ML16161B255
| ML16161B255 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Mcguire, Catawba, McGuire  |
| Issue date: | 10/30/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Parker W DUKE POWER CO. |
| References | |
| 801030, NUDOCS 8012170813 | |
| Download: ML16161B255 (7) | |
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'UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II 101 MARIETTA ST., N.W., SUITE 3100 ATLANTA, GEORGIA 30303 In Reply Refer To:
OCT 30 1980 RII:JPO 50-369 50 50-269 50-270 0-287 50-413 50-414 Duke Power Company ATTN: W. 0. Parker, Jr.
Vice President, Steam Production P. 0. Box 2178 Charlotte, NC 28242 Gentlemen:
This Information Notice is forwarded to provide a notification of a potential source of degradation that might occur in a safety-related component over long-term operation. No specific action or written response to this Information Notice is required at this time.
If you have any questions related to this matter, please contact this office.
Sincerely, James P. O'Reilly Director
Enclosures:
- 1.
IE Information Notice No. 80-38 w/Enclosure
- 2.
List of Recently Issued IE Information Notices cc w/encl:
M. D. McIntosh, Plant Manager J. C. Rogers, Project Manager J. E. Smith, Station Manager J. W. Hampton, Station Manager D. G. Beam, Project Manager 0i~ 2'I3 P
SSINS No.:
6835 Accession No.:
UNITED STATES 8008220180 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 October 30, 1980 IE Information Notice No. 80-38:
CRACKING IN CHARGING PUMP CASING CLADDING Description of Circumstances:
In January 1980 Commonwealth Edison Company (CECo) reported to the NRC that a radiographic examination had revealed crack indications in the cladding on the suction end plate of the 1A charging pump at Zion Unit 1. This cen trifugal charging pump 1A is one of two pumps installed in Zion Unit 1 for, high-head safety injection of borated water to the reactor loops. These pumps are additionally utilized as charging pumps during normal operation. ASME Section XI inservice inspection rules referenced in the plant technical specification requires pump examination only once during the 10 year service interval and this pump had been in service about 7 years.
The pumps are 2-1/2 inch, 11 stage, Type IJ manufactured by the Pacific Pumps Division of Dresser Industries. The pump casing end assembly in the area of interest, Figure 1, consists of a suction end plate of A515 grade 60 carbon steel plate welded to the casing barrel forging of A266 class 1 carbon steel using an Inconel weldment. The entire inner surface is clad with type 308 stainless steel applied by submerged arc welding.
An in-situ ultrasonic examination conducted in late April confirmed clad cracking indications at the barrel case to end plate inner radius for approximately 330 degrees around the circumference and that the cracking possibly extended into the pump base material in the bottom 180 degrees of the assembly. A review of the original radiographs revealed crack like indications in the clad overlay, however, not to the extent observed during this examination.
Subsequently, the entire suction end of the pump was removed and cross sections metallographically examined to further evaluate the nature and extent of the cracking.
It was determined that initiation and propagation of the clad cracks probably resulted from stress concentration and dilution effects in the initial corner bead pass due to the difficult access and bead sequencing required by the fairly sharp corner geometry. Extension of the cracks at the base metal clad interface ranged to a depth of 1/16 inch maximum in the 1-1/2 inch thick base material.
These crack tip areas were well blunted and slightly cavitated from corrosion effects due lengthy exposure to the localized boric acid attack.
Examination of the crack morphology revealed that the clad cracking essentially arrested at the base metal-clad interface and that base metal corrosion progres sed at a relatively slow rate.
The 1A charging pump was replaced with a new pump provided with a casing con structed entirely of stainless steel. The licensee is currently developing improved NDE procedures for examination of the three remaining pumps at the next refueling outage. Further, the licensee and pump manufacturer are developing repair procedures in the event cracks are discovered in the remaining pumps.
SSINS No.:
6830 Accession No.:
8008220280 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.. 20555 January 23, 1981 IE CIRCULAR NO. 8!-01:
DESIGN PROBLEMS INVOLVING INDICATING PUSHBUTTON SWITCHES MANUFACTURED BY HONEYWELL INCORPORATED
Background:
By letter dated September 18, 1980 (J. M. Curran to R. H. Engelken), Southern California Edison Company (SCE).notified NRC of design problems involving certain indicating pushbutton switches. The.subject switches are of the type designated as Series.2 indicating pushbutton switches that are manufactured by the Micro Switch Division of Honeywell Incorporated. The switches identified by SCE. as having.design deficiencies are used on the containment isolation panels at San Onofre Unit.l.(Docket No.. 50-206).
SCE identified two problems with the subject switches, both of which manifest, themselves duringrelamping,:- (1) a. short circuit. may be induced;. and (2) the circuit controlled by the switch may inadvertently be actuated. Although the specificity of this circular is restricted to the previously mentioned:Series 2 switches the.deficiencies cited. may be commdn to other-indicating pushbuttorr switches. Accordingly,.holders of operating licenses and construction permits.
should scrutinize the design of other indicating pushbutton switches--in their facilitiesfor susceptiblity to the above-problems:.
By letter dated-October 10, 1980 (J. G. Haynes-toR. H. Engelken), SCE submitted a detailed followup report addressing the defective switches. Sections of the SCE report containing relevant information have been excerpted and included in the paragraphs that follow. Sections so.excerpted are identified.by quotation marks-..
Discussion:
The SCE report provided the following.details of the-problems previously mentioned:
"I., The design of indicating pushbutton switches is such that during insertion of the lamp assembly into-the switch housing,.shorting could occur betweent-the metallic plunger and the energized indicator lamp-connection insidethe switch assembly. Since the metal plunger is connected to-the cabinet ground through the switch housing, the control circuit could be short circuited, causing, failure of the control circuit if it is energized.
' EC No. 81-01 January 23, 1981 Page 2 of 4
- 2.
The design of the lamp assembly is such that to lock the switch into place after relamping will cause actuation of the switch resulting in operation of the control circuit if it is energized. Since the current containment isolation system operational design requires that the power supply to the containment isolation panels remain energized during relamping, the potential exists for operating containment isolation valves during the-lamp replacement."
To circumvent the preceding problems, SCE, in cooperation with Honeywell Incorporated, is implementing the following corrective actions.
"1. The metallic plunger is being redesigned to solve the short circuit problem discussed in Item 1 above. The design modification involves providing a plastic tip on the plunger. The plastic tip will provide isolation between the metallic plunger and energized indicator lamp connection inside the switch assembly and this will avoid short circuit problems. A-prototype modified switch assembly was received on September 20, 1980 and successfully tested. Accordingly, the manufacturer is developing the necessary tooling for production, purposes.
It is expected that the modified switch assemblies can be delivered and. installed prior to return to power operation from the current. outage..
- 2.
The indicating pushbutton lamp assembly system is being redesigned to solve the switch actuation problem discussed in Item 2. above.
The design modification wilr permit relamping with the power supply energized, without causing switch actuation. It is expected that the-system. will be redesigned and the current switches replaced during the next scheduled cold shutdown of sufficient duration following return to power operationfrom the-current outage-."
In addition, SCE.has instructed its.station personnel on procedural steps to be followed when changing lamps.
The procedural steps currently in effect at San Onofre Unit 1.for relamping the indicating push button switches address the potential for shortingor for inadvertently actuating the control circuitas follows:
"1. Containment Isolation Valves on Non-essential Systems All automatic containment isolation.valves are-included in this category-. When replacement of a.burned out.lamp is necessary,.the power supply of the circuit of the valve will be opened and-the associated, valve will. close if open or will be de-energized in.the closed position.if already closed.. The burned out lamp will be replaced and the power supply to the circuit will be closed permitting the valve to be reopened-or re-energized in the closed position.
- 2.
RemoteManual Containment Isolation Valves on Essential Systems The systems in.this category include the Chemical Volume and Control Letdown System, Reactor Coolant Pump Seal Water Return System, Turbine Plant Cooling Water Supply and Return System, and Pressurizer Relief
IEC No. 81-01 January 23, 1981 Page-3 of 4 Tank Nitrogen Supply System-., The containment isolation valves on these systems are normally open during operation and may be required to be open during accident conditions.
If it is necessary to replace burned out lamps after the metallic plunger has been redesigned as described in corrective action 1 above, the following steps will be:taken:
- 1.
The touch plate with the burned out lamp will be removed and lamps replaced.
- 2.
The glass. cover on the HFA relay (panels behind north vertical board) associated with the valve in question will be removed and the relay held in place by depressing the insulated portion of the spring loaded relay plunger.
- 3.
The touch plate with the replaced lamps will be inserted into the switch chassis.
- 4.
The "open" switch of the valve in question will be depressed to assure that the circuit has been reset and the glass cover replaced on the HFA relay."
"If. it is necessary to replace burned out lamps before the metallic plun--.
ger is redesigned, the-replacement will be performed-during-an outage of sufficientduration when' the affected'system and'valve can be removed from service. At that time,. the procedural steps to be followed are identical to those established for the automatic-containment isolation valves on non essential systems.discussed above. Until such timeas the:lamp can be re placed, the position of the affected valve can be. determined by examining the-system flow, pressure:and temperature process-instrumentation."
Recommended Actions for Holders-of Construction-Permits or Operating Licenses:
1..
Determine whether your facility uses-the subject Series-2 indicating push button. switches in any-safety-related function. If there are no indicating pushbutton switches of this type in your facility, you need not pursue this matter further.
- 2.
If the subject switches are used to perform safety-related functions at your facility, either replace them with qualified units or modify them to eliminate the deficiencies. Holders of operating licenses-should take the appropriate action as soon as practical; construction permit holders should take the appropriate action prior to startup.
(If the switches are to be modified, contact Honeywell Incorporated for assistance-.)
- 3.
UntiL the appropriate corrective action is completed, the followinginterim measures should be taken:
IECNo.81-01 January 23, 1981.
Page 4 of 4
- a.
If the design of the affected equipment permits its switch assembly to be deenergized.for relamping, verify that the procedures specify that power is to be removed from the switch assembly during relamping. If the procedures do not so specify, revise them to includesuch a provision.
- b.
If the design of-the affected equipment does not permit its switch assembly to be deenergized for relamping, verify that the operator can determine the status of the affected equipment by alternate.
means. Towards this end, implement procedures to enable the operator to determinethe status of the affected equipment by alternate means (e.g., acceptable method for inferring the position of a valve.could include system flow, pressure, or temperature measurements).
If alternate status indication methods are not available, relamping should be deferred until the next outage during which time the affected equipment can be removed from service. However, during the resulting blind time,.rigid. administrative controls should be implemented to provide the operator with reliable status information.
No written response to this circular is required.
If you require additional information with regard to. this subject, please contact the appropriate NRC Regional Office.
IEC 81-01 January 23,.1981 RECENTLY ISSUED IE CIRCULARS Circular Date of No.
Subject Issue Issued to 81-01 Design Problems Involving 01/23/81 All nuclear power Indicating Pushbutton Switches.
facilities holding Manufactured by Honeywell an OL or CP Incorporated 80-25 Case-Histories of 12/5/80 All radiography Radiography Events licensees 80-24 AECL Teletherapy Unit 12/2/80 All teletherapy Malfunction licensees 80-23 Potential Defects in Beloit 10/31/80 All power reactor Power Systems Emergency facilities with Generators OL or a CP 80-22 Confirmation of Employee 10/2/80 All holders of a.
Qualifications power reactor OL or CP architect-engineering companies and nuclear steam system suppliers; 80-21 Regulation of Refueling 9/10/80 All holders of a Crews power-reactor OL or CP 80 Changes, in Safe-Slab Tank 8/21/80 All Part 50 and Part Dimensions-70 fuel facility licensees 80-19 Noncompliance with 8/26/80 All medical licensees License Requirements for Medical Licensees 80-18 10 CFR 50.59 Safety 8/22/80 All power reactor Evaluations for Changes-to facilities with an Radioactive Waste Treatment OL or-CP Systems.
80-17 Fuel Pin Damage Due to Water 7/23/80 All holders of PWR Jet from-Baffle Plate Corner OLs and PWR CPs 80-16 Operational Deficiencies In, 6/27/80 All power reactor Rosemount Model 510DU Trip-facilities-with an Units And Model 1152 Pressure OL or a CP Transmitters Cooling and Natural Circula-facilities with an tion Cooldown OL or CP OL= Operating Licenses CP = Construction Permit