ML20042C337
| ML20042C337 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 03/26/1982 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| TASK-03-10.B, TASK-3-10.B, TASK-RR LSO5-82-03-102, LSO5-82-3-102, NUDOCS 8203310242 | |
| Download: ML20042C337 (7) | |
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4 March 26,1982 C
RECElvgg Docket No. 50-213 2] sama % MAR d
LS05-82 102 nec N
b Mr. W. G. Counsil, Vice President g
Nuclear Engineering and Operations d
Connecticut Yankee Atomic Power Company Post Office Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
SUBJECT:
COMPLETION OF TOPIC III-10.B, PUMP FLYWHEEL INTEGRITY HADDAM NECK PLANT Enclosed is a copy of our final evaluation of Systematic Evaluation Program Topic III-10.B. This report has been revised to reflect the connents con.
tained in your letter of December 9,1980. With this revised evaluation our review of SEP Topic III-10.B is complete and will be a basic input to the integrated assessment of your facility.
Based on our evaluation, we conclude that the flywheel material and design of the pump-motor assembly at Haddam Neck Plant are acceptable and the proposed inservice inspection program will provide the necessary degree of assurance that the structural integrity will be maintained if the goals are realized.
If 100% surface and volumetric examination of the flywheels cannot be performed, this item will be resolved as part of the integrated assessment.
The subject assessment compares your facility design with the criteria cur-rently used by the staff in licensing new facilities.
This assessment may g need to be re-examined if you modify your facility or if the criteria are s
changed before we complete our integrated assessment.
Sincerely, go[y Acol
$.EEo M Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 l
Division of Licensing
Enclosure:
9 As stated
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{ PDR ADOCK 05000213 OFFICIAL RECORD COPY P
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F Mr. W. G. Counsil cc Day, Berry & Howard Counselors at Law i
One Constitution Plaza Hartford, Connecticut 06103 Superintendent Haddam Neck Plant RFD #1 Post' Office Box 127E East Hampton, Connecticut 06424 Mr..Ric'hard R. Laudenat Manager, Generation Facilities Licensing Northeast Utilities Service Company P. O. Box 270 sartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connecticut 06457 Board of Selectmen Town Hall Haddam, Connecticut 06103 State of Connecticut Office of Policy and Management ATTN: Under Secretary Energy Division 80 Washington Street
'Bartford, Connecticut 06115 U. S. Environmental Protection Agency Region 1 Office ATTN: Regional Radiation Representative JFK Federal Building Boston, Massachusetts 02203 Resident Inspector Haddam Neck Nuclear Power Station
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c/o U. S. NRC Easc Haddam Post Office East Haddam, Connecticut 06423 Ronald C. Haynes, Regional Administrator Nuclear Regulatory Commission, Region I Office of Inspection and Enforcement 631 Park Avenue King of Prussia, Pennsylvania 19406
ATTACHMENT CONNECTICUT YANKEE ATOMIC POWER COMPANY HADDAM NECK PLANT SAFETY EVALUATION REPORT MATERIALS ENGINEERING BRANCH DIVISION OF ENGINEERING SEP TOPIC III-10.B - PUMP FLYWHEEL INTEGRITY I.
INTRODUCTION 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.
II.
REVIEW CRITERIA The basis-for review is outlined in Standard Review Plant (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 Nppendix A of 10 CFR Part 50 with regard to minimizing the potential for failures of the flywheels.of the reactor coolant pumps.
III.
RELATED SAFETY TOPICS AND INTERFACES Internally generated missile protection is evaluated ur. der SEP Topic III-4.C.
IV.
REVIEW GUIDELINES There are two parts to the recommendation of Regulatory Guide 1.14.
The first part is related to the evaluation of the materials of construction, design, fabrication, proof testing and pre-service inspection of the
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-2 flywheels. Thesecondpartisconcernedwi(htheevaluation.ofthe procedures.used for the inservice inspection of flywheels.
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~V.
EVALUATION a.
Material and Fabrication
.The disc material is AISI 1020 (processing unknown), which is.
s equivalent to' ASTM A 519 (10_20), low carbon steel.with.a..mi.nimum.. _...
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. yield strength of 37,700 psi and the tensile strength of 63,800 psi.
. The pump flywhe'els are machined from cross rolled blanks and have
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an nil-ductility tiansition reference temperature (RTNDT) of less than higlier than -
40 F; whereas, Reguiatory Guide 1.14 recommends RTNDT n The disc material has an average Charpy energy of 100.ft-lbs' at 20*F.
72*F whereas, the Standard Review Plan requires a room temperature of at least 50 ft-lbs in the " weak" direction (WR)~ at the minimum operating.
s The normal operating temperature of.the Haddam Ndek fly-temperature.
wheels will be approximately 120*F.
The material for the Haddam Neck pump flywh' eel does not explicitly meet the Standard Review Plan requirement for the materials of contstruction and fabrication i_n that the normal operating temperature is 80'F over However, the 80*F temperature differential over RT rather than 100'F.
NDT the operating temperature is considered adequate to ensure upper shelf Since the material is cross rolled,100 ft-lbs behavior of the material.
at 72'F ensures that the toughness will exceed 50 ft-lbs in the " weak."
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direction at minimum operating temperature.
j b.
Design The flywheel, mounted above the motor rotor, provides the inertia necessary to maintain flow for a period to dissipate'the decay heat
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in the core upon the loss of power. At the 6perating speed the bore, tress due' to rotation is 9,900 psi, and at 125 per cent overspeed the bore stress is still less than one half the yield stress.
2 The inertia of the rotating assembly is approximately 45,000 lb-ft,
There are eleven anti-reverse rotation pawls on the periphery of each flywheel and when the flywheel stops, the pawls drop and engage ratchet teeth on a stationary ring.
This prevents reverse rotation and limits the backflow of reactor coolant through the pump.
Regulatory Guide 1.14 requires that the margin against ductile failure relative to the minimum specified yield strength be a factor of 3 and 1.5 at normal operating speed and design overspeed, respectively.
The pump flywheels at Haddan Neck Plant have a margin of safety against ductile fracture and the requirements of the Regulatory Guide 1.14 have been satisfied.
c.
Inservice Inspection Program R69ulatory Guide 1.14 requires that an inservice inspection program e,-
for each flywheel should include the following:
(1)
In-place ' ultrasonic volumetric examination of the areas of higher stress concentration at the bore and keyway at approxi-mately 3 year intervals, during the refueling or maintenance shutdown as required by the ASME Code Section XI.
, (2) A surface examination of all exposed surfaces and complete ultrasonic volumetric examination at approximately 10 year intervals, during plant shutdown coinciding with the inspection schedule as required by the ASME Code Section XI.
The Haddam Neck flywheels do not meet the inspection requirements of the Regulatory Guide 1.14 in that (1) a complete ultrasonic examination of the high stress areas (bore and keyway) cannot currently be performed because of geometry and access problems and (2) the flywheels are painted thereby possibly limiting the ability to perform complete volumetric and surface examinations required during the 10 year intervals. The licensee,
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in their December 9,1980 letter, stated that highly stressed areas of the four flywheels will be examined ultrasonically every three years to the maximum extent possible.
Further, they stated that (1) attempts to improve ultrasonic inspection methods to provide 100% coverage of the bore and keyway areas will be made and (2) 100% surface and volumetric examination of the flywheels cm be met if an acceptable method to remove pa. int can be identified.
VI.
CONCLUSIONS We have reviewed the material, fabrication, design and inspection aspects of the pump flywheels at Haddam Neck plant for compliance with Standard Review Plan 5.4.1.1, We have concluded that the design of the pump-motor assembly in the Haddam Neck plant is acceptable and the proposed inservice inspection program will provide the necessary degree of assurance that its structural in'tegrity will be maintained if the licensee's anticipated goal of 100% surface and volumetric examination of the flywheels during the 10 year intervals is realized.
The licensee should clarify the extent of
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5-inspections that will be performed.
If 100% surface and volumetric examination of the flywheels cannot be performed, this item will be resolved as part of the integrated assessment.
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