ML20101G394
| ML20101G394 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 12/12/1984 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Kirsch D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| ANPP-31452-TDS, DER-84-54, NUDOCS 8412270495 | |
| Download: ML20101G394 (6) | |
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Arizona Nuclear Power Project
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December 12, 1984 YC:q i'.
L. S. Nuclear Regulatory Commission Region V-1450 Maria Lane - Suite 210 Walnut Creek, California 94596-5368 Attention: Mr. D. F. Kirsch, Acting Director Division of Reactor Safety and Projects,
Subject:
Final Report - DER 84-54 i
A 50.55(e) Reportable Condition Relati:tg To Containment Sump Isolation Valve.
File: 84-019-026; D.4.33.2
Reference:
A) Telephone Conversation between P. Narbut and T. Bradish on August 17, 1984 B) ANPP-30543, dated September 17, 1984 (Interim Report)
C) ANPP-30871, dated October 17, 1984 (Time Extension)
D) ANPP-31000, dated October 30, 1984 (Time Extension)
E) ANPP-31153, dated November 15, 1984 (Time Extension)
F) ANPP-31263, dated November 30, 1984 (Time Extension)
Dear Sir:
Attached is our final written report of the Reportable Deficiency under i
10CFR50.55(e) referenced above.
Very truly yours,
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Cf.JUL E. E. Van Brunt, Jr.
APS Vice President Nuclear Production i
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AFPP Project Director 3
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. Richard DeYoung, Director
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.U.:S. Nuclear Regulatory Commission
. Washington, D. C.: 20555.
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.1100 Circle 75 Parkway, Suite 1500 Atlanta, GA '30339 l
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m FINAL REPORT - DER 84-54 DEFICIENCY EVALUATION 50.55(e)
ARIZONA PUBLIC SERVICE COMPANY (APS)
PVNGS UNIT'1
' I.
Description of Deficiency.
Containment sump isolation valve 1JSIAUV673 could not be opened electrically after being manually closed.
The valve operates correctly when not closed manually. This condition was identified during preoperational testing and documented on SFR 1SI-723 and NCR--SM-4609.
Valves 1JSIAUV674, 1JSIBUV675, and 1JSIBUV676 are similar valves that perform the same function as the subject valve. They are 24 inch,-
limitorque motor operated butterfly valves, manufactured by Posi Seal International and supplied by Combustion Engineering. These valves are required.to open automatically on a recirculation actuation signal (RAS) to provide a suction source for the safety injection pumps. A RAS is initiated on low water level in the refueling water tank during safety injection (reference CESSAR Sections 5.3.2.2.3 and 5.3.5.2).
Evaluation Two factors have been identified as potentially contributing to this deficiency: 1) a design problem in the motor operator, and 2) high packing friction.
1.
The first factor deals with a design aspect of the Limitorque operators. The operators on these valves (Limitorque Model H2BC SMB-00-10) use rotors to open and close contacts as required for l
position indication, torque switch bypass, open limit and closed limit. These operators were supplied with the closed portion contacts and the torque switch bypass contacts on the same rotor. This rotor is set such that when the valve disc reaches the closed position (zero degrees), the closed limit contacts trip and stops the motor.
Since the torque switch bypass contacts are on the same rotor, they cannot be adjusted independently of the closed position contacts so they also trip at zero degrees. In effect, torque switch bypass only. occurs from the valve mechanical stop position'to the zero degree position.
l 2.
The second factor, high packing friction, may result from l_
modifications'made to the valve packing boxes. The original nacking configuration utilized a lantern ring and asbestos type packing. Based on a project decision that applied to all valves at PVNGS, the lantern rings were eliminated and the valves were packed with a grafoil type packing.
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Final Report 1 DER 84-54 Page Two After closing the valve electrially,: the torque switch' allows for enough torque to' overcome-the opening resistive forces within the valve and operator and'the additional packing friction discussed above. Since the torque switch has this capacity,-torque switch bypass is not required and the valva operates correctly. However, when the valve is closed manually, the disc is driven past the zero degree position to the mechanical stop. The torque required to open the valve from this position is greater than from the zero degree C
position (see sketch). This-torque exceeds.the capacity of the torque switch so bypass is required.
".awever, as discussed above, the bypass trips at zero degrees.- Therefore, the active torque switch trips the motor on an overtorque condition.
The action to preclude recurrence of this problem is to use one of-the spare rotors in the operator for the torque switch bypass. This will allow for adjustment of.the rotor such that the torque switch is bypassed beyond the zero degree position.
This condition has been determined to apply to the four valves listed in Section I along with the same valves for Units 2 and 3 and to the valves listed below which are Posi Seal butterfly valves of the same design:
1, 2, 3JSIAHV657 (16 inch) 1, 2, 3JSIBHV658 (16 inch) 1, 2, 3JSIAHV678 (10 inch) 1, 2, 3JSIBHV679 (10 inch)
II.
Analysis of Safety Implicatons i
Based on the above, this condition is evaluated as reportable under the requirements of 10CFR50.55(e); since, if this condition were to remain uncorrected, it could represent a significant safety condition.
This project also has evaluated this condition as reportable under 10CFR21, 21(b)(3). This report addresses-the reporting requirements of the regulation with the exception of subpart (vi), regarding the number and location of such components supplied to other facilities.
4 III.
Corrective Action NCR SM-4609 has been dispositioned.to rework the operators to use a different rotor (spare rotor 4) for the torque bypass. DCPs'1SE, 2SE, and 3CE-SI-500 have been issued to complete this work on all four valves per unit identified in Section I and the additional four i
valves per unit identified above. This work has been completed in Unit 1 and will be completed prior to operating license in Units 2 and 3.
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-i Final Report DER 84-54 Page Three No action is required with respect'to packing since the above modification will allow enough torque to overcome some excessive packing friction.
IV.
References Letter V-CE-31004,-September 25, 1984 Letter V-CE-31513, December 6,-1984 f
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CONTACT VALVE POSITION OPEN CLOSED (90')
(0*)
TORQUE SWITCH BYPASS
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CONTACT OPEN CONTACT CLOSED CLOSED LIMIT MECHANICAL STOP POSITION r
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TORQUE SWITCH AFTER MANUAL COMPARISON OF CAPACITY
_ _ _ h - CLOSURE TORQUES REQUIRED TO OPEN AFTER ELECTRICAL (NOT TO SCALE)
CLOSURE-
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