ML20209C587

Forwards SER Input Re Pump Flywheel Integrity.Structural Integrity of Flywheels Adequate to Withstand Forces Imposed by Overspeed Transients W/O Loss of Function.Integrity Mantained by Periodic Insp

ML20209C587
Person / Time
Site:	Satsop
Issue date:	11/07/1983
From:	Johnston W Office of Nuclear Reactor Regulation
To:	Novak T Office of Nuclear Reactor Regulation
References
CON-WNP-1468 NUDOCS 8311160194
Download: ML20209C587 (5)

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. .f i &v NOV 7 1983 Docket No. 50-508 MEMORANDUM FOR: Thomas M. Novak, Assistant Director

- for Licensing Division of Licensing FROM: William V. Johnston, Assistant Director Materials, Chamical and Environmental Technology Division of Engineering

SUBJECT:

PUMP FLYWHEEL INTEGRITY - WNP UNIT 3 Plant Name: WNP Unit 3 Suppliers: Combustion Engineering Licensing Stage: OL Docket Number: 50-508 Responsible Branch and Project Manager: LB-3, A. Vietti Reviewer: S. J. Bhatt Requested Completion Date: October 28, 1983 Description of Task: SER Input - Pump Flywheel Integrity Review Status: Complete .

The Component Integrity Section of the Materials Engineering Branch, Division of Engineering, has reviewed the Pump Flywheel Integrity submitted in the FSAR. Our Safety Review is attached.

Original si;nd t'/

B. D. Liaw 1 William V. Johnston, Assistant Director i Materials, Chemical and Environmental

. Technology Division of Engineering

Attachment:

As stated

Contact:

S. J. Bhatt x-27742 4

g ADOCK 05000 8

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. Thomas M. Novak NCV 7 1983 cc: R. Vollmer D. Eisenhut E. Sullivan F. Miraglia S. Pawlicki B. D. Liaw W. Hazelton R. Klecker C. Cheng G. Knighton A. Vietti S. Bhatt DISTRIBUTION:

MTEB Reading Files MTEB WNP 3 l

') :MTEB DEiMTEB DE JEB l DE: :MCET l S., jBhatt:as/ jar R. W. Klecker B. 'l.i aw W. V. Johnston 11/1/83 11/ t /83 11/ \ /83 11/ L- /83

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ATTACHMENT

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WASHINGTON PUBLIC POWER SUPPLY SYSTEM WASHINGTON NUCLEAR PROJECT NO. 3 a . .. DOCKET.50-508 . .

MATERIALS ENGINEERING BRANCH SAFETY EVALUATION REPORT Pump Flywheel Integrity The safety objective of this review is to assure that the integrity of the primary reactor coolant pump flywheel is maintained to prevent failure at norm'al ope. rating speeds and speeds that might be reached under accident conditions and thus preclude the generation of missiles.

The basis for review is outlined in Standard Review Plan (SRP),

Section 5.4.1.1 and the Regulatory Guide 1.14, which describes and recommends a method acceptable to the NRC staff in implementing -

General Design Criterion 4, " Environmental and Missile Design Bases,"

of Appendix A of 10 CFR Part 50 with regard to minimizing the potential l

for failure of flywheels of the reactor coolant pump.

Evaluation

a) Materials and Fabrication -

Flywheels are fabricated from ASTM, A-543, Grade B, Class 2 plate. The-material is produced by a process that minimizes flaws and improves fracture toughness properties. The materials as well as finished flywheels are sub-jected to 100 percent volumetric ultrasonic inspection using procedures and acceptance standards specified in Section III of the ASME Code.

r g-The nil-ductility transition temperature (NOTT) of the. flywheel material .

is obtained by two drop weight tests (DWT) which exhibit "no break" perform-ance at -5'F in accordance with ASTM E-208. The Charpy V-notch energy level is at least 50 foot pounde in the WR orientation at 70*F. Hence, the RT NDT of 10*F can be assumed. The above drop weight tests also demonstrate that the NDTT of the material is no higher than 10'F.

b) Design Basis The calculated stresses at the operating speed, due to centrifugal forces and the interference fit on the shaft, are within the Regulatory Guide limits. The pump runs at 1190 rphs and may operate briefly at overspeed of 110 percent during the loss of outside load. The design speed is 125 percent of the operating speed. The flywheels are also tested at 125 per-

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l cent of the maximum synchronous speed of the motor. The combined stresses at the design overspeed, due to interference fit and centrifugal forces, are within the Regulatory Guide limit.

l l The flywheels can be inspected by removing the cover. Hence, any crack that develops can be noticed. The critical crack length at the key-ways, l where the stress concentration is high, is about 6 inches at the design l

l overspeed.

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.n c) Eva.luation . . .

We have reviewed the material fabrication, design and inspection aspects of the pump flywheels for compliance wiht the Regulatory Guide 1.14. We have concluded that the structural integrity of the flywheels is adequate to withstand the forces imposed by overspeed transients without the loss of function, and the integrity will be verified periodically by inspection to assure that the integrity is maintained.

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