ML19329E366
| ML19329E366 | |
| Person / Time | |
|---|---|
| Site: | Midland |
| Issue date: | 07/26/1978 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Howell S CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| References | |
| NUDOCS 8006120677 | |
| Download: ML19329E366 (1) | |
Text
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,,3 JUL 2 61978 Docket No. 50-329 Docket No. 50-330 Consumers Power Company ATIN: Mr. Stephen H. Howell Vice President 1945 West Parnall Road Jackson, MI 49201 Gentlemen:
i The enclosed IE Circular No. 78-16 is forwarded to you for information.
If there are any questions related to your understanding of the suggested actions, please contact this office.
l Sincerely, James G. Kepplcr Director
Enclosures:
1.
IE Circular No. 78-16 2.
List of IE Circulars Issued in 1978 THIS DOCUMENT CONTAINS cc w/encia:
POOR QUAUTY PAGES LAufntral Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Ronald Callen, Michigan Public Service Commiasion Dr. Wayne E. North 8006 120 h hh g
Myron M. Cherry, Chicago orrlec k RIII RIII suRwawe >.
Il er 7-26-78 7-26-78 OATE>
NRC Form 318A (R3II) (5-76) NRCM 02040
.u. S. GOVERNMENT PRINTING OFFICE: 1978-253 818 N
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U.S. NUCLEAR REGULATORY COMMISSION O'? ICE OF INSPECTION AND ENFORCEMENT REGION III July 26, 1978 IE Circular No. 78-16 LIMITORQUE VALVE ACTUATORS Description of Circumstances:
At Rancio Seco, a Limitorque Type SMB-2 motor-driven valve actuator in a sat.~ety feature system failed to function. The failure resulted from c'.utch wear which was due to manual operation of the valve and i
improfer heat treatment of the clutch parts. Other SM3 valve actua-tets at Rancho Seco had been subjected to undue clutch wear but ve.re still operable. Based on information obtained from the licensee and from Limitorque Corporation, undue wear appears to be limited to Type SMB-0, 1, 2, and 3 valve actuators equipped with 3600 rpm motors.
The type SMB valve actuator is provided with a handwheel so that the valve can be actuated manually in the event that power is unavailable.
To shift from motor drive to handwheel drive, the operator must manually position a clutch so that the motor is disengaged from tha drive train and the handwheel is engaged. The clutch latches into this position and cannot be manually repositioned. The next time that the motor is energized, the latch releases automatically and a spring repositions the clutch so that the motor engages the drive train.
When the clutch is repositioned, a pair of lugs on the motor-side of
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the clutch engages a pair of lugs on the valve-side. At the instant the lugs engage, the lugs on the motor-side are being accelerated to full speed and the lugs on the valve-side are stationary. Before the i
motor is energized, the relative position of the lugs is random. This initial position determines the depth of engagement or bite at the instant the lugs make contact. When a full bite occurs, no damage is caused to the lugs. When a grazing bite occurs, the edges of the lugs are chipped or upset. After the edges are sufficiently rounded, the clutch will not engage and hold for motor actuation.
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IE Circular No. 78-16 July 26, 1978 The licensee estimated that the failure of the Type SM3-2 valve actuator occurred after it had been clutched 25 to 100 times. The valve which failed to function at Rancho Seco (SFV-25003) is operated by the actuator and is a safety features valve in a line connecting the borated water storage tank to a high prescure safety injection pump and a decay heat removal (low head safety injection) pump. The valve actuator is wired so that the valve which it controls will drive to the fully open or fully closed position once the motor is energized.
SFV-25003 is used for various routine operations during refueling, e.g.
adding borated water to the primary cooling system. In these instances, the operator uses SFV-25003 as a throttle valve. To do this, the valve must be actuated manually, giving rise to the potential damage to the lugs as described above. This would not occur with the type of valve actuator that is clutched with the motor at rest. Likewise, a separate throttle valve for supplying borated water during routine operation would preclude the need for manual operation of the subject valve actuator.
Limitorque Corporation has a test program in progress for determining the clutch life of Type S23. O,1, 2, and 3 valve actuators. Results to date are inconclusive. Pending other resolution of the problem, the licensee has stated that the valve will be stroked with the motor drive to ensure that the clutch has engaged the motor following manual actuation of the valve.
All licensee and construction permit holders should consider:
For Limitorque Type SMB-0, 1, 2, and 3 valve actuators with 3600 rpm motors which are used or will be used in engineered safety systems;
- 1) The potential for failure of the actuators resulting from manual operation,
- 2) Means for minimizing manual operation and,
- 3) Procedures for verifying that the actuator is operable with the motor af ter manual operation.
No written response to this Circular is required. If you require additional information regarding this matter, contact the Director of the appropriate NRC Regional Office.
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IE Circular No. 78-16 July 26, 1978 LISTING OF IE CIRCULARS ISSUED IN 1978 Circular Subj ect Date Issued To No.
of Issue 78-01 Loss of Well Logging 4/5/78 All Holders of Source Well Logging Source Licenses 76-02 Proper Lubricating 011 4/20/78 All Holders of for Terry Turbines Reactor OLs or cps 78-03 Packaging Greater Than 5/12/78 All Holders of Type A Quantities of Reactor OLs, cps, Low Specific Activity Fuel Cycle, Radioactive Material Priority I Material for Transport and Waste Disposal Licenses 78-04 Installation Error That 5/15/78 All Holders of Could Prevent Closing of Reactor OLs or Fire Doors cps
,v-05 Inadvertent Safety Injection 5/23/78 All Holders of During Cooldown Reactor OLs or cps 78-06 Potential Common Mode 5/23/78 All Holders of Flooding of ECCS Equipment Reactor OLs or I
Rooms at BWR Facilities cps 1
73-07 Damaged Components of a 5/31/78 All Holders of Bergen-Paterson Series Reactor OLs or 25000 Hydraulic Test cps Stand 78-08 Environmental Qualification 5/31/78 All Holders of of Safety Related Equipment Reactor OLs or at Nuclear Power Plants cps 78-09 Arcing of General Electric 6/5/78 All Holders of Company Size 2 Contactors cps Enclosure Page 1 of 1 A
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IE Circular No. 78-16 July 26, 1978 LISTING OF IE CIRCULARS ISSUED IN 1978 Circular Subject Date of Issued to No.
Issue 78-10 Control of Sealed 6/14/78 All Medical Sources Used in Licensees in Radiation Therapy Categories G and G1 I
73-11 Recirculation M-G 6/15/78 All Holders of
. Set Overspeed Stops BWR OLs or cps 78-12 HPCI Turbine Control 6/30/78 All Holders of Valve Lift Rod Bending BWR OLs or cps for plants with HPCI Terry Turbine 78-13 Inoperability of Multiple 7/10/78 All Holders of Service Water Pumps Reactor OLs and cps except for plants located in: AL, AK, CA, FL, GA, LA, MS, SC l
78-14 HPCI Turbine Reversing 7/12/78 All Holders of BWR Chamber Hold Down Bolting OLs or cps for plants with a EPCI Terry Turbine excepting Duane Arnold and Monticello 78-15 Checkvalves Fail to 7/20/78 All Holders of Close In Vertical Reactor OLs or cps Position j
i Enclosure Page 2 of 2 i
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