Critical Power Ratio (SLMCPR) for fuel cycle 9 operation. EOI and the NRC discussed this request in a telephone conference on March 24,1999. During this discussion, the NRC requested additional information on the SLMCPR calculation method for the RBS Cycle 9 SLMCPR analysis. With input from our reactor vendor, General Electric (GE), our response to the NRC's request is provided below. k Request 1. Please confirm that the safety limit calculation methods used for the RBS Cycle 9 {.

SLMCPR analysis are methods approved by the NRC and list these General Electric documents applicable to RBS.

D

~ ~

D 9904140269 990408 PDR P ADOCK 05000458 PDR

1 Request for Addition Information License Amendment Request (LAR) 1998-15 RBF1-99-0116 RBG-44965 -

April 8,1999 Page 2 of 4 Response: General Electric has confirmed that the recently approved safety limit calculation methods' are consistent with the methods used in the RBS Cycle 9 SLMCPR calculation. These approved methods are in the following GE documents:

(1) Amendment 25 to NEDE-24011-P-A," General Electric Standard Application for Reactor Fuel,"

(2) Revision 1 of NEDC-32505P,"R-Factor Calculation for gel 1, GE12, and GE13 Fuel "and (3) _ NEDC-3260lP " Methodology and Uncertainties for Safety Limit MCPR Evalutions."

Request 2. Please provide information on (1) the accuracy of the SLMCPR process, and (2) the rounding practices used by General Electric.

Response: The values used in the Cycle 8 and Cycle 9 SLMCPR limits are calculated using methods consistent with that in the documents listed above. The methods are standard rounding methods to the nearest 0.01 value. The actual computation includes additional data, which allow these numbers to be confirmed. As part of the NRC's review of the above listed documents, responses to a series of questions, several of which addressed the overall conservatism in the calculational process, were submitted by GE. In response to these questions, GE provided a c)iscussion and justification for the historical rounding practice. Specifically, the GE response regarding rounding stated the following:

"[T]here is an additional-0.005 bias to account for potential round down in the j reported two-digit value for the safety limit. Although the Monte Carlo safety  :

limit values are calculated to five digits past the detimal point, the variation in )

the Monte Carlo values is approximately +0.005 so that only two digits past j the decimal are significant. Thus, the values are reported nominally :a only  ;

two digits using standard rounding practices."  !

i

' Letter, F. Akstulewicz (NRC) to G. A. Watford (GE)," Acceptance for Referencing of Licensing Topical Reports NEDC-3266it Methodology and Uncertainties for Safety Limit MCPR Evaluations;" NEnC-32694P, " Power Distribution Uncertainties for Safety Limit MCPR Evaluation;" and Amendment 25 to NEDE-240ll-P A on Cyde-Specific Safety Limit MCPR." These cover TAC Nos. M97490, M99069, M97491, March 11,1999.

l

Request for Addition Information License Amendment Request (LAR) 1998-15

' RBF1-99-0116 RBG-44965 April 8,1999 Page 3 of 4 The GE response on the rounding practices was included in the NRC's Safety Evaluation Report (SER) and was found to be acceptable by the NRC based on its SER conclusions.

Request 3. With the more " generic" methodology, and with NRC approval of the SLMCPR methodology, the Technical Specifications no longer need to contain notes that refer to specific cycles (TS 2.1.1.2 and TS 5.6.5). If the notes are removed, as long as the values for future cycles are bounded by the TS limit, no future change needs to be made.

Response EOI agrees and herein requests that the notes on these pages be removed as t an administrative change to the proposed amendment. Technical Specification pages reflecting this change are included in Enclosure 1.

l The information supplied by this letter is consistent with the basis of the initial amendment I

request and therefore does not affect the No Significant Hazards Consideration provided in our l original request.

If you have any questions regarding this request or require additional information, please contact Patricia Campbell at 225-381-4615.

~ Sincerely, -

RJK/PLC Enclosure

r Request for addition Information License Amendment Request (LAR) 1998-15 RBF1-99-0116 RBG-44965 April 8,1999 Page 4 of 4 cc: Mr. Robert Fretz, NRR Project Manager U. S. Nuclear Regulatory Commission M/S OWFN 13-D-18 Washington,DC 20555 Mr. George Replogie NRC Senior Resident Inspector P. O. Box 1050 St. Francisville, LA 70775 U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington,TX 70611 Department of Environmental Quality Radiation Protection Division P. O. Box 82135 Baton Rouge, LA 70884-2135 i

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Enclosure 1 Proposed Technical Specification Pages l

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