ML20009H123
| ML20009H123 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 07/24/1981 |
| From: | Palladino N NRC COMMISSION (OCM) |
| To: | Udall M HOUSE OF REP., INTERIOR & INSULAR AFFAIRS |
| Shared Package | |
| ML20009H124 | List: |
| References | |
| NUDOCS 8108060068 | |
| Download: ML20009H123 (7) | |
Text
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- KE "he UNITED STATES U
S NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20666
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Affg cFFICE OF THE M h.I h
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CHAIRMAN The Hdnorable Morris K. Udall, Chairman b k
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Comittee on Interior and Insular AffadrY U.S. House of Representatives 9_
JUL 2 91981 > g Washington, D.C.
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Dear Mr. Chaiman:
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\\ P This is in response to yaur letter dated May
, in which you high-lighted three items of concern:
(1) the serious allegations made by Mr. Fred Slautterback to Congressman Panetta to the effect that the Flamtrol cable installed at the Brunswick nuclear power facility does not comply with NRC requirements; (2) your view to the effect that the allegations hava not 4
been addressed adequately by the NRC; and (3) your belief that the Conaission should undertake :o determine in detail the basis for the NRC staff's r
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conclusion that Flamtrol cable, installed at Brunswick and other licensed
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nuclear power plants, complies with the Comission's requirements.
.he concerns expressed in your letter are addressed in the enclosed Inspection and Enforcement (IE) report.
The information in the IE report 4
i and its attachments describe the basis for the technical determinations to date that the Flamtrol cable being used at Brunswick and other nuclear-j power facilities complies with tL4 applicable NRC requirements.
However, IE is continuing its review of the matter.
In support of this i
review, on May 18, 1981, IE contracted with the Franklin Institute Research Laboratories (FIRL) to make a cc,nfimatory technical assessment of the.use of Flamtrol cable.
FIRL did some of the original environmental qualificativ.:
and electrical tests of the Flamtrol cable for the licensee and for Raychem.
i This confirmatory technical assessment will be accomplished as described in the enclosed FIRL proposed statement of work. We expect this assessment to be completed within the next three months, and if the conclusions reached are different than those expressed in this letter, we will initiate appropriate j
actions and inform you of same. We will also provide you with a copy of the l
FIRL report upon its completion.
4 I sincerely hope that 'his iriformation acceptably addresses and allays the j
concerns expressed in your letter.
j Sincerely, (l
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Nunzio PL adino l
Chairman
Enclosures:
- l. IE P.n, ort w/ attachments
- 2. FIRL Proposed Statement of Work cc:
Rep. Panetta'(w/encis) 8108060068 8107541 PDR COMMS NRCC CORRESPONDENCE PDR
e REPORT BY NRC'S OFFICE OF INSPECTION AND ENFORCEMENT ON i
CONGRESSMAN UDALL'S LETTER TO CHAIRMAN JC1EPH HENDRIE DATED MAY 28, 1981 (ALLEGATIONS REGARDING THE USE OF RAYCHEM-FLAMTROL CABLE IN NUCLEAR POWER PLANTS Scope:
Congressman Udall's letter to Chairman Hendrie expressed three items of concern:
(1) the serious allegations made by Mr. Fred Slautterback to Congressman Panetta (and others) to the effect that Raychem-Flamtrol (trademark) cable installed at the Brunswick nuclear power facility does not comply with NRC requirements; (2) his view to the effect that the allegations have not been addressed adequately by the NRC; and (3) his belief that the Comission should undertake to determine in detail the basis for the NRC staff's conclusion that Flamtrol cable, installed at Brunswick and other licensed nuclear power plants, complies with the Commission's requirements.
Background:
The following background infomation is presented to put in better perspective Mr. Slautterback's allegations regarding Flamtrol cable.
The applicable NRC requirements for cables and other components used in nuclear power plants are contained in Gener&l Design Criterion (GDC) 1, " Quality Standards and Records,"
of Appendix A to 10 CFR Part 50, and in Criterion III, " Design Control" of Appendix B to 10 CFR Part 50.
GDC 1 requires that components important to safety be fabricated to quality standards commensurate with the importance of the safety functions to be performed.
However, it provides no sper.ific guid-ance with respect to acceptable standards.
In the absence of specific NRC guidance, it is common practice for utilities to use industry codes and standards as a means for complying with applicable NRC criteria.
IEEE Std 383-1974, "IEEE Standard for Type Test of Class IE Electric Cables, Field Splices, and Connections for Nuclear Power Generating Station," is being accepted by the staff for cable qualification purposes; however, it did not exist at the time the Brunswick cable was purchased.
Nevertheless, identical cables were subsequently qualified by Raychem Corporation to the requirements of this standard.
In fact, Flamtrol cables were qualified to perform under certain conditions more stringent than those in IEEE Std 383-1974 For example, it is important for cables used in nuclear power plant applict. tion to not propagate fires by having an " instant out" characteristic. Toward this end, the Flamtrol cable was qualified to pass a 210,000 Btu /hr vertical cable tray flame test without releasing significant amounts of corrosive or acidic gas when subjected to fire.
In addition, Flamtrol cables were tested at flame intensities of 400,000 Btu /hr and did not propagate the test flame.
In contrast, the accepted industry standard for cables used in nuclear power plants is a 70,000 Btu /hr flame.
. Enclosure 1 In late 1974 or early 1975, Mr. Slautterback first observed that certh.
individual component wires, when removed from the complete cable assemolies, exhibited lower ac dielectric withstand voltages than they had exhibited as individual component wires prior to their being assembled into cables. Mr.
Slautterback informed Raychem, various utilities, and NRC of Ms observations.
l As a result, several actions were initiated, including testi.; for and research-l ing into the causes for such changes by Raychem Corporation; re/iewing and evaluating the test results and specification requirements by the affected utilities and their consultants; testing of complete cable assemblies being used at the Brunswick facility by Franklin Institute Research Laboratories; and investigating the Slautterback allegatiens by the Office of Inspection and Enforcement. These activities confirmed Mr. Slautterback's observation that some component wires, when removed from their unshielded multiple conductor cable assemblies, exhibited lower electrical insulating characteristics than they exhibited prior to being assembled into multicanductor cable assemblies.
It was subsequently determined that this phenomenon is limited to cables having a combined insulation thickness (i.e., the insulation of the individual wire plus that of the cable's outer cover or jacket) of 0.120 inch (120 mils) or greater. The cause of this phenomenon has been detennined to be due to a
" space charge" effect. This space charge effect is associated with the manu-facturing process used in cross-linking the Flamtrol cable.
In this process, tne cable materials are cross-linked by exposing them to an electron beam radiation source having an energy level of 2 Mev.
If the total thickness of the dielectric material to be cross-linked is greater than 120 mils, then the 2 Mev source does not provide sufficient energy for developing an ionized conducting path to ground for the electrons.
In such cases, a space charge will build up which affects the individual component wire's insulating char-acteristics. Thus, for cables having a combined insulation thickness of 120 mils or more, the energy level must be raised to eliminate the likelihood of space charges (e.g., raising the energy level from 2 to 3 Mev eliminated this effect of Raychem cables having a combined insulation thickness greater than l
120 mils.)
Although the aforementioned tests confirmed a change in individual wire insulating characteristics, they also confirmed that the complete Brunswick cable assemblies (i.e., the individual wires with the outer jackets in place) met the specified ac and de dielectric withstand requirements as well as the insulation resistance (IR) requirements.
Response to Items (1) and (3)--These items concern the allegation that the cable installed at Brunswick does not comply with NRC requirements. As previously stated, the NRC's requirements for cables are contained in general terms in Appendix A, " General Design Criteria for Nuclear Power Plants," and in Appendix B,
" Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants" to 10 CFR Part 50. The applicant uses the requirements contained in these criteria in conjunction with the applicable design bases in his license application to develop specific requirements for the purchase of cable. Thus, although the requirements specified by the applicant must be sufficiently conservative to conform with NRC criteria, they are often more conservative (e.g., the flame resistance for Flamtrol cable).
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. Enclosure 1 It is common practice to use existing industry codes or standards to provide assurance that a purchased component is suitable for its intended function.
One parameter often evaluated by industry standards is moisture resistance of cables. The measurement of this parameter is usually obtained by an accelerated water absorption test, the criterion of which is the basis of Mr. Slautterback's allegations.
No industry standard existed then (or now) for tha " water absorption criterion" to be used in evaluating radiation cross-linked polyethylene cable used at the Brunswick facility.
In lieu of such a criterion, i conservative value was specified that the manufacturer was reasonably sure the cable would meet but, in fact, did not. This criterion was subsequently changed to a value deemed by the utilities to be both realistic and sufficiently conservative to assure that the cable would perform its intended function.
1 Criterion XV, "Nonconfonning Materials, Parts, or Components", of Appendix B to 10 CFR Part 50 requires that nonconforming parts be reviewed and accepted, rejected, repaired or reworked in accordance with documented procedures. As a result, one utility chose to reject a substantial amount of cable, whereas the other utilities accepted the cable based on the results of their review and the additional tests.
We reviewed the actions taken by the utilities and concluded:
(1) that the revised water absorption criterion provided acceptable assurance that the cables could perform their intended function, and (2) that the actions taken were in conformance with the provisions of Criterion XV.
In contrast Mr. Slautterback alleged that since the cable failed to meet a specified requirement, the cable did not camp / with NRC requirements.
It seems that Mr. Slautterback is under the impr ssion that if a component does not meet all the requirements stipulated in the purchase specification, NRC requirements are not complied with, regardless of the safety implications of the discrepancy or of the initial conservatism in the specification.
In summary, means acceptable to the staff for disposing of nonconforming parts include reviewing the effect of the nonconformance on the part's ability to 3
l perform its intended function, after which the part may be accepted, rejected, repaired or reworked, as appropriate.
In this case, one utility (Pacific Gas and Electric) chose to remove approximately 150,000 ft of Flamtrol cable from moisture prone conduits in its Diablo Canyon Unit 1 facility, while the other utilities chose to use the cable. On the one hand, although the rejection was instituted without pressure from the NRC, it was made before the matter had been completely reviewed. On the other hand, those that opted to use the cable did so after reviewing the matter and determining the cable was accept-able for its intended function.
Based on the foregoing, it is our view that Flamtrol cable is acceptable for use in its intended application at the Brunswick facility and other licensed nuclear power plants.
Response to Items (2) and (3)--These items pertain to whether NRC adequately addressed the allegations. As stated previously, the allegations made by Mr. Slautterback initiated several parallel and independent actions.
These actions 4
included investigations into the allegations; inspections of the cable and its installation at the various facilities; evaluations and reviews of the technical i
. Enclosure 1 l
aspects of using the cable; examinations of the quality _ assurance progr2ms at Raychem Corporation and at the various facilities; and reviews by Inspection and Enforcement personnel to assure that the actions being taken by the appli-cants and Raychem Corporation were appropriate to the disposition of the matter.
Tests conducted to verify the acceptability of Flamtrol cable included thousands of measurements at Raychem Corporation, Carolina Power and Light Company's Brunswick facility, and Franklin Institute Research Laboratories.
The results of these tests are included in (1) a summary report by Raychem Corporation dated May 6, 1976, and (2) a Franklin Institute Research Labor-l l
atories (FIRL) report (F-C4408).
A copy of each report is attached to this report.
The FIRL tests were conducted on complete cable assemblies by first immersing approximately 12 ft of a 15 ft cable assembly in water for approx-imately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after which the assembly was tested while still immersed in water.
The ac and dc dielectric withstand tests consisted of applying 5.6 kVac and 16.5 kVdc each for five minutes without dielectric breakdown.
The insulation resistance (IR) test measured the cable's resistance by using a 500 Vdc meggar.
Although the industry standard for the IR test is 10,000 megohms-1000 feet, all Ik measurements exceeded the manfacturer's acceptance value of 20,000 meghems-1000 ft.
Evaluations of these tests and associated technical analyses led the NRC to concPide that the cable was acceptable for use at the Brunswick nuclear facility.
Additional tests were subsequently performed by Raychem Corporation and documented in a report entitled, " Final Report:
Tests of Raychem-Flamtrol Cable for Use in Service Conditions of AC Voltage and Long Term Water Immersion", dated 29 July 1977.
The results of these final tests sub-stantiated our original conclusion that the cable was acceptable for use at the Brunswick nuclear facility as well as at other nuclear installations.
A copy of this report is also attached to this report.
In addition to the aforementiored tests, Carolina Power and Light Company implemented a long-term cable surveillance program at its Brunswick facility in 1977.
The program consists of taking insulation resistance measurements on spare cables annually.
The cables selected for this program include at least one of each type of cable used in safety related applications at Brunswick.
The total number of individual wires tested annually is 489, in 81 cable assemblies.
Although those tests are conducted with a 1000 volt meggar, no insulation breakdowns of the type described by Mr. Slautterback have occurred to date.
In light of the foregoing, we conclude that the matter related to the acceptability of using Flamtrol cable in nuclear power facilities has been adequately addressed by the NRC and that the cable is acceptable for use in its intended application.
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ATTACHMENTS TO ENCLOSURE 1 1.
Summary Report of Rayc. hem Flamtroi rable Review, 5/6/76 2.
Franklin Institute Research Laboratories Report (F-C4408), April 1976 3.
Final Report: Tests of Raychem-Flamtrol Cable for Use in Service under Conditions of A-C Voltage and Long-Term Water Immersion, T/29/77 3
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ATTACHMENTS TO ENCLOSURE 1 1.
Summary Report of Rayc. hem Flamtrol Cable Review, 5/6/76 2.
Franklin Institute Research Laboratories Report (F-C4408), April 1976 Tests of 'aychem-Flamtrol Cable for Use in Service 3.
Final Report:
d under Conditions of '-C Voltage and Long-Term Water Immersion, 7/29/77 l
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