ML18054B437
| ML18054B437 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 02/16/1990 |
| From: | Berry K CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9002230142 | |
| Download: ML18054B437 (20) | |
Text
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consumers Power l'DWERINli MICHlliAN~S l'ROliRESS General Offices:
1945 West Parnall Road, Jackson, Ml 49201 * (517) 788-1636 February 16, 1990 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -
Kenneth W Berry Director Nuclear Licensing RESPONSE TO NRC'S QUESTIONS ON CPCO'S OPERABILITY DETERMINATION FOR VIKING INDUSTRIES POTTED CONNECTORS During the NRC EEQ follow-up Inspection 90005, the NRC indicated concern with the qualification of the potted Viking Industries connectors used in contain-ment for instrument and control circuits *. The NRC's concern relates to the lack of insulation resistance (IR) breakdown test data.
Consumers Power Company did have a specific test report on file for the connectors that supports their qualification.
However, the test report did not contain measurements of insulation breakdown values during the LOCA test process.
Consumers Power Company acknowledges that, the filed test report does not provide full qualification via the type testing method of the plant-specific application.
As this concern may also apply to other equipment qualifications, we have reviewed the qualification packages for other penetration connectors and have reconfirmed that appropriate IR test data was taken during qualification testing and evaluated in the qualification package to assure acceptable circuit operation.
The purpose of this letter is to provide further information concerning the Operability Determination of the potted Viking connectors as requested in our February 8, 1990 phone conversation with the NRC.
Our Operability Determinations augmented by the information present in this submittal provides interim iustification that the potted Viking connectors will perform their intended function during a LOCA.
The final resolution of this issue will be the replacement of all Viking Industry potted connectors.
Every effort will be made to complete all replacements during the 1990 spring maintenance outage.
I Those connectors that cannot be replaced in the maintenance outage will be replaced in the 1990 refueling outage.
A specific schedule for replacement of J,I the Viking Industry potted connectors will be submitted by March 1, 1990.
In addition, as discussed in our February 7, 1990 letter, we plan to replace selected fuses in the motor operated valve control circuits as soon as practical.
in order to enhance design margins.
OC0290-0012-NL02 9002230142 900216 PDR ADOCK n~nnn?~~
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Nuclear Regulatory Commission Palisades Nuclear Plant Operability Determination for Potted Conn.
February 16, 1990 The NRC concern was initially identified in NRC Inspection Report 86032.
In response to the initial concern, Consumers Power Company elected to show that the potted Viking Industries connectors were manufactured and tested to military specifications (MIL SPEC No 3106), and use the MIL SPEC data on IR breakdown to establish qualification of the connectors.
This method was chosen because no LOCA test was available which monitored IR breakdown during the test.
CPCo believed that this approach met the applicable qualification requirements of the DOR Guidelines.
2 In the recent follow-up EEQ Inspection 90005, the NRC noted that we did not have actual test data for the potted Viking connectors IR breakdown.
- However, the NRC indicated use of the MIL SPEC may be acceptable if Consumers Power Company provided documentation the potted Viking connectors were procured and tested to meet the MIL SPEC.
Although information contained in our EEQ files and discussed with your inspectors during our recent EEQ inspection provides persuasive evidence the connectors met the MIL SPEC requirements, Consumers Power Company was unable to provide documentation that the potted Viking con-nectors were procured and tested to the MIL SPEC.
Consumers Power Company still believes the use of the MIL SPEC does provide a reasonable, conservative approximation of IR breakdown for the connectors during a LOCA.
This belief is based on the comparison of the MIL SPEC based calculated values to actual test data collected for other connectors (Celmark and Amphenol).
Without documentation of actual MIL SPEC testing, the NRC determined that the qualification of the potted Viking connectors was in question and requested that an operability determination be prepared.
The operability determination was presented in two parts, instrument circuits and control circuits.
Since Consumers Power Company did have test data showing that the IR values are acceptable before and after the LOCA, and that the connector would not cata-strophically fail, the operability determinations as presented in our letters dated February 6 and 7, 1990 focused on the changes in IR and its impact on circuit operation during the transient.
The NRC indicated that the opera-bility determinations were acceptable with exceptions.
The exceptions were in the form of six questions.
Consumers Power Company's detailed response to these questions is attached.
In our response we used a test report for an Amphenol connector and performed a comparative analysis to the Viking potted connector.
This comparative analysis is used to provide a value for IR breakdown during the LOCA event.
The IR current loss developed in this analysis shows that our assumption of 1 Amp in the operability determination for control circuits is conservative. It also shows the IR breakdown value based on the MIL SPEC used in our instrumentation circuit operability determination was conservative.
OC0290-0012-NL02
Nuclear Regulatory Commission Palisades Nuclear Plant Operability Determination for Potted Conn.
February 16, 1990 3
Based on the information presented in this letter and our letters of February 6, 1990 and February 7, 1990 Consumers Power Company believes that although we have not been able to provide specific test data or document strict adherence to the MIL SPEC, the information presented shows that the connectors have a very high probability of performing their intended function during a LOCA.
Kenneth W Berry Director, Nuclear Licensing CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachment OC0290-0012-NL02
OC0290-0012-NL02 ATTACHMENT Consumers Power Company Palisades Plant Docket 50-255 RESPONSE TO NRC'S QUESTIONS ON CPCO'S OPERABILITY DETERMINATION FOR VIKING INDUSTRIES POTTED CONNECTORS February 16, 1990 14 Pages
J*
RESPONSE TO NRC'S QUESTIONS ON CPCO'S OPERABILITY DETERMINATION FOR VIKING INDUSTRIES POTTED CONNECTORS General Discussion In January 1990, the NRC conducted a follow-up EEO.audit at the Palisades Nuclear Plant.
As a result of the audit, a concern was raised by the NRC regarding the qualification of Viking Potted Connectors (3).
Consumers Power Company submitted two Operability Determinations (OD's) (1, 2) one on instru-ment circuits and one on control circuits.
Based upon the staff's review of these OD's additional information was requested during a February 8, 1990 phone conversation. ' During this discussion, six questions were asked by the NRC.
These six questions are documented below!
With Respect to Instrument Circuits o In the assumption section there is a discussion of a typical error for connectors being +/- 2% of the total loop error.
Provide a basis for this value and how it affects the entire instrument loop.
o Regarding M0-3016, interlock credit is taken for the placement of a jumper.
Provide information on the environment to which an individual would be exposed to place this jumper.
o Regarding input to Low Temperature Overpressure Protection (LTOP), a basis needs to be provided for our statement that the IR losses will recover to an acceptable level before the instrument is required to operate.
Also provide any available information on the environmental conditions when operation is needed.
o With respect to PT-0102B/D, provide information on what the environment would be.
Also determine if a break could be near the penetration area.
With Respect to Control Circuits a In discussions on solenoid valves (SV) it is assumed that they (SV's) will deenergize or their fuse will blow.
If the fuse doesn't blow, it must be shown that there is not enough leakage current to keep the SV energized or to reenergize it.
In this discussion, the assumption that leakage current will not exceed 1 Amp is based on a typical fuse size used in qualification testing.
This assumption is not considered acceptable.
o In motor operated valve circuitry a fuse is expected to carry circuit current at least until the valve has completed its actuated stroke, CPCo must address the margins in the calculated fuse characteristics.
MI0290-1725A-TC01
- ).
Four of the information requests resulted from the lack of insulation resistance (IR) test data to substantiate the conclusions reported in the OD.
Therefore the methodology for this analysis consists of establishing a basis for Viking connector IR data and assessing the impact this IR data has on the safety-related circuits of which the connectors are a part.
The steps are as follows:
o The original analysis provided in the OD's (1,2) assumed a 1.0 Amp leakage current.
This was based upon the high probability that a 1.0 Amp fuse was used in the LOCA test circuit for the Viking connectors (11).
A 1.0 Amp leakage current would represent a significant breakdown in connector insula-tion for a control circuit application and is considered excessive for an instrumentation circuit (ie, 4-20 mA).
o An IEEE 323-1974 type test report (10) has been obtained for an Amphenol triax connector assembly (Amphenol Plug No 53175-1004 and Amphenol Receptacle No 52975-1001).
Since this test included logging of IR data throughout the LOCA test, the first step of this methodology entails establishing an IR value for the Viking connectors by performing a comparative analysis of the Viking connectors and the tested connectors.
o After the basis for utilizing the IR test values from the Amphenol test report (10) has been established, a corresponding maximum leakage current can be calculated for both instrument and control circuit applications.
o Using the new IR leakage current, permits NRC concerns to be addressed.
Comparative Analysis In order to utilize IR results from the Amphenol triax connector test report (10), it must be proven that the installed connectors are equivalent or superior in design and configuration to those tested for in-containment service conditions, and that the test conditions under which the Amphenol connector was tested envelop the conditions postulated for the Viking connectors.
The critical characteristic that quantifies connector electrical performance is its insulation resistance (IR),
Variations in IR during a LOCA condition are primarily due to the presence of moisture inside the connector at critical locations and excursions in ambient temperature.
Excessive moisture intrusion along with elevated ambient temperatures could lead to eventual IR breakdown and subsequent increase in leakage current to unacceptable levels.
The follow-ing serves to support the conclusion that use of the results of the triax connector test is a conservative qualification.
The connectors installed at Palisades feature more effective moisture barriers and therefore should experience less of a drop in IR, the IR drop for plant connectors, in effect, being only a function o~ temperature.
Three distinct pathways exist for moisture to penetrate a connector assembly and potentially lead to degraded IR.
These pathways are:
MI0290-1725A-TC01 2
- 1.
Penetration/Connector Receptacle Interface
- 2.
Connector Receptacle/Connector Plug Interface
- 3.
Connector Plug/Field Cable Interface Therefore, the approach taken in this analysis is to establish that the installed connectors provide an equal or better moisture intrusion barrier at each of these three interfaces than that of the tested connector.
Once this is established, then IR data obtained for the tested connector may be used to conservatively represent the IR of the installed connectors.
Connector Design The installed connectors under examination are Viking potted connectors for which the connector shells (plug and receptacle) were manufactured by two subsuppliers:
Amphenol/Bendix and ITT Cannon.
The connector internals were manufactured by Viking (2).
Amphenol/Bendix Specific part numbers for Amphenol/Bendix parts used by Viking Industries could not be identified.
However discussions with personnel at Amphenol/Bendix provides assurances that the parts would have been of high quality.
A potting compound (3) which is applied to the connector in the field, completely encap-sulates the interface between the cable and the connector's plug shell.
This application of potting compound constitutes the moisture intrusion boundary between the plug/cable interface.
In addition, all connectors inside contain-ment use a silicone rubber sealing washer or 0-ring at the receptacle/plug interface.
ITT Cannon The installed ITT Cannon Connector No CA-3106R36-4S conforms to MIL Spec MS-3106 (2, 8).
The "R" designator of the model number indicates that this connector is designed for high humidity service and has an intrinsic resistance to moisture intrusion due to 100% RH/spray.
This connector is also potted at its interface with the field cable in the same manner as the Amphenol/Bendix connectors.
It also uses a silicone rubber sealing washer or 0-ring at the receptacle/plug interface.
The result again is a connector assembly which is shielded from the influences of high humidity and spray.
Tested Connector Assembly The tested connector (10) consists of an Amphenol Plug No 53175-1004 and Amphenol Receptacle No 52975-1001.
The connector assembly is designed for a triax cable.
It is a commercial grade item with the exception that a radiation-resistant insulator (cross-linked polyethylene) was used in place of the commercical grade insulator (Rexolite) (7).
No MIL Spec information was identified for the tested ~onnector.
MI0290-1725A-TC01 3
The tested connector's assembly instructions (9) contain detailed requirements to ensure correct assembly of the connector, which is essential for proper functional perforniance of the connector in instrumentation applications.
The finished assembly consists of a large number of internal parts with very tight*
assembly tolerances which are depended upon to prevent moisture intrusion under
- LOCA conditions (7).
Unlike the Viking connectors, no addition of sealants are applied externally to prevent moisture intrusion at the cable/connector body interface.
Similar to the installed connectors, the tested connector's plug/receptacle interface is sealed with a silicon rubber gasket.
Configuration Viking Connectors The Viking connectors installed inside containment at Palisades have the Bendix potting compound surrounding the interface between the connector shells and the associated field cable.
The potting compound also partially covers the external shell of the connector.
The receptacle portion of the connectors are fitted into the steel bulkhead connector bodies which are brazed to the penetration recess plate on the end of the penetration canister.
The bulkhead connector pin support consists of a glass insulating material.
The resultant configura-tion consists of one part of the receptacle assembly recessed into a steel shroud (bulkhead body) and the plug assembly sealed to the field cable with the potting compound (3).
Tested Connectors The tested triax connector jack ~as mated to a stainless steel mineral-filled triax cable so that this cable could be swagelok fitted to the test chamber header plate to achieve a pressure seal.
The plug wa*s 'connected to a standard triax cable (Raychem 10504).
This results in all three interfaces of the tested connector being exposed to the LOCA test condition:
steel triax-jack, jack-plug, and plug-triax.
See Figure 1 of this analysis for an outline of the test configuration.
No provisions were made in the connector test configura-tion to shield it from the direct exposure to the combined influences of high temperature, pressure, 100% RH and chemical spray during the LOCA test.
The LOCA test environment was in direct contact with the exterior surface of the connector.
Therefore, the potential for moisture intrusion and subsequent test failure by excessively low IR readings was at a maximum.
Comparison and Evaluation of Moisture Barriers Penetration/Connector Receptacle Interface The moisture barrier at the penetration/receptacle interface of the installed connectors is provided by the brazed joint between the connector body and the recessed header plate of the penetration.
This method of sealing is considered to provide an absolute barrier against moisture intrusion. It is considered superior to the swagelok seal provided at the corresponding interface of the tested connector.
MI0290-1725A-TC01 4
Connector Receptacle/Connector Plug Interface The moisture barrier at the connector receptacle/connector plug interface is provfded by a silicone rubber gasket or 0-ring in both the installed and tested designs.
This design relies on forming a moisture seal by compressing the seal material against a mating surface.
The method of sealing and the materials employed to seal this interface in the installed and tested configurations are judged to be essentially equal and capable of providing an equally effective moisture boundary.
Connector Plug/Field Cable Interface The moisture barrier at the connector plug/field cable interface of the installed connectors is provided by a Bendix potting compound.
The tested connector relies on a mechanical compression fit between the cable and the connector plug body.
The method of sealing the installed connectors is considered superior to the tested connector.
IR Test Results The tested connector was LOCA-tested with all three moisture intrusion paths fully exposed to the test environment (10).
Hence moisture intrusion could have taken place through any one or all three of these paths.
However, in spite the test sequence severity, no significant moisture intrusion was evi-dent, as indicated by the excellent IR test results achieved.
The lowest (ie, worst) recorded IR value was 5.60E08 ohms (10).
Palisades Required Test Parameter (LOCA Environment)
The installed Viking Industries connectors are original equipment and therefore are qualifiable per 10CFR50.49K (DOR Guideline criteria).
They are not required to be type tested per IEEE 323-1974 for thermal aging, radiation aging, etc.
The only stipulation per DOR Guidelines is that type testing is preferred for accident conditions.
Section 4.2 of DOR Guidelines provides the basis for these connectors to be qualified only for LOCA condition (not MSLB) at Palisades, by taking credit for the redundant spray system.
The tested connector successfully passed a full type test per IEEE 323-1974 which consisted of the following type test sequence:
- 1.
Thermal aging@ 134 degrees C for 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> (40 year life@ 136 degrees F)
- 2.
Radiation aging to a total integrated dose of 2.2E08 rads from a Cobalt 60 source @ 0.62 Mrads/hour
- 3.
LOCA Test:
340 degrees F/105 ps1g for 15 minutes 300 degrees F/53 psig for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> 250 degrees F/15 psig for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Chemical spray = borated water @ 4000 ppm + NaOH buffered to 9.0 -
10.5 pH range.
Spray rate = 1.35 gpm for 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />, 15 minutes MI0290-1725A-TC01 5
IR data was recorded throughout the entire LOCA test sequence.
In order to utilize the IR data for Palisades specific application evaluation, the LOCA test parameters will be proven to envelop the plant requirements for LOCA.
- a.
Pressure:
The peak pressure required for Palisades is 69.23 psia (54.53 psig)
(6).
The peak LOCA test pressure attained was 115 psig which envelops the requirement.
- b.
Temperature:
The peak LOCA temperature is 282 degrees F (6).
See Figure 2 of this analysis for a comparison of the required versus tested LOCA temperature-time profile.
The peak LOCA test temperature exceeds the requirement by almost 60 degrees F.
The mismatch in initial rise time to peak temperature between the accident profile and test profile is due to test facility limitations and is not considered to compromise the applicability of the test.
- c.
Spray:
The spray requirement is chemical spray (1750 -
2000 ppm boron + 50 -
100 ppm hydrazine) for the initial 11 days into the accident (6).
The test meets the requirement for chemistry and was of sufficient duration to exhibit any influence which might degrade IR test data results.
- d.
Post-LOCA Duration:
The test is not evaluated for this criteria since this test is not utilized for aualification but rather only to demonstrate that its severity envelops the requirement, thereby establishing further justi-fication for using the IR data to support the OD's Comparative Analysis Conclusion It has been shown that the severity of the Amphenol test (10) greatly exceeds the requirement for LOCA testing at Palisades and demonstrates that a fullv aged connector still retains very favorable IR data (10).
The tested triax connector was LOCA-tested without anv external sealing materials applied whereas the installed Viking connectors are sealed at the penetration end/
receptacle body interface by brazing, at the plug/receptacle interface by an 0-ring, and at the cable/connector plug body interface by potting compound.
The sealing provided for the Viking connectors (brazing, 0-ring and potting com-pound) are concluded to be equal or better than the sealing (swage, gasket, mechanical fit) provided by the tested component.
Due to the conservative configuration of the tested connector in the LOCA test chamber compared to the sealed connectors in the plant, the test connector's construction compared to the installed connector constructions, and se~erity of MI0290-1725A-TC01 6
the LOCA test parameters compared to the Palisades LOCA environment a reasonable basis is provided for utilizing the IR data in the subject test report (10) to refine and support the operability determinations and instrument accuracy engi-neering analyses (which were located in EEQ files prior to Inspection 9005) where MIL SPEC IR values were used to assess instrument performance (18).
Leakage Current The lowest IR recorded in the test report (10) was 5.6E08 ohms.which occurred after reducing the LOCA test temperature from 340 degrees F to 300 degrees F (10).
Note that the IR data was measured with an applied voltage of 1500 VDC.
The resulting leakage current applicable to the affected AC/DC lE circuits at Palisades would be determined as follows:
AC Applications I (leakage) = V/R = 120VAC/5.6E08 ohms = 2.143E-07A For conservatism, 1.0 milliamp of leakage current is assumed for refining the OD's (1, 2) in the four areas of concern as they apply to AC applications.
This conservatively compensates for the possibility of capactive leakage effects.
DC Applications Leakage current for DC circuit applications was calculated in Reference 18 utilizing a minimum IR value from MIL SPEC MIL-C-5015G (18).
The MIL SPEC value gorresponding to our highest expected LOCA temperature (281°F) was 3 x 10 ohms.
At this IR, and a loop voltage of 30VDC, the resulting leakage current was determined to be 0.1 mA.
The percent error (%of loop signal indication) was determined to be 0.83%.
If the Amphenol triax connector test minimum IR was substituted into this analysis, the resultant leakage current would be significantly less than a pico amp with a resulting error of approxi-mately one tenth of a percent (indicated value).
Thus, the worst-case leakage current would have no noticeable effect on the operators' loop indication.
NRC CONCERNS The statement was made that the error associated with connectors in general, in which test data is available is typically less than+/- 2%" (2).
This statement was a conservative resolution of past analyses which quantified the percent (of indicated value) error of other instrument loop components.
A specific review of Reference 18 reveals that all components (with the exception of transmitters) have errors less than +/- 2%.
Our calculations show the largest contributor being chemically linked cable resulting in a 1.09%
error and the potted connector at 0.83% error.
MI0290-1725A-TC01 7
Therefore it is concluded that the actual percent error contribution for the connectors is well below the previously assumed +/- 2% figure.
Pressurizer Pressure/Safety Injection Transmitters (PT-0102B and PT-01020)
Based on comparisons between the installed Viking and the tested Amphenol connectors, it has been shown that the IR of the Viking connectors will not degrade by any significant amount.
The conservative value of leakage current calculated will not degrade the safety function of these transmitters during any part of the postulated LOCA.
We also reviewed the appropriate drawings to determine if a small break LOCA could occur near the north penetration area, since this is where the penetra-tions for PT-0102B and PT-01020 are located.
There are some PASM panel sample lines (approximately 1/2 110) in the north penetration area, approximately 15 feet from the connectors.
The orientation of the lines is such that a break would result in spray either straight up or away from the penetration area.
Therefore a small break LOCA will not result in abnormal localized environmental effects on the connectors.
The Accident and Transient Analysis Section reviewed the containment response to the spectrum of small break LOCA events analyzed in Chapter 14 of the Palisades FSAR (17).
The containment response is summarized below:
0.1 ft2 Cold Leg Break Reactor Trip Time (TM/LP)
SIAS Containment Temperature @ 27.0 seconds Maximum Containment Temperature Final Temperature (end of analysis) 0.02 ft2 Cold Leg Break Reactor Trip Time (TM/LP)
SIAS Containment Temperature @ 108.0 seconds Maximum Containment Temperature Final Temperature (end of analysis) 0.0005 ft2 Cold Leg Break Reactor Trip Time (TM/LP)
SIAS Containment Temperature @ 3650 seconds Maximum Containment Temperature Final Temperature (end of analysis)
MI0290-l 7 25A-TC01 14.0 27.0
~ 175 244 F 202 F 88.0 108.0
~ 168 208 F 184 F 3650 3650
~ 153 157 F 119 F 8
seconds seconds F
@ 782 seconds
@ 9000 seconds seconds seconds F
@ 1490 seconds
@ 9000 seconds seconds seconds F
@ 3680 seconds
@ 9000 seconds
Based on the low value of leakage current (approximately 1 pico Amp) predicted at peak LOCA temperatures (281°F), the expected leakage current and coresponding loop error contribution at the ESF actuation times above would be acceptable.
Solenoid Valve, Failure Analysis This analysis responds to the concern raised regarding the potential for IR leakage currents to be of a sufficient magnitude to cause solenoid-operated valves (SOVs), which are required to deenergize to perform their safety func-tion, to be reenergized via the IR leakage path.
LOCA-induced IR connector leakage was established based on a comparison of the installed connectors to a tested configuration.
A conservative estimate of 1.0 mA was established as a conservative bounding value for IR leakage current in a 120 VAC circuit.
A calculation was performed which shows that the subject solenoid valves require a 140 mA current to reenergize.
Therefore, it is concluded that these solenoid valves will not reenergize as a result of connector IR leakage.
M0-3008, M0-3010, M0-3012, M0-3014 Low Pressure Safety Injection Motor Operated Valves These motor operated valves provide the path for low pressure safety injection to the reactor.
These valves receive an immediate open signal on SIS.
The LOCA analysis acceptance criteria is 14 seconds for valve stroke time (1).
The LOCA analysis also includes 14 seconds of delay for DG start and other delays and conservatism.
Therefore the LOCA a~f9ysis assumes delivery time for low pressure injection flow within 28 seconds.
As shown on E-48 Sheet 3 (6), temperature rise for LOCA would be at the peak in approximately 6 seconds.
The IR losses due to temperature increase would occur some time after 6 seconds.
The previous submittal conservatively assumed gross IR losses of 1 Amp at 7 seconds which could cause the control fuse in the MOV control circuit to open after it has completed its function of opening the valve.
Further refinement of the original analysis has been performed to demonstrate the level of conser-vatism.
Investigation has shown that the IR losses in the Viking Connector originally assumed to be 1 Amp would actually be less than 1 milliamp.
The conclusion is that the MOV's will be able to perform their function without tripping the control circuit fuse.
Detailed Analysis for M0-3008 and M0-3010 During an accident, the valve is required to open.
While the valve is opening, the normal current draw of the control circuit includes the motor starter contactor relay, one auxiliary relay and four indicating lamps.
After the valve completes its stroke, the normal current draw includes only two indicat-ing lamps (12, 13, 14).
MI0290-1725A-TC01 9
Normal operating current while valve lS opening (1):
M/S Cutler Hannner ASODNVO Size 2 Catalog Data 23 VA Aux Relay GE 12HFA51A49H 32 VA Four Ind. Lamps @ 6W Each 24 VA 79 VA 79 VA I 120V AC = 0.658 Amps Normal operating current after valve is opened:
Two Ind. Lamps @ 6W Each 12 VA 12 VA I 120V AC = 0.100 Amps Since these electrical devices are constant impedance, the worst case current draw was determined at rated voltage.
The inrush current of the motor starter contactor relay and the auxiliary relay were neglected since they are of such short duration that the I 2 z resultant heating effect on the fuse is negligible compared to the continuous current component of heating.
Using the l milliamp leakage current during the LOCA event, the total control circuit current would be less than 0.66 Amps while the valve is opening during the accident and less than 0.11 Amps after the valve is opened.
Per walkdowns, the control circuit is protected by a 0.6 and 2 Amp fuse in series.
It was found after a review of the 0.6 Amp fuse m1n1mum melting time current curve (16) that the fuse wou.ld not trip at 0. 66 Amps for at least 300 seconds.
Since the control circuit current is less than 0.66 Amps for a duration of 14 seconds during the valve stroke time and reduces to less than 0.11 Amps after the valve is opened, the fuse will not trip as a result of opening the valve during a LOCA event.
Thus the margin of safety in this case is 286 seconds, (300-14).
Detailed Analysis for M0-3012 During an accident, the valve is required to open.
While the valve is opening, the normal current draw of the control circuit includes the motor starter contactor relay, one auxiliary relay and four indicting lamps.
After the valve completes it stroke, the normal current draw includes only two indicating lamps (12, 13, 14).
MI0290-1725A-TC01 10
Normal operating current while valve lS opening:
M/S Cutler Hanuner ASODNVO Size 2 Catalog Data 23 VA Aux Relay GE 12HFA51A49H 32 VA Four Ind. Lamps @ 6W Each 24 VA 79 VA 79 VA I 120V AC = 0.658 Amps Normal operating current after valve is opened:
Two Ind. Lamps @ 6W Each 12 VA 12 VA I 120V AC = 0.100 Amps Since these electrical devices are constant impedance, the worst case current draw was determined at rated voltage.
The inrush current of the motor starter contactor relay and the auxiliary relay were neglected since they are of such short duration that the heating I 2z effect on the fuse is negligible compared to the continuous current component of heating.
Using the 1 milliamp leakage current during the LOCA event, the total control circuit current would be less than 0.66 Amps while the valve is opening during the accident and less than 0.11 Amps after the valve is opened.
Per walkdowns, the control circuit is protected by a 1 and 2 Amp fuse 1n series.
It was found after a review of the 1 Amp fuse m1n1murn melting time current curve (16) that the fuse could operate continuously at 0.66 Amps of current without tripping.
Therefore the control circuit will not trip as a result of opening the valve during a LOCA event.
Detailed Analysis for M0-3014 During an accident, the valve is required to stroke open.
While the valve is opening, the normal current draw of the control circuit includes the motor starter contactor relay, one auxiliary relay and four indicting lamps.
After the valve completes it stroke, the normal current draw includes only two indicating lamps (12, 13, 14).
MI0290-1725A-TC01 11
Normal operating current while valve is opening:
M/S Cutler Hammer M/N 9656Hl58A, Size 1 Catalog Data Aux Relay GE 12HFA51A49H Four Ind. Lamps @ 6W Each 20 VA 32 VA 24 VA 76 VA 76 VA / 120V AC = 0.633 Amps Normal operating current after valve is opened:
Two Ind. Lamps @ 6W Each 12 VA 12 VA/ 120V AC= 0.100 Amps Since these electrical devices are constant impedance, the worst case current draw was determined at rated voltage.
The inrush current of the motor starter contactor relay and the a~xiliary relay were neglected since they are of such short duration that the I t component which would heat the fuse is negligible compared to the continuous current component of heating.
Conservatively, using the 1 milliamp leakage current during the LOCA event, the.
total control circuit current would be less than 0.64 Amps while the valve is opening during the accident and less than 0.11 Amps after the valve is opened.
Per walkdowns, the control circuit is protected by a 1 and 2 Amp fuse in series.
It was found after a review of the 1 Amp fuse minimum melting time current curve (16) that the fuse could operate continuously with 0.64 Amps of current without tripping.
Therefore the control circuit will not trip as a result of opening the valve during a LOCA event.
Interlock for M0-3016 Input to LTOP (PT-0104B)
If M0-3016 would not perform its function a jumper would be installed.
This is accomplished by placing the jumper across the output contacts of a current switch (PS-0104B) which is located in the control room, panel C-12.
Therefore the individual performing the work would not be exposed to a harsh environment.
With respect to IR recovery, a concern no longer exists since the comparison between the installed Viking and tested Amphenol connectors has shown that the IR of the Viking connectors will not degrade by any significant amount.
The conservative value of leakage current calculated will not degrade the safety function of this transmitter during any part of the postulated LOCA.
MI0290-1725A-TC01 12
Conclusion This comparative analysis provides the basis for utilizing the Amphenol triax cable connector test data to establish IR leakage values applicable to the Viking connectors installed at Palisades.
Subsequently, these values are to be used as additional information for justifying continued operation of the Palisades Nuclear Plant in response to the four NRC concerns.
References
- 1.
CPCo Safety Review No PS&L 90-0181 (Cale No MI0290-1722A-TC01), Dated 2/7/90; "Operability of Control Circuits With Viking Potted Connectors."
- 2.
CPCo Safety Review No PS&L 90-0167 (Cale No MI0290-008A-TC07), Dated 2/6/90; "Operability of Instrumentation Circuits With Potted Connectors Inside Containment."
- 3.
EEQ File E-48, Sheet E2-2, Rev 9 - 9/12/89; "Viking Electrical Containment Penetrations and Bendix Connectors."
- 4.
EEQ File E-48, Sheet MISC-4, Rev 7 - 2/1/90; "Celmark Electrical Penetra-tion Connector."
- 5.
EEO File E-48, Sheet 6CI; AETL Test Report No 5Lf8-8296, Dated 8/6/80; "Thermal Aging, Radiation Exposure, Seismic Qualification and Loss of Coolant Accident (DBA) Test on Electrical Connector Assemblies - Various Part Numbers."
- 6.
EEQ File E-48, Sheet 3A, Rev 8; "EEQ Environments and Profiles."
- 7.
ROC Between BM Lory (Impell) and D Ferris (Amphenol) - 2/9/90.
- 8.
ROC Between B M Lory (Impell) and A Shaw (ITT Cannon) - 2/9/90.
- 9.
Telecopy of Amphenol Connector Assembly 52975-1001/53175-1004, Dated 2/9/90.
- 10.
Westinghouse Report No PEN-TR-87-49, Dated 11/22/82; "Qualification Report on Triax Connector for Use in Beaver Valley StAtion - Unit No 2 Following the Guidelines of IEEE 323-1974 and 317-1976."
- 11.
Wyle Lab Test Report No 43913-2, Dated 2/25/78; "Accident Test on Four Electrical Connectors for Consumers Power Company - Jackson, MI" (E-48 Sheet 6-BG).
- 12.
CPCo Drawing No E-244, Sheet 1, Rev 16.
- 13.
CPCo Drawing No E-244, Sheet 13, Rev 4.
- 14.
CPCo Drawing No E-244, Sheet 3, Rev 1.
- 15.
ROC Between B M Lory (Impell) and M Ferens (CPCo) - 2/9/90.
MI0290-1725A-TC01 13
- 16.
Telecopy of Bussman Avg Melt Time Current Curve for Bussman FRN-R Fusetron Duel Element Fuses.
- 17.
CPCo Letter RJG 90-006, Small Break LOCA Containment Response, Gerling to Toner 3/12/90.
- 18.
CPCo Engineering Analysis EA-BDM-87-04 (E-48 Sh 6 DR) "EEQ Evaluation of Insulation Resistance."
- 19.
Technical Specification Surveillance Procedure Q0-5 "Valve Testing Program" basis document.
MI0290-1725A-TC01 14
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