ML16131A399

Discusses Proposed Rev to TS Bases for Plant.Rev Re LOCA Linear Heat Rate Limits,Results from Corrections of Errors in B&W LOCA Evaluation Model & Use of Mark B9 Fuel Assembly

ML16131A399
Person / Time
Site:	Oconee
Issue date:	10/01/1992
From:	Wiens L Office of Nuclear Reactor Regulation
To:	Hampton J DUKE POWER CO.
References
TAC-M84085, TAC-M84086, TAC-M84087, NUDOCS 9210080127
Download: ML16131A399 (7)

Text

October 1, 1992 Docket Nos. 50-269, 50-270 and 50-287 Mr. J. W. Hampton Vice President, Oconee Site Duke Power Company P. 0. Box 1439 Seneca, South Carolina 29679

SUBJECT:

PROPOSED REVISION TO TECHNICAL SPECIFICATION BASES FOR OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 (TAC NOS. M84085, M84086, AND M84087)

In a letter dated March 3, 1992, Duke Power Company (DPC) informed the Nuclear Regulatory Commission of changes to the Technical Specification (TS) Bases for Oconee Nuclear Station, Units 1, 2, and 3. These changes involve revisions to the LOCA linear heat rate limits, results from corrections of errors in the B&W LOCA Evaluation Model, and the use of the Mark B9 fuel assembly. You stated that a 10 CFR 50.59 evaluation of the changes was made and that DPC had concluded that the changes did not involve an unreviewed safety question. We have reviewed the changes and concur with that conclusion.

For administrative purposes, the TS Bases change needs to be provided to the staff to enable all copies of the Oconee TS to be updated in a consistent fashion. The revised TS Bases pages are enclosed.

If you have any questions regarding this matter, please contact me at (301) 504-1495.

Sincerely,

/s/

L. A. Wiens, Project Manager Project Directorate 11-3 Division of Reactor Projects -

I/II Office of Nuclear Reactor Regulation

Enclosure:

Revised TS Bases pages cc w/enclosure:

See next page Distribution Docket File/

S. Varga L. Wiens NRC/Local PDRs G. Lainas OGC PDII-3 R/F D. Matthews RS (10)

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 2055 October 1, 1992 Docket Nos. 50-269, 50-270 and 50-287 Mr. J. W. Hampton Vice President, Oconee Site Duke Power Company P. 0. Box 1439 Seneca, South Carolina 29679

SUBJECT:

PROPOSED REVISION TO TECHNICAL SPECIFICATION BASES FOR OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 (TAC NOS. M84085, M84086, AND M84087)

In a letter dated March 3, 1992, Duke Power Company (DPC) informed the Nuclear Regulatory Commission of changes to the Technical Specification (TS) Bases for Oconee Nuclear Station, Units 1, 2, and 3. These changes involve revisions to the LOCA linear heat rate limits, results from corrections of errors in the B&W LOCA Evaluation Model, and the use of the Mark B9 fuel assembly. You stated that a 10 CFR 50.59 evaluation of the changes was made and that DPC had concluded that the changes did not involve an unreviewed safety question. We have reviewed the changes and concur with that conclusion.

For administrative purposes, the TS Bases change needs to be provided to the staff to enable all copies of the Oconee TS to be updated in a consistent fashion. The revised TS Bases pages are enclosed.

If you have any questions regarding this matter, please contact me at (301) 504-1495.

Sincerely, L. A. Wiens, Project Manager Project Directorate 11-3 Division of Reactor Projects -

I/II Office of Nuclear Reactor Regulation

Enclosure:

Revised TS Bases pages cc w/enclosure:

See next page

Mr. J. W. Hampton Duke Power Company Oconee Nuclear Station cc:

Mr. A. V. Carr, Esquire Mr. M. E. Patrick Duke Power Company Compliance 422 South Church Street Duke Power Company Charlotte, North Carolina 28242-0001 Oconee Nuclear Site P. 0. Box 1439 J. Michael McGarry, III, Esquire Seneca, South Carolina 29679 Winston and Strawn 1400 L Street, NW.

Mr. Alan R. Herdt, Chief Washington, DC 20005 Project Branch #3 U. S. Nuclear Regulatory Commission Mr. Robert B. Borsum 101 Marietta Street, NW. Suite 2900 Babcock & Wilcox Atlanta, Georgia 30323 Nuclear Power Division Suite 525 Ms. Karen E. Long 1700 Rockville Pike Assistant Attorney General Rockville, Maryland 20852 North Carolina Department of Justice Manager, LIS P. 0. Box 629 NUS Corporation Raleigh, North Carolina 27602 2650 McCormick Drive, 3rd Floor Clearwater, Florida 34619-1035 Mr. R. L. Gill, Jr.

Licensing Senior Resident Inspector Duke Power Company U. S. Nuclear Regulatory Commission P. 0. Box 1007 Route 2, Box 610 Charlotte, North Carolina 28201-1007 Seneca, South Carolina 29678 Regional Administrator, Region II U. S. Nuclear Regulatory Commission 101 Marietta Street, NW. Suite 2900 Atlanta, Georgia 30323 Mr. Heyward G. Shealy, Chief Bureau of Radiological Health South Carolina Department of Health and Environmental Control 2600 Bull Street Columbia, South Carolina 29201 Office of Intergovernmental Relations 116 West Jones Street Raleigh, North Carolina 27603 County Supervisor of Oconee County Walhalla, South Carolina 29621

LIST OF FIGURES Fiqure Page 3.1.2-1A Reactor Coolant System Normal Operation Heatup 3.1-6 Limitations -

Unit 1 3.1.2-1B Reactor Coolant System Normal Operation Heatup 3.1-6a Limitations -

Unit 2 3.1.2-1C Reactor Coolant System Normal Operation Heatup 3.1.6b Limitations -

Unit 3 3.1.2-2A Reactor Coolant System Cooldown Normal Operation 3.1-7 Limitations -

Unit 1 3.1.2-2B Reactor Coolant System Cooldown Normal Operation 3.1-7a Limitations - Unit 2 3.1.2-2C Reactor Coolant System Cooldown Normal Operation 3.1.7b Limitations -

Unit 3 3.1.2-3A Reactor Coolant System Inservice Leak and Hydrostatic 3.1-7c Test Heatup and Cooldown Limitation - Unit 1 3.1.2-3B Reactor Coolant System Inservice Leak and Hydrostatic 3.1-7d Test Heatup and Cooldown Limitation - Unit 2 3.1.2-3C Reactor Coolant System Inservice Leak and Hydrostatic 3.1-7e Test Heatup and Cooldown Limitation - Unit 3 3.1.10-1 Limiting Pressure vs. Temperature Curve for 100 STD 3.1-22 cc/Liter H20 3.5.2-16a LOCA-Limited Maximum Allowable Linear Heat Rate for 3.5-30 Mark B8 and Earlier Fuel Assembly Designs 3.5.2-16b LOCA-Limited ?hrimum Allowable Linear Rate for 3.5-30a Mark B9 and Subsequent Fuel Assembly Designs 3.5.4-1 Incore Instrumentation Specification Axial Imbalance 3.5-34 Indication 3.5.4-2 Incore Instrumentation Specification Radial Flux Tilt 3.5-35 Indication 3.5.4-3 Incore Instrumentation Specification 3.5-36 vii

Bases Operation at power with an inoperable control rod is permitted within the limits provided.

These limits assure that an acceptable power distribution is maintained and that the potential effects of rod misalignment on associated accident analyses are minimized.

For a rod declared inoperable due to mis alignment, the rod with the greatest misalignment shall be evaluated first.

Additionally, the position of the rod declared inoperable due to misalignment shall not be included in computing the average position of the group for determining the operability of rods with lesser misalignments. When a control rod is declared inoperable, boration may be initiated to achieve the existence of 1% Ok/k hot shutdown margin.

The power-imbalance envelope obtained in accordance with the approved methodology is based on LOCA analyses which have defined the maximum linear heat rate (see Figures 3.5.2-16a and b) such that the maximum clad temperature will not exceed the Final Acceptance Criteria.

Corrective measures will be taken immediately should the indicated quadrant tilt, rod position, or imbalance be outside their specified boundary.

Operation in a situation that would cause the Final Acceptance Criteria to be approached should a LOCA occur is highly improbable because all of the power distribution parameters (quadrant tilt, rod position, and imbalance) must be at their limits while simultaneously all other engineering and uncertainty factors are also at their limits.** Conservatism is introduced by application of:

a.

Nuclear uncertainty factors

b.

Thermal calibration

c.

Hot rod manufacturing tolerance factors The 25% + 5% overlap between successive control rod groups is allowed since the worth of a rod is lower at the upper and lower part of the stroke.

Control rods are arranged in groups or banks defined as follows:

GrouiE Function 1

Safety 2

Safety 3

Safety 4

Safety 5

Regulating.

6 Regulating 7

Xenon transient override 8

APSR (axial power shaping rod)

Actual operating limits depend on whether or not incore or excore detectors are used and their respective instrument calibration errors.

The method used to define the operating limits is defined in plant operating procedures.

3.5-11

LOCA-Limited Maximum Allowable Linear Heat Rate For Mark B8 and Earlier Fuel Assembly Designs 20 18 J

417.0) 9X 16.6) 16 1(16.1)

(16.1) 1

.0)

(15.5 r-4

• (14.5)

O r4

-1000o MWd/mto

-'-After 1000 MWd/mtu 12 X

0 0

2 4

6 8

10 12 Axial Location of Peak Pover From Bottom of

Core, ft Oconee Nuclear Station Figure 3.5.2-16a 3.5-30

LOCA -Limited Maximum Allowable Linear Heat Rate For Mark B9 and Subsequent Fuel Assembly Designs 18 44 4-ft

10650, 17.5) 1768,10-ft (10650, 17.0) 2 rfrl0-ft

\\(43333, 16.7)

(D 4,8,16-ft 44 UUU, 16.5)

(44667, 16.3) 16 15 O

0 14 E

13 x

(57000, 12.6) 12 I

0 10000 20000 30000 40000 50000 60000

Burnup, MWd/mtU Oconee Nucleax Station Figuze 3.5.2-16b 3.5-30a