ML19277G242
| ML19277G242 | |
| Person / Time | |
|---|---|
| Issue date: | 02/06/1984 |
| From: | Vaughn Thomas NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Baer R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML19277G243 | List: |
| References | |
| FOIA-84-441 NUDOCS 8402210483 | |
| Download: ML19277G242 (9) | |
Text
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FEB C 19M MEMORANDUM FOR:
Robert L. Baer, Chief Engineering and Generic Communications Branch Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement THRU:
Alexarider W. Dromerick, Chief, Section A Engineering and Generic Communications Branch Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement FROM:
Vincent D. Thomas, Sr. Instrumentation & Controls Engineer Engineering and Generic Communications Branch Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement
SUBJECT:
COMMENTS ON FRC MEETING REPORT ON ROCKBESTOS CABLE ISSUE IN IE OFFICES - DATED JANUARY 5, 1984 Cognizant people from RIV, NRR, Franklin Research Center (FRC), and IE met on Thursday, January 5,1984 in the East West Towers West Building in Bethesda, Maryland to discuss outstanding issues related to the Rockbestos Cable Company production program.
The enclosed report from FRC is a compilation of the minutes of the January 5, 1984 meeting.
IE has reviewed the roort and believes it accurately describes the results of discussions on all items of concern addressed during the meeting.
With respect to the recommendations (items of concern) provided on page 5 of the FRC report, our views on each item of concern follow.
Item of Concern No. 1 - Retesting:
Rockbestos has agreed to revise its current retesting and sampling methodology to verify that cable qualified more closely reflects the requirements specified in the latest applicable ICEA (formerly IPCEA) standard.
Rockbestos has also agreed to submit its mcdified retest program to the Region IV Vendor Inspection Branch for review and comment. Uldis Potapovs of Region IV has agreed to followup on this item to assure that Rockbestos fulfills their commitment.
Robert L. Baer FEB 6 1984 Item of Concern No. 2 - Conductor Insulation Nonconformances:
Followup action by IE of the two cable reels in question, identified as G-34789 and G-32923 and shipped to Beaver Valley Unit 2 and Nine Mile Point Unit 2, respectively, revealed that five (5) additional cables reels were produced from the sane production run as cable reel G-34789 and were also shipped to Beaver Valley Unit 2.
We found that eight (8) additional cable reels were produced from the same production run as cable reel G-32923 and shipped to Nine Mile Point Unit 2.
According to Stone & Webster, approximately 13,000 feet of cable comprise the six reels at Beaver Valley Unit 2, and approximately 19,000 feet of cable are involved in the nine reels of cable at Nine Ilile Point Unit 2.
With respect to findirgs resulting from followup action on the reels in question at Beaver Valley Unit 2, only ten (10) cable cuts out of 986 cable cuts from the (six) reels in question, are being used in safety-related electrical circuits. However, all of the 10 cable cuts are used in areas considered as mild environnent. According to both Duquesne Light Company and Stone & Webster, cable reel G-34789 does in fact meet all requirements as specified in applicable ICEA Standa rd S-66-524. Additionally, the licensee stated that since this ICEA standard is the document applied to determine adequacy of this specific cable reel, Beaver Valley in turn, accepted the cable despite the minor deviation from the Rockbestos standard value which is more stringent than the ICEA standard.
To close cut this specific item of concern, Region IV is preparing a formal request to Stone & Webster to confirm this acceptance action to Rockbestos.
Accordingly, we believe that upon receipt of this confirmation from Stone &
Webster, the issue in question concerning the six cable reels at the Beaver Valley Unit 2 can be resolved.
With respect to cable reel G-32923 and the eight sister reels shipped to Nine Mile Point Unit 2, Stone & Webster and the licensee stated (as in the case at Beaver Valley) that the parameter values for cable production as specified in the applicable ICEA S-66-524 Standard were the governing values for accepting cables and not those values specified by the manufacturer (Rockbestos). As a consequence, all electrical and physical parameter values obtained in each of the three retests of samples from cable reel G-32923 do in fact meet all applicable ICEA requirements.
On this basis, Stone & Webster and the licensee have accepted cable reel G-32923 and the eight related cable reels as suitable for safety-related applications at Nine Mile Point Unit 2 station.
As in the case at Beaver Valley, Region IV will also request a formal response from Stone
& Webster to confirm this position.
Additionally, subsequent to receiving the above letters of acceptance from Stone & Webster, FRC will include these findings in an addendum to subject report identified as FRC-FC 5569-306.
Briefly, Report FC 5569-306 provides results of the FRC review of documentation and retest data referenced by the Rockbestos Company in response to the NRC investigation that began in May 1982.
FEB 6 1984 Robert L. Baer
-3_
Item of Concern No. 3 - Insulation Resistance Test Voltages:
We concur in the FRC recommendation, " acceptable," in that Rockbestos indicated that low voltage insulation test equipment is being used only on certain coaxial types of cables produced.
We believe that this item of concern can now be closed.
Item of Concern No. 4:
Rejacketed Cable: On the basis of the judgment provided by the NRC/FRC cable consultant, E. Eich, that says: apparent deviations f rom specification values, would not "substantially change the ability to perform the intended function, that is, if cables with conforming jackets are suitable for the service; cables with these jackets are substantially equally suitable," we agree that rejacketing of cable, as discussed, is acceptable for the service intended.
Environmental Qualification:
Finally, with regard to environmental quali-fication of reworked or rejackced cable, we agree with the FRC suggestion that a feasibility study be implemented by the NRC to detennine if these types of cable need to be individually requalified.
We reconmend that NRR/EQB pursue the feasibility study effort of environmentally qualifying rejacketed cable.
Vincent D. Thomas Sr. Instrumentation & Controls Engineer Engineering and Generic Communications Branch Division of Emergency Preparedness and Engineering Response, IE cc:
A. W. Dromerick, IE DISTRIBUTION ~
U. Potapovs, RIV ctCS I. Barnes, RIY DEPER R/F T. Le, IE EGCB R/F A. Masciantonio, NRR VDThomas R/F V. S. Noonan, NRR ELJordan G. Toman JGPartlow Franklin Research Center SASchwartz 20th and Ben Franklin Parkway VDThomas Philadelphia, PA 19103
- SEE PREVIOUS CONCU NCES
- EGCB:DEPER:IE EPER:IE VDThomas Vg g erick 1/31/84:mkm
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Robert L. Baer Item of Concern No. 3 - Insulation Resistance Test Voltages:
We concur in the FRC recommendation, " acceptable," in that Rockbestos indicated that low voltage insulation test equipment is being used only on certain coaxial types of cables produced.
We believe that this item of concern can now be closed.
Item of Concern No. 4:
Rejacketed Cable:
On the basis of the judgment provided by the NRC/FRC cable consultant, E. Eich, that say.s:
apparent deviations from specification values, would not "substantially change the ability to perform the intended function, that is, if cables with conforming jackets are suitable for the service; cables with thesii jackets are substantially equally suitable," we agree that rejacketing of cable, as discussed, is acceptable for the service intended.
Environmental Qualification:
Finally, with regard to environmental quali-fication of reworked or rejacketed cable, we agree with the FRC suggestion that a feasibility study be implemented by the NRC to determine if these types of cable need to be individually requalified.
We recommend that NRR/EQB pursue the feasibility study effort of environmentally qualifying rejacketed cable.
Vincent D. Thomas Sr. Instrumentation & Controls Engineer Engineering and Generic Communications Branch Division of Emergency Preparedness and Engineering Response, IE cc:
A. W. Dromerick, IE DISTRIBUTION-U. Potapovs, RIV I)Ls I. Barnes, RIV DEPER R/F T. Le, IE EGCB R/F A. Masciantonio, NRR VDThomas R/F ELJordan C. Toman JGPartlow Franklin Research Center SASchwartz 20th and Ben Franklin Parkway VDThomas Philadelphia, PA 19103 EGCB:DEPER:IE Wy
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MEETING REPORT FRC Project 5569-306 Task 3006
Subject:
Rockbestos Cable Company Manufacturing Testing Location: Room 550, East West / West Towers Bldg.,
Bethesda, Md.
Date and Time:
January 5, 1984, 9 am Attendees:
Rockbestos Robert J. Gehm Eugene J. D' Aquanno George G. Littlehales NRC:
s Robert Baer A. W. Dromerick Vincent Thomas Uldis Potapovs Ian Barnes*
Thomas Le*
Armond Masciantonio*
FRC:
Gary Toman s' Edward Eich (Consultant)
- Part-time attendance Purpose of Meeting To discuss with Rockbestos personnel recommendations contained in FRC Report F-C5569-306, " Evaluation of Rockbestos Cable Manufacturing Testing" and open questions concerning information contained in the letter dated November 9, 1983 from George Littlehales of Rockbestos to Gary Toman of FRC (attached for reference).
Discussion Since the questions concerning the Rockbestos letter of November 9, 1983 overlapped the recommendations from FRC Report F-C5569-306, the meeting began with a discussion of the FRC/NRC concerns in regard to the letter. The letter was in response to questions contained in a letter from G. Toman to G.
Littlehales dated October 27, 1983 (also attached for reference). L&
_ _ Frankhn R, es,earch Center
FRC Request 1 from October 27, 1983 letter "For those reels of cables experiencing XLPE insulation test nonconformances (i.e., Stone and Webster Engineering Corp. [SWEC), Beaver Valley Unit 2, one reel; SWEC, Nine Mile Point Unit 2, two reels; and SWEC, Shoreham Nuclear Power Station, one reel), provide a description of the cables involved and a list by reel number and purchaser of all reels manufactured in the same manufacturing runs that were purchased for nuclear safety-related service."
The Rockbestos response to this request described the results of the retests on the subject cable and stated that the results met all requirements typically specified for nuclear safety-related cable and that Rockbestos did not believe that identification of nuclear cable employing single conductors from the same run was necessary.
/
Mr. Toman discussed his review of this response and his comparison of the results contained in the response with the data sheets for the Rockbestos retests which were obtained by FRC during a meeting at the Rockbestos plant on August 9 and 10, 1983.
Mr. Toman noted that for one of the cables (Beaver Valley Reel G34789), the stability factor exceeded the Rockbestos " guaranteed" value (0.6 vs. 0.5) and that for all but one of the other five reels described in the response, multiple retests were required to obtain passing values for EM-60 electrical water absorption or tensile strength or elongation tests. It was also noted that one reel (Nine Mile Point Unit 2 Reel E024B-774) had f ailed the UL vertical VW-1 (UL-83) flame test and then subsequently passed an ICEA S-19-81 flame test and was deemed acceptable.
Rockbestos responded that they believed that the problems with the initial retests were related to anomalies in the performance of the tests or preparation of the test sample rather than to a problem with the materials although, even at the time of testing, it would have been difficult to prove that either the test rig or the test sample was the cause. They also noted that at no time did a test result exceed an IPCEA S-66-524 limit.
With regard to the change in flame test procedure, Rockbestos stated that the more stringent UL vertical VW-1 (UL-83) flame test was inadvertently placed on the test form as a requirement and that this was not required for this type of cable by standard or purchase order and that the ICEA S-19-81 was the correct test to perform.
Mr. Eich stated that variations from the values normally recorded for the cables would be cause for concern. He believed that the Rockbestos
" guaranteed" values were more representative of the cable parameters than the less restrictive 1PCEA S-66-524 values. Rockbestos stated that the Rockbestos
" guaranteed" values were values that the cable would generally be able to meet and were based on Rockbestos' knowledge of the cable rather than on firm statistical data.
Mr. Eich reviewed the data for the cables of concern (one AM
_ _ Frenkhn, Research Center
, n r._
reel of cable, G33955, eas rejected by the customer and is no longer of concern). He determined that the problems with elongation and tensile strength were of little long-term concern.
However, Mr. Eich maintains that the test f ailures in the EM-60 tests are significant in that the EM-60 test does give some indication of the ability of the cable to function with time and that the deviating values appeared to be beyond the range that would be expected for this type of cable.
FRC Recuest 2 from October 27, 1983 "For those cables that did not pass EM-60 accelerated water absorption tests, provide an engineering justification that these cables are acceptable for nuclear safety-related service. This justification should include those cables that passed retests as well as those that did not."
The Rockbestos' respense to this request was that the test method was at f ault rather than the samples being tested and that the samples that failed the test w2re those that had been allowed to intermittently touch the side or top of the water bath chamber while readings were being taken.
Mr. Toman asked if Rockbestos referred to the submerged portion of the cable when indicating that the samples touched the tank.
Rockbestos stated yes.
Mr. Toman then asked why this should make a difference since the water in the test was meant to provide a conducting path between the conductor insulation and the tank.
Rockbestos stated that the water bath had resistance and dielectric strength and that results could change when the tank was touched by the cable.
Rockbestos cited a test in which some cables were allowed to touch the tank during some tests and others were not.
All the cables that did not touch the tank passed, whereas some, but not all, of the cables that touched the tank had scme problems in the EM-60 test results. The reason why some passed and others did not when touching the tank could not be determined.
Mr. Eich did not believe that the results of this test conclusively proved that improper test methodology was the cause of the EM-60 failure.
Rockbestos stated that since instituting procedures that assure that no cable touches the tank during testing, only two instances of an EM-60 failure have occurred, which is a major reduction in failure rates.
FRC Recuest 3 f rom October 27, 1983 lettet "For cables that are to be reworked or rejacketed (i.e., those for SWEC, Nine Mile Point Unit 2), provide a description of the testing performed prior to rejacketing that provides assurance that no damage has occurred to the conductors or conductor insulation during jacket removal and handling."
Rockbestos stated in their written response that no testing of the conductor insulation is performed prior to rejacketing. After rejacketing, dielectric strength, insulation resistance, and conductor resistance tests are performed. /=
.. FreN:n Research Center
.r.,
v Mr. Toman asked what proof was available that the conductor insulation was not damaged or significantly stressed during rejacketing such that original qualification data were not invalidated.
Rockbestos stated that the rejacketing of the cable was less stressful to the conductors in that fewer operations were performed on the conductor and that the twisting from the cabling procedure was not repeated and that they did not believe that a significant increase in stresses was added. With regard to testing, Rockbestos stated that no production test existed that would expose minor damage done to conductor insulation either in initial jacketing or rejacketing. Significant damage would be detected by the production tasts.
FRC Request 4 from October 27, 1983 letter "The description of the resolutica status for cable provided to SWEC, Nine Mile Point Unit 2 (ten reels total:
six reels, Hypalon jacket testing nonconformances; two r eels Hypalon testing and XPLE insulation testing nonconformanceL; and two reels, XLPE insulation testing nonconformances) is not clear.
Please provide a listing by reel of the cable description, the initial problem, and the resolution of the problem. Please provide this information for the six additional reels of cable identified as needing rework."
Rockbestos responded with the status (see full respcnse in Lttachment) of the cables.
Mr. Toman asked if Rockbestos had any updates on the status of the cables.
Mr. Littlehales responded that for the six additional reels of cable associated with reels rejected by the Stone and Webster Engineering Corporation for Nine Mile Point Unit 2, five had been rejacketed and were in the process of being retested and one (Reel G34350) had been rejected and was to be replaced with new cable.
Further Concerns from FRC Report F-C5569-306 1.
Retesting - Mr. Toman asked if a formal policy existed on retesting of cable when a test failurc was recognized.
Mr. Littlehales stated that generally two retests would be performed but that formal instructions for retesting and rejecting cable did not exist.
2.
Use of Low Voltage Insulation Resistance Measuring Devices -
Rockbestos stated that confusion existed with regard to use of low voltage insulation test equipment. This equipment was used only for a particular type of coaxial cable used with sensitive electronic equipment. For all other cable, high voltage insulation test equipment is used. The coaxial cable is tested at low voltage because previous use of high voltage equipment had lef t residual charges on the cable which had resulted in damage to the electronic devices when connected to the cable. &==
...,Frankhn,Research Center
4 4
Recommendations Resulting from the Meeting 1.
Retesting - FRC recommends that formal policy be adopted by Rockbestos for retesting and rejecticn of conductors and cable based on the IPCEA S-66-524 requirements for sampling, retesting, and rejection.
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2.
Conductor Insulation Nonconformances - With regard to those cables
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having slight deficiencies during retesting in tensile strength and elongation, there is little concern for long-term operability because the tensile strength and elongation required of the insulation can never approach the as-tested levels without first breaking the conductors.
With regard to the two cables with conductor insulation that did not pass EM-60 accelerated water absorption tests, concern remains that the insulation could deteriorate with time. The EM-60 test gives an indication of the ability of the insulation to withstand moisture by-testing insulation properties when submergei for two weeks.
Therefore, Reels G-34789 (Beaver Valley) and G-32923 (Nine Mile Point
- 2) and cable produced in the same manufacturing runs should either be subjected to a program of in-situ testing or replaced unless the cable is not used in safety-related circuits or it is not subjected to harsh environments while in service.
3.
Insulation Resistance Test Voltages - Rockbestos' response that low voltage insulation test equipment is used only on certain coaxial cables is acceptable.
4.
Rejacketed Cable and Environmental Qualification - As a result of the meeting, it was determined that environmental qualification tests on the rejacketed cables would not conclusively prove that occasional damage had occurred to the conductor insulation during rejacketing because results would be highly dependent on the sample chosen.
It was also concluded that tne chance of conductor insulation damage was probably smaller during rework than during original cabling and jacketing although rejacketing causes an additional increment of stress to the conductors. FRC does not recommend that LOCA tests be performed on the specific cables involved in this inspection; however, FRC recommends that the NRC give consideration to LOCA testing of rejacketed cable since the rejacketing process entails an incremental increase in stress to the conductors that has not been included in LOCA test results to date.
It is recognized that such tests are out of the scope of this investigation. A=-
. F*enkhn Res,eerth Center
,