ML17244A808
| ML17244A808 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 08/15/1979 |
| From: | Ziemann D Office of Nuclear Reactor Regulation |
| To: | White L ROCHESTER GAS & ELECTRIC CORP. |
| References | |
| TASK-03-10.B, TASK-RR NUDOCS 7909100601 | |
| Download: ML17244A808 (7) | |
Text
Mr. Leon D. White, Jr.
Vice President Electric and Steam Production Rochester Gas 5 Electric Corporation 89 East Avenue Rochester, Nevi York 14649
Dear Mr. White:
Docket. 50-24 N
Local PDR
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y g 197g ORB82 RDG NRR RDG DEisenhut, Docket No; 50-244 BGrimes RVollmer WGammi1 1 JMi.1 1 er, LShao TCarter OELD OI8 E(3)
DLZiemann TWambach RSnaider TCheng RE:
TOPIC III-10.B - PUMP FLYWHEEL INTEGRITY R. E.
GINNA NUCLEAR POWER PLANT HSmith
,, JRBuchanan
'TERA ACRS(16)
Enclosed is a copy of our draft evaluation of Systematic Evaluation Program Topic III-10.B, Pump Flywheel Integrity.
You are requested to examine the facts upon which the staff has based its evaluation and respond either by confirming that the facts are correct,'or by
- identifying any errors.
If in error, please supply corrected information for the docket.
We encourage you to supply for the docket
'ny other material related to this topic that might affect the staff's evaluation.
Your response within 30 dhys of the date you receive this letter is requested.
If no response is received within that time, we will assume that you have no comments or corrections.
Sincerely, Original Signei by:,
Dennis L. Ziemann Dennis L. Ziemann, Chief Operating Reactors Pranch 82 Division of Operating Reactors
Enclosure:
Topic III-10.B cc w/enclosure:
See next page OrT ICa~
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TWambach 8/y-/79 DOR: ORBIII2
'LZiemann
, 8//5/79
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Mr. Leon D. White, Jr.
AUG 15 1979 CC Lex K. Larson, Esquire
- LeBoeuf, Lamb, Leiby 5 MacRae 1757 N Street, N.
W.
Washington, D. C.
20036 Mr. Michael Slade 1250 Crown Point Drive
- Webster, New York 14580 Rochester Committee for Scientific Information Robert E. Lee, Ph.D.
P, 0.
Box 5236 River Campus Station Rochester, New York 14627 Jeffrey Cohen New York State Energy Office Swan Street Building
'ore 1, Second Floor Empire State Plaza
- Albany, New York 12223 Di'rector, Technical Development Programs State of Ney York Energy Office Agency Building 2 Empire State Plaza
- Albany, New York 12223 Rochester Public Library 115 South Avenue Rochester, New York 14604 K M C, Inc.
~ ATTN:
Hr. Richard E. Schaffstall 1747 Pennsylvania
- Avenue, N.
W.
Suite 1050 Washington, D.
C.
20006
f i i'I
% 1.
SYSTEMATIC EVALUATION PROGRAM PLANT SYSTEMS/MATERIALS R. E.
GINNA NUCLEAR POWER PLANT UNIT NO.
1 TOPIC III-10.8 PUMP FLYHHEEL 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 normal operating speeds and speeds that might be reached under accident conditions and thus preclude the generation of missiles.
Information for this assessment was obtained from the Final Facility Description and Safety Analysis Report, Technical Supplement Accompanying Application to Increase Power (1971), Technical Supplement Accompanying Application for a Full-Term Operating License (8/1972),
and the Technical
'Specifications for the R. E. Ginna Nuclear Power Plant Unit No. l.
,The basis for the review is the degree of compliance with the recommendations of Regulatory Guide 1.14, "Reactor Coolant Pump Flywheel Integrity".
This guide describes and recommends a method acceptable to the NRC staff of implementing General Design Criterion 4, ".Environmental and Missile Design Bases",
with regard to minimizing the potential for failure of the flywheels of the reactor coolant pump motor.
There are two parts to the recommendation of.Regulatory Guide 1.14.
The first part is related to the evaluation of materials of construction, design, fabncation, proof testing; and pre-service inspection of the pump flywheels for construction permit submittals docketed on or after January 1,
1976.
The second part 'is concerned with the evaluation of procedures used for the inservice inspection of pump flywheels for all plants after January 1,
1976.
The regulatory position for the inservice inspection of the reactor pump flywheels for the R. E. Ginna Nuclear Power Plant Unit No.
1 is that the inservice inspection of each flywheel. should be performed in compliance with the recommendations of Section D.2 of Regulatory Guide 1.14 as follows:
A.. In-place volumetric examination of areas of higher stress concentration at approximately 3-year intervals; B.
Surface examination of all exposed.surfaces and a complete volumetric examination at approximately 10-year intervals; C.
The examination procedures should comply with Subarticle IWA-2200 (ASME Section XI);
D.
Acceptance criteria should be that the lowest critical speed is calculated to be twice the normal operating speed; and E.
Should the examination indicate an increase in flaw size greater than predicted.for the service life, the. results should be submitted to the regulatory staff for evaluation.
The integrity of the reactor coolant pump was addressed by the licensee in Section III of the Technical Supplement Accompanying Application for a Full-Term Operating License, August 1972, as follows:
Precautionay measures,.taken to preclude missile formation from primary coolant pump components, assure that the pumps will not produce missiles under any anticipated accident condition.
The primary'coolant pumps run at 1189 rpm,.and may operate
'briefly at overspeeds up to 1091 (1295 rpm) during loss of outside.load.
For conservatism,
- however, 1255 of operating speed.was selected as the design speed for the pr imary coolant pumps.
For the overspeed condition, which would not persist for more than.30
- seconds, pump operating temperatures would remain at about the design value.
Each component of the primary pumps has been analyzed for missile generation.
Any fragments would be contained by the heavy stator.
The same conclusion applies to the impeller because the small fragments that might be ejected would be contained by the heavy casing.
As for the pump motors, the most adverse operating condition of the flywheels is visualized to be, the loss-of-load situatio The following conservative design-operation conditions pre-clude.missile production by the pump flywheels.
The wheels are fabricated from rolled, vacuum-degassed, ASTt1 A-533 steel plates.
Flywheel blanks are flame-cut from the plate, with allowance for exclusion of flame-affected metal.
A minimum of three Charpy tests are made from each plate parallel and normal to the rolling direction, to determine that each bla8k satisfies the design requirements.
An NDTT less than
+10 F is specified.
.The finished flywheels are subjected to lOOX volumetric ultrasonic inspection.
The finished machined bores are also subjected to magnetic particle or liquid penetrant examination.
These design-fabrication techniques yield flywheels with primary stress at operating speed to less than 50Ã of the minimum spegified material yield strength at room temperature (100 to 150 F).
Bursting speed of the flywheels has been calculated on the. basis of Griffith-Irwin's results.to be 3900 rpm, more than three times the operating speed.
A fracture mechanics evaluation was made on the reactor coolant pump flywheel.
This evaluation considered the fol-lowing assumptions:
n.-
a.
Maximum tangential stress at an assumed overspeed of 125/ compared to a maximum expected overspeed of 109Ã.
b.
A through crack through the thickness of the flywheel at the bore.
c.
400 cycles of start up operation in 40 years.
Using critical stress intensity factors and crack growth data attained.on flywheel material, the critical.crack size for failure was greater than 17 inches radially.and the crack growth data was 0.030" to 0.60" per 1000 cycles.
An ultrasonic inspection capable of detecting at least 1/2".
deep cracks from the ends of the flywheel and a dye penetrant or magnetic particle test of the bore both at the end of 10 years will be. more than adequate as part of a plant surveil-lance program.
The design specifications for the reactor coolant pumps include as a design condition the stresses generated by a maximum hypothetical earthquake ground acceleration of 0.2g..
The pump would continue to run unaffect'qd by such conditions.
In no,case does any bearing stress in the pump exceed or even approach a value which the bearing could not carry.
In order to preclude undetected flywheel deterioration during plant life, even though such deterioration is not
- expected, the ultrasonic inspections are repeated at inver-vals during plant life.
Following a hypothetical bearing seizure the flywheel is not
~
- expected to twist off.
Therefore, it has been concluded that the reactor coolant pumps are not sources of.missiles and the engineered safeguards are not in jeopardy.
The Ginna Inservice Inspection Program for the 1980-1989 interval was submitted on. July 2, 1979, in compliance with the requirements of Paragraph (g) of..10 CFR Part 50.
The Inservice Inspection Program for the reactor coolant pump flywheels was dev'eloped to meet the guidance of
~ Regulatory Guide l. 14.
The reactor coolant pump flywheel, listed in Table ISI-l.l of Appendix 8 of the program, will be examined.to the extent.and frequency as recommended in Regulatory Guide 1.14.
The examination will be evaluated to the specified acceptance criteria.
We conclude from our review that the integrity of the flywheels for the reactor coolant pump will be.adequately maintained by an inservice inspection program in compliance with the recommendations of Regulatory Guide 1.14.