ML20086M077

Forwards Plant Response to NRC RAI Re Previous Responses to GL 92-08 on Thermo-Lag 330 Fire Barriers

ML20086M077
Person / Time
Site:	Oyster Creek
Issue date:	07/17/1995
From:	J. J. Barton GENERAL PUBLIC UTILITIES CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
C321-95-2184, GL-92-08, GL-92-8, NUDOCS 9507240104
Download: ML20086M077 (11)

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. l GPtJ Nuclear Corporation

. Nuclear  :::eit:388 Forked River. New Jersey 08731-0388 609 971-4000 Writer's Direct Dial Number:

C321-95-2184 July 17,1995 U. S. Nuclear Regulatory Commission Att: Document Control Desk Washington, DC 20555

Subject:

Oyster Creek Nuclear Generating Station (OCNGS)

Docket No. 50-219 Response to the Follow-Up to the Request for AdditionalInformation Regarding Generic Letter (GL) 92-08 NRC letter dated May 24,1995, requested additional detailed information regarding previous OCNGS responses to GL 92-08 follow-up requests for additional information which were submitted to NRC on December 27,1994 and March 31,1995. These submittals were in '

response to NRC follow-up requests for additional information dated September 15,1994 and December 29,1994.

The Attachment provides a detailed response to NRC letter dated May 24,1995 based on the present OCNGS plan of action to resolve the Thermo-Lag issue. Resolution of this issue for OCNGS is presently dependent on NEI and EPRI activities the outcome of which could affect the OCNGS resolution schedule as well as the individual steps to resolution. It is our intent to advise NRC of changes to the intended program for resolution, if they occur.

Si erely,

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!f J. I. on, o President and Director, O cr Creek JJB/DJD/ pip Attachment c: Administrator, Region 1 Oyster Creek NRC Resident Inspector Oyster Creek NRC Project Manager A. Marion - NEl 9507240104 950717 PDR ADOCK 05000219 g/f

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'"l GPU Nuclear Corporation is a subsidiary of Genera! Pubhc Utihties Corporation 'f

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. i Response to the Follow-Up to the Request for Additional Information Regarding  !

Generic Letter (GL) 92-08 i

1.0 Reouests for Additional Information (RAI) of September 1994 (1) The RAI dated September 15, 1994, requested information regarding important I barrier parameters, Thermo-12g barriers outside the scope of the NEI program, ampacity derating, alternatives and schedules. In its responses of December 27, 1994, GPU Nuclear Corporation (GPU Nuclear, the licensee) did not submit its schedules for completing corrective actions necessary for the resolution of the Thermo-Lag issues at Oyster Creek. A schedule for the completion of all corrective actions is required.

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Response

GPU Nuclear letter dated December 27,1994 (C321-94-2279), Attachment 1, j Response item VI.4 identified that evaluations of the unacceptable Thermo-Lag 1 barrier configurations would be completed by December 31,1995. The walkdowns, l inspections, reviews and analysis required to support completion of these evaluations  ;

has bee's and continues to be aggressively pursued by GPU Nuclear using in-house 1 resource; and the completion date of December 31,1995 is expected to be met. The results of tnis evaluation effort will identify the appropriate final resolution for each l of the individual barrier configurations as previously identified in GPU Nuclear letter j dated December 27,1994. An integrated schedule for implementation of corrective actions is not available as the evaluation efforts must first be completed. GPU  !

Nuclear will identify the planned final resolution, and corresponding implementation schedule, for all existing OCNGS Thermo-Lag fire barriers by December 31,1995, consistent with completion of the evaluations described above. It is our intent to achieve final resolution of this issue and implement identified corrective actions no later than December 31,1998. This is based upon resolution of scope as a result of  ;

our submittal scheduled for December 31,1995 and obtaining NRC approval by mid-1996. Any upgrades or modifications will be scheduled in accordance with the Long Range Planning Program Integmted Schedule pursuant to License DPR-16, Condition 2.c.(6).

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Attachment Page 2 l

(2) In its responses of December 27,1994, the licensee stated that it will request exemptions for some Thermo-Lag installations based upon fire modeling or probabilistic safety analysis (PSA). In the RAls of September 1994, the NRC staff provided the NRC position regarding the use of performance-based approaches, such as fire modeling and PSA, for resolution of the Thermo-Lag issue and included the l staff guidance on the technical information required to support exemption requests.

The licensee should submit additional information concerning the application of fire modeling and PSA to the resolution of the Thermo-I2g issue at Oyster Creek.

Response

GPU Nuclear is a participant in the EPRI Tailored Collaboration effort which has developed methods for evaluating Cable Wrap Fire Barrier Performance. GPU Nuclear representatives were in attendance at the detailed presentation made to the NRC staff on April 25,1995 by Florida Power Corporation on the development and use of these tools. GPU Nuclear intends to make use of two of the three tools (Fire llazard Tool and Performance Rating Tool) to provide an additional and quantifiable perspective to augment the traditional qualitative approach for exemption requests and strengthen the basis for exemption requests where more complex fire hazards analysis problems exist. GPU Nuclear does not intend to use fire modeling as the sole basis l for an exemption request. Fire modeling provides useful insights by creating localized fire scenarios because these types of scenarios are more realistic. When put I into perspective with the traditional qualitative approach of assuming consumption of all combustibles in an area, fire modeling assists in judging the adequacy of fire protection features including Thermo-Lag cable raceways. The detailed methodology I for use of fire modeling will be included as part of our planned submittals scheduled for December 31,1995, which will identify the final resolution for each Thermo-Lag fire barrier configuration, as described in Item A above.

It should be noted that GPU Nuclear is not currently planning to use probabilistic safety analysis as a supporting basis for exemptions associated with resolution of the Thermo-Lag issue.

2.0 Reouests for Additional Information of December 29.1994 (1) The licensee stated that it cannot provide a response to portions of Section 1.a of the RAI without agreement between the Nuclear Energy institute (NEI) and the NRC. In  !

Section 1.a, the NRC staff requested information describing the specific tests and analyses to be performed on Thermo-Lag materials that are installed at Oyster Creek.

In Section 1.c, the NRC staff requested licensees to submit a schedule for verifying Thermo-Lag materials. In its response, the licensee stated that it would not submit

4 Attachment Pa'ge 3 a schedule until 30 days after notification of an agreement between NEI and NRC. In a public meeting with the four (4) Thermo-12g " lead plants" on March 14, 1995, concerning the December 1994, letters, which was attended by GPU Nuclear representatives, the NRC staff stated that licensees were expected to be fully responsive to the RAI and that it would not grant extensions to the 90-day response period. Moreover, with the exception of the .NEl generic chemical composition program, there are no Thermo-lag issues under discussion between the NRC staff and NEl. The licensee should submit the information requested by the NRC staff in its RAI of L)ecember 29,1994.

In its responses to Section 1.a(2), " Material Thickness," and Section 1.a(4), " Voids, Cracks, Delaminations," the licensee stated that based on receipt inspection and field repairs that no additional consideration will be given to these parameters. Section 2.b of the enclosure of the RAI required licensees to describe the methodology to be applied to determine the number and type of representative installed barriers to be examined in detail to ensure that the materials and important parameters used to construct the in plant barriers are representative of the fire endurance test specimens.

The licensee's response to Section 2.b stated that GPU Nuclear considers the quality control applied to the original installation as adequate to permit verification by review of installation documents for barrier parameters not visible by walkdown and does not plan to perform any further destructive examination of installed barriers. In the RAls the staff stated that some of the important installation parameters cannot be determined by plant walk-downs or by comparing installed barriers with installation records or procedures used to construct the barriers. These parameters can only be verified by detailed examination such as disassembling a representative sample of in-plant barrier configurations. The licensee must have valid and verifiable information on each of the important parameters if it intends to rely on Thermo-Lag for meeting -

NRC fire protection requirements. This position was re-stated by the staff at the March 14,1995, public meeting in response to a question and documented in the meeting summary dated March 28,1995. The licensee should submit the information requested by the NRC staff in its RAI of December 29,1994.

Response

Our response to the first paragraph above is provided in the response to item 2.(3) on i page 9 of this attachment.

i As stated in GPU Nuclear letter (C321-95-2114), dated March 31,1995, GPU Nuclear considers the quality control applied to receipt and installation of Thermo-Lag material as adequate assurance to permit verification of relevant parameters not visible in walkdowns through the extensive installation inspection documentation. Detailed

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quality control records, for both receipt and installation, document and demonstrate p conformance to fire endurance test specimens. GPU Nuclear established an inspection t

and surveillance plan for receipt inspection of preshaped conduit sections,

. prefabricated panels, flexi-blanket, and trowel grade subliming material. Receipt inspections were performed by GPU Nuclear inspection personnel, not a thiirl party inspection group. Receipt records show conformance of the materials to Thermal-Science Incorporated (TSI) specifications for thickness (based on fire rating), shape (conduit wrap or flat boards), and material consistency (lack of visible voids, enicks and damage). Overall, a reject rate of approximately 40% was obtained during these receipt inspections and resulted in the establishment of a source manufacturing

, inspection effort. The inspection and surveillance plan provided quality control on-site receipt inspection requirements pertaining to physical damage and manufacturing deviations, documentation, and sample inspection. Each item is addressed below.

1. Receipt Inspection for Physical Damage and Manufacturing Deviations:

a. The following criteria were used for Preshaped Conduit Sections and Prefabricated Panels.

i. There was to be no cnishing or separation of skin from the inner lining.

ii. Coatings (on all surfaces) were not to appear to be chipped or peeling and were not to be separated fmm inner insulation.

Coatings could be repaired in accordance with manufacturer's instructions. On site repair.was performed if the repair was minor, otherwise the material was returned to the vendor.

1 For three hour rated conduit sections a split in the outside skm greater than 1" long was cause for rejection.

iii. Thickness was to be as follows:

a. Half Hour Rated - 0.25" to 0.45"

b. One Hour Rated - 0.625 +/- 0.125"

c. Three Hour Rated - 1.250 +/- 0.250" The measurements taken on all prefonned conduit items were 3 measurements on each edge of the half round preshaped conduit

and 3 measurements down the center (a total of 9 l measurements). Thickness measurements for each panel were l taken at various areas on each side and some measurements I

toward the center (a total of 12 measurements per panel).

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Attachment

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iv. Voids in exposed cross-sectional surfaces were not to result in the material being less than the minimum thickness in depth or .

the width of the void being one half the minimum thickness. To clarify this requirement, if the Thermo-Lag item was One Hour material, the thickness of the Thermo-Lag was required to be no less than 0.5". The void could not reduce the thickness of the material less than the 0.5". The inspector also verified that the width of the void could not be wider than 0.25". Plant Quality Control Inspectors also verified the absence of voids during their inspection of the barrier installations. This verification is documented on the individual Quality Control Plant Inspection Report for each Fire Barrier Envelop system.

b. The following criteria were used for Trowel Grade Subliming Material.

i. Maintain material within required temperature limits.

Temperature readings were to be between 32 degrees F and 100 degrees F.

ii. The shelf life was verified to ensure that once received, the trowel grade material could be installed.

c. The following criterion was used for Flexi-Blanket (Thermo-Lag 330-660) Material.

i. there was to be no obvious physical damage - punctures, tears, etc.

2. Documentation:

a. Verification that the documentation required by the Material Specification had been received and accepted by Engineering.

b. Verification that the Manufacturer Application Procedures were included with the shipment and were acceptable to Engineering.

c. Verification that the GPU Nuclear Manufacturing Assurance Inspector's report on Thermo-Lag items inspected at the TSI factory were included with the shipment.

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3. Sample inspection (Source and Site):

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a. Source Material and testing set-ups were inspected at the TSI 1 factory by GPU Nuclear Manufacturing Assurance inspection personnel. They utilized the sites' l

Inspection / Surveillance Plan criteria for performing their inspections of materials prior to shipment. They also performed checks of the manufacturing processes to l supplement the manufacturer's program and assist the site in receiving more consistent products.

b. Site Materials received on site were inspected to the pre-established (and engineering approved) Inspection Plans.

These plans established acceptance criteria for the specific material being inspected. They also included sampling plans allowing inspection of a reduced population once a sufficient confidence level was attained I (100% acceptance). This option was never fully implemented for the TSI Preformed Thermo-Lag materials due to the number of defects identified. This )

information and these Inspection Plans were then passed l on to TMI to support their modification work with this  ;

vendor.

Installation inspection work was also performed by GPUN inspection personnel not a third party inspection group. These inspectors had received training as Thermo-Lag installers. Installation checklists document traceability to those acceptable materials received, that the workers were certified Thermo-Lag installers, barrier section

' buttering', sealing of any gaps or holes to the fire rated thickness, alignment of i barrier sections, banding and band spacing. Interface connections with fire barriers are also protected for the required distances and at the proper rating, sealing of protuberances to the same fire rating requirements, and that work was performed to engineering and work documents (which were verified daily for revision). Installation questions were identified to engineering, their resolution documented and implementation verified in the field.

Atta,chme.nt Pa'ge 7 The controls established by GPU Nuclear on TSI provide adequate assurance that only as-specified Thermo-Lag items were utilized at OCNGS. This effort assumed that if material consistency and thickness were acceptable, then the material was acceptable for use. During the fabrication of the Fire Barrier Envelope System in the plant, any voids that were exposed after cutting the Thermo-Lag material were repaired prior to assembly.

Additionally, OCNGS has completed the destructive examination of an installed 3-hour Thermo-Lag conduit wrap fire barrier to verify parameters not visible by walkdown. This barrier was installed in 1984. Disassembly of this barrier determined that the outside was " buttered" with trowel grade, edges, and ends were aligned, the inner and outer stress skins for a 3-hour rating were in place, material thickness exceeded the minimum required, the banding spacing, which had been set at 6 inches was found to be a nominal 5 inches, and no voids or laminations were noted either internally or externally, or in the perpendicular cut areas.

Based on procurement records there were only two periods of Thermo-Lag installation at OC. The first period of performance was in 1984 (10th refueling outage), and comprised only the above mentioned and inspected barrier which we recently destructively examined. This barrier material was not subject to source inspection nor to installation QC inspection requirements established for the later installations. The  ;

second period of performance was in 1986/87 (lith refueling outage) for which l GPUN established the formalized inspection processes (detailed above) which included extensive, documented source, receipt and installation checks. This second period was the bulk of the Thermo-Lag installations for Appendix R. There have been two subsequent purchases for minor repair materials (5 gallon buckets of trowel grade Thermo-Lag and stainless steel banding) to date. Since the barrier that was not  !

subject to a formalized inspection process at the time of installation has been verified to have met the appropriate specification requirements, GPUN believes that the above described destructive testing and established quality control plans adequately demonstrate that the installations at Oyster Creek conform to GPUN Engineering and TSI specifications.

I Overall, the GPU Nuclear Operational QA Plan verified the integrity of the materials l and the installation of 10 CFR 50 Appendix R modifications. The actions described above are appropriate and sufficient for verification of the important parameters which could not be verified by field walkdowns. GPUN has concluded that detailed examination of parameters which rely on existing procurement and installation records is a valid means of establishing the installed configuration of Thermo-Lag raceways at Oyster Creek and that no additional examinations need to be performed. Further verification of active fire barriers by destructive disassembly will needlessly incur the additional costs of procuring replacement parts and materials, certifying new installers, and additional radiation exposure for both disassembly and reassembly.

s Attachment Pa*ge 8 (2) In its response to Section 1.a.(6), " Combustibility" and Section 1.a(7), " Flame Spread," the licensee stated that the NEI program is adequate for establishing combustibility and Dame spread. In Information Notice 92-82, "Results of Thermo-Lag 330-1 Combustibility Testing," the staff provided the results of combustibility testing performed by the National Institute of Standards and Technology, which determined that Thermo-Lag 330-1 is combustible material. In addition, in a letter to NEI dated March 13, 1995, the NRC staff informed NEI that its methodology for evaluating Thermo-Lag combustibility does not provide a level of safety equivalent to that specified by existing NRC fire protection requirements and that the NRC staff would not accept the use of the NEI guide to justify the use of Thermo-Lag where noncombustible materials are specified by NRC fire protection requirements or to assess the combustibility of Thermo-Lag. This information was also discussed by the NRC staff at the March 14,1995, public meeting. Flame spread testing of Thermo-Lag was not included in the NEI program. The licensee should submit the information requested by the NRC staff in its RAI of December 29,1994.

Response

We believe clarification of our response on March 31, 1995 is required. The request in the RAI of December 29,1994 was to describe the " specific tests and analyses that will be performed to verify that the Thermo-Lag fire barrier materials that are currently installed at OCNGS or that will be installed in the future, are representative of the materials that were used to address the technical issues associated with Thermo-Lag barriers..." GPU Nuclear's response on March 31, 1995 stated that "the NEI program is adequate for establishing combustibility and flame spread ratings (pending evaluation of chemical testing results)." Combustibility and Dame spread rating test results as provided to the NRC in NUM ARC's letter of October 12,1993 are considered adequate for establishing these material properties. The NUMARC Fire Test Program included ASTM E1321 (lateral Game spread) and ASTM E1354 (heat of combustion) tests performed independently at Underwriter's Laboratories. The results of these tests were provided to the NRC as attachments to NUMARC's letter of October 12,1993 as supporting documentation for the Thermo-Lag 330-1 Combustibility Evaluation Methodology Plant Screening Guide. The NRC has recently recognized and referenced the results of this testing in enclosure 2, to Attachment 1, of Information Notice 95-27; the NRC's review of the aforementioned guide. Although NRC has not endorsed the methodology presented in the NEI guide, neither the specific testing method nor the testing results have been in question.

GPUN believes the combustibility and Game spread test results are adequate for establishing these two material propenies. Assuming wide spread chemical testing provides assurance of chemical consistency, those test results can be applied to Thermo-Lag installed at OCNGS and combustibility and Dame spread need not be reconfirmed by plant specific testing. I

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Atta.chment Pa*ge 9 GPU Nuclear will reassess the need for OCNGS specific combustibility and flame spread testing should the NEl sponsored consistency program prove unsuccessful in I demonstrating chemical consistency.

l Additionally, it should be noted that GPU Nuclear recognizes Thermo-Lag as a j combustible material. The Thermo-Lag material has been included as part of the  !

combustible loading inventory maintained for the OCNGS Fire Hazards Analysis Repon. Thermo-Lag material is also considered as a combustible material for ongoing fire modeling evaluations where applicable.

l (3) In Section 1.b of the RAI, the NRC staff requested that the licensee describe the methodology that it will use to determine that the sample size of Thermo-Lag i materials to be considered is sufficient to assess the total in-plant population. In its ,

response, the licensee stated that it will not provide a plant specific program to  !

address this question. The licensee should submit the information requested by the NRC staff in its RAI of December 29,1994.

Re_soonse GPU Nuclear is currently participating in the NEl sponsored chemical test program ,

intended to establish similarity between the materials previously tested as part of the NEl fire barrier test program and the materials installed at OCNGS. Since our last letter on this issue, we have submitted Thermo-Lag samples for analysis consistent with NEl's instructions. The OCNGS Thermo-Lag samples were taken from four (4) locations for chemical analysis. Each sample and location was identified and individually packaged to prevent cross contamination. The results show that the chemical composition of the OCNGS samples are consistent with those materials tested as part of the NEl fire barrier test program based upon a preliminary evaluation ,

of the results as reported to GPU Nuclear by NUCON. GPU Nuclear will submit a l report addressing these results along with the industry-wide results being coordinated by NEI by November 1,1995. This date is based upon NEl's expectation of releasing industry-wide sampling results by the end of July 1995.

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Attachment Pai;e 10 Knowledge of the industry-wide results will provide a basis to confirm applicability of generic industry data with respect to fire endurance capability, combustibility and flame spread rating (see also our clariHcation with respect to combustibility and flame spread rating described above). In addition to the aforementioned characteristics, GPU Nuclear is also currently independently evaluating the appropriate mechanical properties of Thenno-Lag. The results of this evaluation and its applicability to installed conHgurations at OCNGS will be included in the November 1,1995 report.

Based on the industry wide sampling conducted by NEI, GPUN expects that the consistency of the material's chemical composition will be established. The significance of the size of both the OCNGS and industry-wide sample population will be included in the repon to be submitted by November 1,1995.

(4) In Section 2.d of the RAI (cover letter also refers to Section 2.c " Schedule"), the NRC staff requested that the licensee submit a written repon confirming the completion of the verification effort and the results of the detailed examinations. In it's response for Oyster Creek, the licensee stated that it does not plan to perfonn any additional verification of barrier parameters at this time. The licensee should submit the infonnation requested by the NRC staff in its RAI of December 29,1994.

Resoonse We believe a clarification of our response on March 31,1995 is required. GPU Nuclear will submit a Topical Report by December 31,1995 which will document the Thenno-Lag barrier evaluations currently being perfonned. This repon will provide the detailed basis and methodology that has been applied for each barrier configuration to determine the important barrier parameters and to verify that the panuneters of in-plant configurations are representative of the parameters of the NEI fire endurance test specimens.

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