ML20074A739
| ML20074A739 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 04/11/1983 |
| From: | William Jones OMAHA PUBLIC POWER DISTRICT |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| LIC-83-120, NUDOCS 8305160027 | |
| Download: ML20074A739 (10) | |
Text
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l Omaha Pubile Power District 1623 Hamey Omaha Nebraska 68102 402/536-4000 May 11, 1983 LIC-83-120 Mr. Robert A.
Clark, Chief U.
S.
Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of Licensing Operating Reactors Branch No. 3 Washington, D.C.
20555
Reference:
Docket No. 50-285
Dear Mr. Clark:
Environrt. ental Qualification of Safety Related Electrical Equipment in a Harsh Environment The District received the Commission's letter dated April 4, 1983 which provided clarification to the electrical equip-ment qualification Safety Evaluation Report (SER).
As re-quested, the District has reviewed its 30-day response to the Commission's SER (OPPD letter dated February 16, 1983).
{
This review identified 3 items requiring additional re-sponses.
Attached is the District's justification for continued operation for the following items:
(1)
Fisher 546 E/P Valve Positioner (2)
Pyrotrol III Cable (3)
Limitorque Valve Motor Brake Sin
- ely, 4.
. M Divis n Manager ing N
Produ ion Operations 38 go WCJ/TLP:jmm Qf Attachment og i
I Sa cc:
LeBoeuf, Lamb, Leiby & MacRae l
g4 1333 New Hampshire Avenue, N.W.
og Washington, D.C.
20036 co n.a.
Mr.
L.
A.
Yandell, Senior Resident Inspector 45.5124 Employment with Equal Opportunity l
Male / FOT idle
r-Attachment ITEM 1 FISHER MODEL 546 E/P TRANSDUCER TER Equipment Item No.:
84 NRC Qualification Category:
IV ( Documentation Not Made Available)
Justification for continued operation is not necessary be-cause Fisher Model 546 E/P transducers are fully qualified for the environmental conditions encountered at Fort Calhoun.
The qualification documentation is on file and the SCEW sheets were revised to reflect the new documentation.
This equipment should be reclassified to Category I.a.
(equipment qualified).
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. ITEM 2.a.
PYROTROL III CABLE TER Equipment Item Nos.:
85, 87, 88, and 89 NRC Qualification Category:
II.a. (Equipment Qualification Not Established)
Subject:
Instrumentation Cable (W57, W59)
Power Cable (W10)
Power Cable (W14, W16, W17, W18, W19, W21)
Control Cable (W37, W38, W39, W40, W41, W42)
Pages:
6-55, 6-58A, 6-57, 6-56 Deficiency: Aging Degradation Evaluation, Qualified Life or Replacement Schedule, Radiation Criteria Justification for continued operation has already been pro-vided for these items.
(NOTE:
FRC did not find a lack of justification for continued operation in the TER.)
lioweve r,
in light of the deficiencies noted in the TER, the District feels that additional information on these items is war-ranted.
The TER concluded that the documentation submitted for the Rockbestos (Cerro) Pyrotrol III cable is insufficient to satisfy the DOR Guidelines in the areas of qualified life, age related degradation, and radiation.
Specifically, the case for the similarity between Pyrotrol III and the Fire-wall III cable (which has been fully qualified) was not felt to be adequately demonstrated because the chemical composi-tion and the manufacturing process of the Pyrotrol III cable has not been shown to be the same as for the Firewall III l
cable.
l Due to the qualification deficiencies noted in the TER, the l
District has attempted to locate additional qualification data for Pyrotrol III cable.
Tfo Franklin Institute Re-search Laboratories (FIRL) techr;ical reports have been obtained which establish radiat'.on dose qualifications for Pyrotrol III cable that envelope the requirements for the auxiliary building and the reactor containment (i.e., 7MRads l
and 30MRads, respectively).
The FIRL reports are as fol-t lows:
F-C2404-01 Test of Electrical Cables Under Simulated Post-Accident Reactor Containment Service, June 1969 l
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. ITEM 2.a.
PYROTROL III CABLE (Continued)
F-C2357 Test of Electrical Cables Under Simulated Post-Accident Reactor Containment Service, September 1970 The District has expended considerable effort in attempting to obtain information and establish aging qualifications for the Pyrotrol III cable.
These efforts continue on three fronts:
1.
Trying to establish that the chemical composition and manufacturing process of the Pyrotrol III cable are equivalent to the Firewall III cable.
2.
Considering establishment of a test program (presently being developed by Rockbestos).
3.
Considering implementation of a surveillance program.
The Listrict expects that the aging qualification of the Pyrotrol III cables will be resolved using one or more of the above methods by the end of the 1984 refueling outage.
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ITEM 2.b.
- TER Equipment Item No.: 86 NRC Qualification Category:
II.c.
Subject:
Component Cooling Water Pump Power Cable (Wll)
Page:
6-58B Deficiency: Aging Degradation Evaluation, Qualified Life or Replacccant Schedule See the discussion for TER Equipment Item Nos. 85, 87, 88, and 89 which is applicable to this cable, except for the portion which relates to radiation.
(No deficiencies were identified for radiation qualifications of this cable.)
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. ITEM 3 LIMITORQUE VALVE MOTOR BRAKES TER Equipment Item No.: 28 Motor Brakes for Feedwater Isolation Valves HCV-1385 and HCV-1386 The TER noted that certain information concerning the motor brake assemblies to HCV-1385 and HCV-1386 was not provided.
The motor brakes provided with the main feedwater isolation valves HCV-1385, HCV-1386, and backup isolation valves HCV-1103 and 1104 (Limitorque motor operators) were manu-factured by Dings Company, division of Wehr Corporation in Milwaukee, Wisconsin.
The brakes are electrically operated disc brakes, energized to disengage and described as fol-lows:
Model:
R72035-4 Voltage:
460 volt, single phase Insulation:
Class B
Enclosure:
Dust tight - watertight Manufacturer:
Dings Company Dynamic & Magnetic Group Division of Wehr Corporation 4740 West Electric Avenue Milwaukee, Wisconsin 53219 The brakes are electrically connected in parallel to one phase of the operator motor.
The brake is energized (dis-engaged) whenever the motor is energized, allowing the motor to turn freely.
The two failure modes of the brake coils, either open or short circuit, would prohibit operation of the valve.
Environment All four valves are located in the mechanical penetration room 81 and will be subjected to the following environments:
Normal Temperature:
400F to 1220F Humidity:
15 to 95%
Radiation:
Neglig ib le Pressure:
Atmospheric l
. ITEM 3 L1dITORQUE VALVE MOTOR BRAKES (Continued)
Accident (main steam line break)
Temperature:
2160F l
Humidity:
100% condensing Radiation:
103 rads Pressure:
1.2 psi Isolation valves HCV-1385, HCV-1386, HCV-1103, and HCV-1104 would be expected to operate (close) under the accident conditions.
Discussion All mechanical parts of the brakes are composed of either cast or cold rolled steel which will not show degradation under the environmental conditions in room 81.
Electrical components are limited to eight (8) 460 volt coils which disengage the brake when energized.
A material list for the coils has been obtained from Dings Company and that list is reprinted as follows with the environmental resistance of each item:
DINGS DYNAMICS & MAGNETIC GROUPS H20003 Class B insulated coils in the R72035-4 electric brake IT Description Material Environmental Resistance 1
Magnetic Wire Copper Characteristics of cop-per are not appreciably affected by radiation er temperature levels seen in room 81.
2 Cross Over Permacel Temperature:
2000F Insulation
- 243 GAMMA:
1 x 105 RAD Tape Aging:
The polyester Polyester materials show the least Film /
resistance to aging con-Polyester ditions.
Exposure to Matt 105 _ 106 RAD will cause the polyester tensil and impact stren th to de-crease at 10
- 108 ergs 9-1 At these levels, its usefulness as an insulator could be de-graded due to cracking.
o
. ITEM 3 LIMITORQUE VALVE MOTOR BRAKES (Continued)
IT Description Material Environmental Resistance Polyester sho'ws a 20% de-crease in strength after exposure to 1000C temper-ature for 170 hours0.00197 days <br />0.0472 hours <br />2.810847e-4 weeks <br />6.4685e-5 months <br /> which could cause de-gradation due to crack-ing.
It should be noted that both these 1 vels are far in excess of normal or accident con-ditions.
3 Construction Permacel See Item 2.
Tape 6243 Tape Polyester Film /
Polyester Matt 4
Leadwire NOMEX-M Temperature:
1670F Insulation Nylon &
(nylon)
Mica Paper GAMMA:
8.6 x 104 RAD (nylon)
Aging:
Mica will not undergo any discernible degradation due to accident environmental parameters seen in room 81.
5 Core Liner NOMEX-M See Item 4.
Nylon &
Mica 6
Anchor Tape Pe rmacel See Item 2.
- 243 Polyester Film /
Polyester Matt
. ITEM 3 LIMITORQUE VALVE MOTOR BRAKES (Continued)
))
Description Material Environmental Resistance 7
Leadwire Copper Wire Temperature:
2560F TPE Insul-GAMMA:
The radiation ation resistance for Styrene (Thermo Butadiene rubber is 2x Plastic 106 RAD.
TPE insulation Elastimer) system is a Styrene block copolymer and as such has the same radiation resistance.
8 Part No. Label NOMEX Nonessential element -
See IT 4.
9 Outerwrap Fiberglass Temperature:
4800F GAMMA:
1x 104 RAD 10 Finish Coat 1300C Var-Temperature:
2660F nish GAMMA:
1x 10 5 RAD Dolth PC 346A Varnish is mineral filled Polyester and used as a final Based finish to give the coil an integrated temper-ature rating of 1300C (2660F).
The Dings Company states that the integrated temperature rating of the entire coil assembly meets the requirements as NEMA Class B insulation rated for 800C temperature rise over a 400C ambient.
I should be noted that most of the materials comprising the insulation system show maximum temperature less than the 1300C (2660F) maximum temperature for a Class B system.
However, the Class B requirements have been met by testing the complete insulation system per the NEMA standards for Class B insulation.
The integrated radiation dose limit for the brakes is 104 RAD as determined by the threshold level of nylon used for leadwire insulation and core liners.
Conclusion The Dings Company brakes used on feedwater isolation valves HCV-1385 and HCV-1386, HCV-1103, and HCV-1104 are a standard l
industrial general purpose brake.
Continued use of these brakes can be justitied in the mild environment of room 81.
.... ITEM 3 LIMITORQUE VALVE MOTOR BRAKES (Continued)
The brakes are only energized during valve operat'.on which is a short period of time occurring infrequently throughout the life of the plant.
It is therefore a reasonable as-sumption that the brake coils are subjected to only ambient temperatures throughout their lifetime and should have a qualified life consistent with the Class B insulated motor provided with the Limitorque operators.
During a main steam line break incident, the brakes would be required to operate once immediately after detection of the leak.
Since the brakes are housed in a watertight cast-iron enclosure, the coils will be protected from condensing steam.
The combination of the short operating period and the immediacy of their operation should prevent the coils from exceeding the 1300C (2660F) maximum temperature limit-ation.
Subsequent failure of the brakes after the isolation operation will be of no consequence to obtaining a safe shutdown condition after the main steam line break.
The low radiation threshold of some of the insulating material poses no problem in the mild radiation environment of room 81.
The Dings Company Model R72035-4 brakes provided with the motorized valve operators on feedwater isolation valves HCV-1385, HCV-1386, HCV-1103, and HCV-1104 will be replaced during the 1984 refueling outage with brakes manufactured for use in nuclear power plants.
The general duty brakes currently installed on the valve operators appear to be adequate for use in the mild environment of room 81 based on the material analysis of the degradable electrical com-ponents.
However, acceptable operation under the design basis accident conditions has not been demonstrated by testing and no aging analysis has been performed.
There-fore, the brakes should be replaced with a Dings Model 6-72035-6 brake.
Although the brake manufacturer does not have a qualification program for these brakes, Limitorque has tested the valve operator / brake combination.
Dings will be asked, with purchase of the brakes, to provide in writing proof of similarity of the purchased brakes to the brakes tested in Limitorque test report 600198.
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