ML20210C506

Forwards Application for Amend to License DPR-6,changing Tech Spec Section 5.2.1.b by Adding Table of Uncertainty Factors Associated W/Analysis of Core thermal-hydraulic Parameters Heat Flux,Maplhgr & Max Bundle Power.Fee Paid

ML20210C506
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	02/04/1987
From:	Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20210C509	List: ML20210C506 ML20210C596 ML20210C634
References
NUDOCS 8702090402
Download: ML20210C506 (3)

Text

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@M SYMM M Consumers Power General o hoes 1946 West Pomen Road. Jackson MI 49201 e (517) 788-1636 x

Director bclear Lkeming w ,,

February 4, 1987 i

Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-155 - LICENSE DPR BIG ROCK POINT PLANT -

CORE THERMAL-HYDRAULIC LIMIT TECHNICAL SPECIFICATION CHANGE REQUEST AND RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION The enclosed proposed changes to Section 5.2.1.b of the Big Rock Point Technical Specifications are being submitted as requested by the NRC staff.

These changes and enclosed replies are provided in response to the NRC's Request for Additional Information dated January 30, 1987 and in response to the NRC's partial denial of our December 5, 1986 Hybrid Control Rod Technical Specification Change Request, by telephcne conference February 2, 1987.

In response to the NRC staff's first two questions in their January 30, 1987 letter, a change to Section 5.2.1.b is proposed which adds a table of uncertainty factors associated with the analysis of the core thermal-hydraulic parameters heat flux, minimum critical. power ratio (MCPR), eaximum average planar linear heat generation rate (MAPLHGR) and maximum bundle power.

Footnotes are also provided delineating the manner in which these uncertainty values are to be used in establishing conformance with associated thermal-hydraulic limits. These uncertainty factors were previously derived as a part of the Big Rock Point Physics Methodology Topical Report, Revision 3 approved by your letters of September 16, 1982 and February 9, 1983. With the addition

of this table of uncertainty factors, the manner in which conformance with the fuel thermal-hydraulic limits has been assured since development of the physics methodology report would be embodied in the Technical Specifications.

Additional details of our administrative procedures for applying these uncertainties and for monitoring conformance to these Technical Specification limits are provided in the discussion section supporting the attached proposed Technical Specification Change Request.

Additional information important to understanding the manner in which reactor core monitoring at Big Rock Point is performed is offered as follows:

First, the limits against which the thermal-hydraulic results of the GROK computer code are compared (taking into account uncertainty factors) are the limits presented in Section 5.2.1.b of the Technical OCO287-0208-NLO4 0 N j)d N 8702090402 870204 ADOCK 050 5, M

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Nuclear Regulatory Commission 2 Big Rock Point Plant TSCR - Core Thermal-Hydraulic Limit February 4, 1987 l Specifications. There is no recalculation of these limits during the course of the cycle. The limits as stated in the Technical

, Specifications apply and are used throughout the entire cycle. The

GROK code is used to calculate the margin to these Technical j Specification limits. As stated in the introductory paragraph to Section 5.2.1.b of the Technical Specifications, reactor operation is limited to be consistent with the most conservative of these limits.

I That is, the most restrictive of these limits (ie, the limit having l the least margin) is used to determine the maximum allowable power

permitted at any point in the cycle, thus assuring conformance with

. all of the thermal-hydraulic limits of this section of the Technical Specifications.

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Second, there is no preplanned power derating program. Rather, the more detailed method of controlling conformance with thermal-hydraulic I limits, described in the discussion section supporting the attached proposed Technical Specification change, is used. This method results in an almost continuous surveillance of core operating conditions by the plant Reactor Engineer and requires his in-line approval for the

! withdrawal of each notch of the control rod withdrawal sequence. As stated in the discussion section of the attached proposed change, the calculations performed prior to releasing notches for withdrawal include the actual operating history of the core and each fuel bundle up to that point in the cycle. Additional uncertainties associated i with " preplanned" predictive calculations as to the manner in which

! the core is actually operated throughout the cycle are thus eliminated. Given the uniqueness of the Big Rock Point reactor in that fuel thermal-hydraulic limits are expected to dictate the maximum i permissible power level as opposed to the design core power (240 MWt )'

it is,important that this method be used to assure compliance with thermal-hydraulic limits for both safety as well as economic reasons.

Third,-this method of reactor core status monitoring and application of uncertainties has been reviewed with the NRC on a number of occasions and found to be acceptable. Commitment to apply the thermal-hydraulic uncertainties to the GROK analyses appears in our  ;

submittals concerning the physics methodology report and is i acknowledged in the staffs first Safety Evaluation Report on this subject. Additionally the Nuclear Regulatory Commission Region III has audited our methods of conformance with the Technical Specifica-tion thermal-hydraulic limits and has had no findings in this area.

l In response to the NRC staff's third question in their January 30, 1987 letter, Consumers Power Company commits to submit for NRC approval a continuing surveillance program for future cycles for the hafnium hybrid control rods based on the results of the Cycle 22 inspections. The long term l surveillance program will be subiitted prior to operation with these control blades after Cycle 22 and it will include the additional design information requested.

I OC0287-0208-NLO4

Nuclear Regulatory Commission 3 Big Rock Point Plant TSCR - Core Thermal-Hydraulic Limit February 4, 1987 In view of the fact that these proposed changes have been requested by the NRC staff as a result of their review of our previous Hybrid Control Rod Technical Specification Change Request, Consumers Power Company requests that this change be processed as an emergency change. Our current plans are to restart Big Rock Point from the current refueling outage about February 23, 1987.

These proposed changes are administrative in nature in that they do not request departure from previously NRC approved practices for Big Rock Point.

The intent of the changes is to relocate NRC approved core thermal-hydraulic monitoring uncertainties from the Physics Methodology Topical Report into the Technical Specifiestions. The NRC's desire to make these Technical Specification modifications was not made known to Consumers Power Company with enough lead time to request a Technical Specification Change Request that would allow the normal public noticing time period. Failure of the NRC to expedite this change request threatens our returning Big Rock Point to power operation and therefore meets the criteria of 10CFR50.91(a)(5) for an emergency change.

Pursuant to 10CFR170.12(c) a check in the amount of $150.00 is included with this application.

M4 edy .

Kenneth W Berry Director, Nuclear Licensing CC Administrator, Region III, NRC NRC Resident Inspector - Big Rock Point Attachment OC0287-0208-NLO4

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