ML20010H410
| ML20010H410 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 09/21/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| TASK-03-10.A, TASK-3-10.A, TASK-RR LSO5-81-09-050, LSO5-81-9-50, NUDOCS 8109240433 | |
| Download: ML20010H410 (4) | |
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September 21, 1981 f[fGMib~/h Docket No. 50-213 LS0581- 09-050
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!!r. W. G. Counsil, Vice Pi esident y n gp e l' a 6
Nuclear Engineering and Operations P _. % g Connecticut Yankee Atomic Power Co.
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C Post Office Box 270 iy 4'd A
Hartford, Connecticut 06101 (P
Dear Mr. Counsil:
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SUBJECT:
SEP TOPIC III-10.A, THERMAL-0VERLOAD PROTECTION FOR fl0 TORS OF MOTOR-0PERATED VALVES, SAFETY EVALUATION REPORT FOR HADDMI NECK l
The enclosed staff safety evaluation supplements our contractor's evaluation that has bxn made available to you previously. This evaluation suppc-ts the findinge of the enclosed staff safety evaluation on Topic III-104 that proposes modifications to the valv protective trips.
i The need to actually implement these changes will be determined during tha inf.egrated plant safety assessment. This topic assessment may be revised in the future if your facility design is changed or if HRC criteria relating to this topic are modified before the integrated assessment is completed.
t Sincerely,
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Dennis M.' Crutchfield, Chief i
Operating Reactors Branch No. 5 I
Division of Licensing b o?L G
Enclosure:
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Mr. W. G. Counsil cc Day, Berry & Howerd Counselors at Law One Constitution Plaza Hartford, Connecticut 06103 Superintendtnt Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 Mr. Richard R. Laudenat Manager, Generation Facilities Licensing Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street-Middletown, Connecticut 06457 Board of Selectmen Town Hall H'addam, Connecticut 06103 Ccnnecticut Energy Agency ATTN: Assistant Director Research ano Policy Development Department of Planning and Energy Policy 20 Grand Street Hartford, Connecticut 06106 U. S. Environmental Protection Agency Region I Office ATTN: Regional Radiation Representative JFK Federal Building Boston, Massachusetts 02203 Resident Inspector Haddam Neck Nuclear Power Station c/o U. S. NRC r
East Haddam Post Office East Haddam, Connecticut 06423 l
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ca.r. du %.. _.M.;q g._.gg.g g SYSTEMATIC EVALUATION PROGRAM TOPIC III-10.A HADDAM NECK TOPIC:
III-10. A, THERMAL-0VERLOAD PROTECTION FOR MOTORS OF 'KOTOR-OPERATED VALVES I.
INTRODUCTION The primary objective of thermal overload relays is to protect motor windings of motor-operated volves (MOV) against excessive heating.
This feature of thermal overload relays could, however, interfere with the su'.;essful funnioning of a safety related system.
In nuc-lea'r plant 5;fety systec: application, the ultimate criterior inould -
.be to drive the valve to its proper position to mitigate the conse-quences of an accidents, rather than to be concerned with degradation or failure of the motor due to excessive heating.
.II.
REVIEW CRITERIA The primary review criteria are:
1.
IEEE Std. 279-1971, and i
2.
As a result of r.umerous operating plant events resulting from torque switch problems the folicwir.g supfiemental criterion was used:
"(3) 'In MOV designs that use a torque switch to limit the opening or closing of the valve, the automatic opening or closing signal
- should be used in, conjunction with a corresponding limit switch."
III.
RELATED SAFETY TOPICS AND INTERFACES l
There are no safety areas related to the scope of this review that are l
addressed by other SEP Topics nor are any other topics dependent on l
the results of th,is review.
ll' IV.
REVIEW GUIDELINES l
The review should assure that:
(1) thermal overload protection, if l
provided, for MOV's should have the trip setpoint.at a value high enough to prevent spurious trips due to design inaccuracies, trip set-point drift, or variation in the ambient temperature at the installed location; (2) the circuits th?t bypass the thermal crerload protection under accident conditicns are designed to IEEE Std. 279-1971 criteria, as appropriate for the rest of the safety related system; and (3).in MOV designs that use a torque switch instead of a limit switch to limit the opening or closing of the valve, the automatic opening or closing signal should be used in conjunction with a corresponding limit switch and thermal overload should remain as backup pr:otection
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over.the first 10% of valve trevel.
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. _ _. _. V.
EVALUATION The design provisions for motor-operated valve protecti.. are describeo in ~6&G Report 1669F, " Thermal-0verload Protection for Motors of Motor-Operated Valves." Thermal-overload protection for motor-operated valves at Haddam Neck does not comply with current licensing criteria.
The rmal-overload devices are not bypassed, n.o information is available to support adequacy of trip setpoints, and torque switches rather than limit switches are used to terminate val"s travel.
VI.
CONCLUSIONS
- The Haddam Neck design does not satisfy the current licensing criteria for safety related valve functions.
Because poor valve reliability may lead to the failure of more than one valve during emergency conditions, and multiple valve failures have not been analyzed for their afTect upon system performance and plant safety, the staff recomnends that action should be tak I to improve valve rsliability (i.e., bypassing torque switches with a limit switch during automatic actuation of the valve and bypassing thermal overloads with an ECCS signal).
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