3F0195-03, Forwards Response to follow-up to RAI on GL 92-08, Thermo- Lag Fire Barriers, Per 10CFR50.54(f)

Forwards Response to follow-up to RAI on GL 92-08, Thermo- Lag Fire Barriers, Per 10CFR50.54(f)

ML20077M975
Person / Time
Site:	Crystal River
Issue date:	01/06/1995
From:	Boldt G FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
3F0195-03, 3F195-3, GL-92-08, GL-92-8, NUDOCS 9501130237
Download: ML20077M975 (17)

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Florida Power CORPORATION maan mm January 6, 1995 3F0195-03 U. S. Nuclear Regulatory Ccmmission Attention: Document Control Desk Washington, DC 20555

Subject:

Response to Follow-up to the Request for Additional Information on Generic Letter 92-08, "Thermo-Lag Fire Barriers," Pursuant to 10 CFR 50.54(f)

Reference:

A.

FPC to NRC letter, 3F1094-10, dated October 31, 1994 B.

NRC to FPC letter, 3N0994-17, dated September 23, 1994 C.

FPC to NRC letter, 3F0294-15, dated February 9, 1994 D.

NRC to FPC letter, 3N1293-36, dated December 22, 1993

Dear Sir:

The Nuclear Regulatory Commission (NRC), in Reference D, requested information regarding the configurations and amounts of Thermo-Lag 330-1 fire barriers installed at Crystal River Unit 3 (CR-3) and the cable loadings within particular Therino-Lag configurations in accordance with the provisions of 10 CFR 50.54(f).

The request stated that this information was needed to review NUMARC's (now NEI) guidance for applying test results to plant-specific configurations and to identify fire barrier configurations that are outside the scope of the NEI program.

In addition, for those configurations that were not bounded by the NEI test program or those configurations that Florida Power Corporation (FPC) deemed impractical to upgrade, it was requested that plans and schedules for resolving the associated technical issues identified in Generic Letter 92-08 also be provided.

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U. S. Nuclear Regulatory Commission 3F0195-03 Page 2 of 17 In Reference C,

Florida Power Corporation provided a response based on information available from plant documentation reviews and fire barrier walkdowns.

Both of these activities were in progress but not complete at that time, therefore the information provided did not entirely fulfill your request.

Additionally, the NEI Thermo-Lag fire barrier endurance test program was not completed, so a clear description of how we proposed to use the test results was not possible.

In Reference B, the Nuclear Regulatory Commission acknowledged the receipt of this information, and noted that with the completion of the NEI test program, FPC is now required to submit the information which was incomplete in our previous response. Reference B further provided information on the NRC's intended course of action to resolve the Thermo-Lag issue along with guidance on the use and justification of exemptions where it can be demonstrated that in-plant conditions provide an adequate level of fire safety.

In Reference B you requested that FPC revise our response to Section V of Reference D.

We have eviewed Section V of our response, and believe that we have given the staff an incorrect impression that FPC would be relying on probabilistic methods to justify Appendix R exemptions.

Our intention is to pursue exemptions where we can technically justify them. FPC will use deterministic methods to demonstrate that our installed barriers provide protection that exceeds the hazards in a given fire area.

This approach meets the guidance referenced above on submittal of exemptions. We discussed our approach and its reliance on deterministic modelling with the staff on November 15, 1994 during the pilot plant inspection of Crystal River.

Based on that discussion we feel this is still a valid option.

This letter and its attachments supersede and replace the information provided in Reference C in its entirety.

Sincerely, b

G. L. Boldt Vice President Nuclear Production GLB/SCP:ff Attachments xc: Regional Administrator, Region 11 NRR Project Manager Senior Resident Inspector

U. S. Nuclear Regulatory Commission 3F0195-03 Page 3 of 17 i

STATE OF FLORIDA COUNTY OF CITRUS 1

G. L. Boldt states that he is the Vice President, Nuclear Production for Florida Power Corporation; that he is authorized on the part of said company to sign and i

file with the Nuclear Regulatory Commission the information attached hereto; and that all such statements made and matters set forth therein are true and correct to the best of his knowledge, information, and belief.

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G. L. Boldt Vice President Nuclear Production Subscribed and sworn to before me, a Notary Public in and for the State and County above named, this 6th day of January, 1995.

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4 U. S. Nuclear Regulatory Commission 3F0195-03 Page 4 of 17 Response to the Follow-up to the Request for Additional Information Regarding Generic Letter 92-08 "Thermo-Lag 330-1 Fire Barriers" Florida Power Corporation's response to Reference D was based on the assumption that a majority of Thermo-Lag fire barriers installed at Crystal River Unit 3 (CR-3) could be bounded by the configurations included in the NEI Application Guide. Now that the Guide has been finalized, we have determined that many of our fire barriers are not bounded. Accordingly, we have revised our plans for resolving Thermo-Lag fire barrier issues. An overview of our approach describing the steps which will be used for resolution is provided below.

1 Evaluation of post-fire safe shutdown capability - A re-evaluation of the systems, equipment, and cabling necessary to achieve post-fire safe shutdown will be performed. This effort will attempt to identify additional shutdcwn methods and systems and/or fire area boundaries that if incorporated into the post-fire safe shutdown design would reduce the reliance on cable wraps; and, will attempt to iaentify alternatives to cable wraps as a means of ensuring post-fire safe shutdown capability.

The alternatives to be evaluated include new system alignments, pre-and post-fire operator actions, post fire repair activities, re-routing of cables, control circuit modifications, and back-up power sources. The additional shutdown methods and systems to be evaluated include all safety related and non-safety related systems capable of satisfying the Appendix R performance goals. Alternatives to be evaluated also include changes to the fire area boundaries, use of different fire areas / zones, 20 ft, separation zones, alternate barrier concepts and changes to active and passive fire protection features.

This effort will include a re-evaluation of the assumptions and constraints used in the original Appendix R analyses of CR-3's post-fire safe shutdown capability.

With respect to the assumptions used in the Appendix R analyses, we will no longer assume a loss of offsite power concurrent with a fire for those fire areas under the provisions of section III.G.2 of Appendix R.

It is also anticipated that application of knowledge gained from efforts such as Station Blackout and Emergency Operating Procedure development, will refine and reduce the list of equipment and circuits that require protection. Cable wrap fire barriers that are no longer needed will either be removed or retired in place.

Determination of qualified cable wrap fire barriers or barrier segments - The NEI Application Guide will be used to the extent possible to identify Thermo-Lag barrier configurations that can be bounded by test results, including barriers that were installed to support current exemptions. These will be demonstrated to be bounded by documentation of physical attributes and comparison to tested configurations. This process will use NEI test data (Phase 1 & 2), Texas Utility Electric Company (TVEC) test data, and Tennessee Valley Authority (TVA) test data. Where the protection afforded by these configurations does not meet the requirements of Appendix R, FPC will pursue corrective actions or exemptions as appropriate.

For fire barriers that are not bounded by the Application Guide, FPC will apply caterministic risk assessments and techniques as described below 1

to determine their effectiveness.

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s U. S. Nuclear Regulatory Commission 3F0195-03 Page 5.of 17 Evaluation of barriers or barrier segments which are not bounded by the Application Guide - FPC is-a ps.*ticipet in the EPRI Cable Wrap Fire Barrier

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Tailored-Collaboration (TC)..This project has been undertaken to supplement the use of the NEI Application Guide for utilities that cannot resolve all Thermo-Lag issues cost effectively through use of the Application Guide alone. FPC is one of 6 nuclear utilities currently participating with several others considering participation. The objective of this project is to develop analytical tools to assess the performance of safe shut down circuits protected with Thermo-Lag fire i

barriers.

The tools provide a means to quantitatively determine the cable or equipment protection provided by plant-unique barriers, under both ASTM E-119 and i

realistic fire exposures.

The tools rely heavily on the results of industry testing programs and on the NEI Applications Guide.

The specific tools are described below:

Barrier Rating Tool - This tool approximates the fire rating of installed cable wrap configurations under ASTM E-119 exposures.

The tool was r

developed using the NEI, TVA, and TV Thermo-Lag fire test data.

It uses observed Thermo-Lag behavior to predict the fire rating of untested configurations and calculates the total duration during which plant-unique cable will maintain its function.

Fire Hazard Tool - This tool predicts the fire exposure time / temperature history at installed Thermo-Lag locations.

The tool, an enhanced version of the fire modeling method developed under the EPRI Fire Induced Vulnerability Evaluation (FIVE), is designed for easy incorporation of IPEEE fire modeling data.

Barrier Performance Tool - This tool approximates the duration of cable protection provided by installed Thermo-Lag when subjected to the actual location dependent fire.

FPC will apply these tools in conjunction with fire modeling based on elements of the EPRI FIVE methodology to assess the level of protection, and damage potential to safe shutdown circuits and equipment that exists based on current plant specific conditions. The damage potential for the target shutdown feature will be established and a determination of acceptability of the installation will be made.

Based on these results an exemption may be pursued to accept the configuration 'as is.'

Alternately, a strategy for upgrading the combination of protective features that already exist may be developed to either support an exemption, or to bring the area into compliance with Appendix R,Section III.G.2.

Possible solutions that would be considered include:

Rerouting of safe shutdown circuits Adding detection or suppression to reduce needed barrier rating Barrier upgrade or replacement.

FPC is continuing to achieve interim compliance with fire protection requirements by periodic physical surveillance of Thermo-Lag cable wrap fire barriers in e

accordance with the requirements of our Fire Protection Plan.

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U. S. Nuclear Regulatory Commission 3F0195-03 Page 6 of 17 Response to the Follow-up to the Request for Additional Information Regarding Generic Letter 92-08 "Thermo-Lag 330-1 Fire Barriers" Thermo-Lag Fire Barrier Configuration and Amounts NRC Request I.B

1. Describe the Thermo-Lag 330-1 barriers installed in the plant to

a. meet 10 CFR 50.48 or Appendix R to 10 CFR Part 50

b. support an exemption from Appendix R,

c. achieve physical independence of electrical systems,

d. meet a condition of the plant operating license,

e. satisfy licensing commitments.

The descriptions should include the following information: the intended purpose and fire rating of the barrier, and the type and dimension of the barrier.

2. For the total population of Thermo-Lag fire barriers described under Item I.B.1, submit an approximation of:

a. For cable tray barriers: the total linear feet and square feet of 1-hour barriers and the total linear feet and square feet of 3-hour barriers.

b. For conduit barriers: the total linear feet of 1-hour barriers and the total linear feet of 3-hour barriers.

c. For all other fire barriers: the total square feet of 1-hour barriers and the total square feet of 3-hour barriers.

d. For all other barriers and radiant heat shields: the total linear or square feet of 1-hour barriers and the total linear or square feet of 3-hour barriers, as appropriate for the barrier configuration or type.

FPC Response to I.B.1 and I.B.2 Several exemptions from Appendix R used the protection of associated safe shutdown circuits with Thermo-Lag fire barrier material as part of the justification.

Thermo-Lag fire barriers were used specifically for additional protection for two exemptions.

In one exemption as a method to eliminate intervening combustibles, and to protect a safe shutdown valve located near an opposite train pump.

In the other to protect one train of redundant circuits in the vicinity of a stairwell to justify fire area separation by other than a three hour barrier.

Information was submitted to the NRC on the configurations of Thermo-Lag 330-1 on July 29, 1992, October 2, 1992, and April 15, 1993, in response to NRC Bulletin 92-01, " Failure of Thermo-Lag 330 Fire Barrier System to Maintain Cabling in Wide Cable Trays and Small Conduits Free from Fire Damage," and its Supplement.

A summary of Thermo-Lag configurations identifying the types, purposes, sizes, ratings, and amounts of material is 1

provided below.

L U. S. Nuclear Regulatory Commission 3F0195-03 Page 7 of 17 i

11EE PURPOSE SilE FIRE RATING AMOUNT

• Conduit (1) 1/2" 1 Hour 24 ft.

Conduit (1) 3/4" 1 Hour 320 ft.

Conduit (1) 3/4" 3 Hour 70 ft.

Conduit (1) 1" 1 Hour 185 ft.

Conduit (1) 1" 3 Hour 181 ft.

Conduit (1) 1 1/4" 1 Hour 40 ft.

Conduit (1) 1 1/2" 1 Hour 779 ft.

Conduit (1) 1 1/2" 3 Hour 378 ft.

t Conduit (1) 2" 1 Hour 701 ft.

Conduit (1) 2" 3 Hour 58 ft.

Conduit (1) 3" 1 Hour 1107 ft.

Conduit (1) 3" 3 Hour 1552 ft.

Conduit (1) 4" 1 Hour 104 ft.

Conduit (1) 5" 1 Hour 80 ft.

Conduit (1) 5" 3 Hour 36 ft.

z Cable Tray (1) 4"X 4" 1 Hour 144 ft./ 192 ft Cable Tray (1) 6"X 4" 3 Hour 51 ft./ 85 ft.j Cable Tray (1) 6"X 6" 1 Hour 9 ft./ 18 ft.2 Cable Tray (1) 6"X 6" 3 Hour 206 ft./ 412 ft.2 Cable Tray (1) 12"X 4" 1 Hour 178 ft./ 475 ft.2 Cable Tray (1) 12"X 4" 3 Hour 40 ft./ 107 ft.2 Cable Tray (1) 12"X 6" 1 Hour 72 ft./ 216 ft.2 Cable Tray (1) 12"X 6" 3 Hour 122 ft./ 366 ft.2 Cable Tray (1) 18"X 6" 1 Hour 144 ft./ 576 ft.2 Cable Tray (1) 18"X 6" 3 Hour 72 ft./.288 ft.2 2

Cable Tray (1) 24"X 4" 1 Hour.

290 ft./1351 ft.2 Cable Tray (1) 24"X 4" 3 Hour 24 ft./ 112 ft.

Cable Tray (1) 24"X 6" 1 Hour 637 ft./3185 ft.2 Cable Tray (1) 24"X 6" 3 Hour 126 ft./ 630 ft.2 Cable Tray (2) 24"X 6" 1 Hour 20 ft./ 100 ft.2 11EE PURPOSE SIZE FIRE RATING' AMOVNT' Junction Boxes (1)

Various 1 Hour 288 ft.2 (18)

Valve Box (2) 4'X 6'X 4' 1 Hour 96 ft.2 Valve Box (1) 4'X 5'X 3.5' 1 Hour 70 ft.2 Damper Box (1) 2.5'X 2.5'X 2' 3 Hour 17 ft.2 (one)

Purpose Codes:

(1) Appendix R (2) Appendix R Exemption

• The amounts of Thermo-Lag material provided above were estimated i

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i U. S. Nuclear Regulatory Commission

.3F0195-03 Page 8 of 17 IlP.E PURPOSE SRI

' FIRE RATING MOUNT

• Containment (1)

Various 1 Hour 68 ft.2 Penetrations i

Radiant Enerav Heat Shields in the Reactor Buildina Conduit (1) 3/4" 0.5 Hour 208 ft.

Conduit (1) 1" 0.5 Hour 152 ft.

Conduit (1) 1 1/2" 0.5 Hour 272 ft.

Conduit (1) 3" 0.5 Hour 48 ft.

Cable Tray (1) 24"X 6" 0.5 Hour 80 ft.

Containment (1)

Various 1 Hour 68 ft.2 Penetrations Purpose Codes:

(1) Appendix R (2) Appendix R Exemption b

Estimated Total Linear Feet of Thermo-Lag Covered Cable Tray 2135 ft.

b Estimated Total Linear Feet of Thermo-Lag Covered Conduit 5615 ft.

b Total 7750 ft.

The amounts of Thermo-Lag material provided above were estimated b

Does not include radiant energy heat shield amounts II. Important Barrier Parameters In a letter dated July 29, 1993, from NUMARC to the NRC, twenty-four (24) important fire barrier parameters and eight (8) parameters of importance for cables protected by fire barriers were identified.

NRC Request II.B

1. State whether or not you have obtained and verified each of the aforementioned parameters for each Thermo-Lag barrier installed in the plant. If not, d'scuss the parameters you have not obtained or verified.

Retain detailed information on site for NRC audit where the aforementioned parameters are known.

2. For any parameter that is not known or has not been verified, describe how you will evaluate the in-plant barrier for acceptability.

3. To evaluate NUMARC's application guidance, an understanding of the types and extent of the unknown parameters is needed.

Describe the type and extent of the unknown parameters at your plant in this context.

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l U. S. Nuclear Regulatory Commission 3F0195-03 Page 9 of 17 FPC Response to II.B.1 The following discussion pertains to the status of information regarding important barrier parameters identified in Section II.A of Reference D.

The information was obtained from plant documentation of original barrier construction and verified by recent walkdowns of barrier installations, except as noted below.

During our Spring 1994 refueling outage, some destructive examination of Thermo-Lag installations were performed from which additional installation details were obtained and verified.

Important Fire Barrier Parametern 1.

Raceway Orientation - This information has been obtained and verified for cable trays from a documentation review and walkdowns of all areas.

The results are documented on walkdown forms detailing protected circuits in each fire area.

Walkdown documentation and photographs verify externally observable characteristics.

2.

Conduit Orientation - Obtained and verified as above for raceway installations.

3.

Junction Boxes and Lateral Bends - Obtained and verified as above for raceway installations.

4.

Ladder-back Cable Tray with Single Layer Cable Fill - All trays outside of containment are aluminum ladder back tray.

Engineering records of as built configurations document the percentage of cable fill for each tray. This information has not been verified by field walkdown. 4160v and 6900v cable trays are laid in a single layer. Cables for 480v and below are not limited to single layer and are laid randomly.

5.

Cable Tray with T-section - The application of Thermo-Lag protection to cable trays with T-sections have been documented during plant wal kdowns.

Both horizontal and vertical T-sections have been protected, however some construction details have not been verified.

6.

Raceway Material - The cable tray and conduit material is aluminum for areas outside the Reactor Building. Inside the Reactor Building conduit material is a combination of black iron coated with Plasite and aluminum, and cable tray material is aluminum.

7.

Support Protection, Thermal Shorts - Intervening steel and support materials were protected for a distance of at least 18 inches, or for supports, to the point of attachment to the building. This applies to both one and three hour rated configurations.

8.

Air Drops - The protection of one air drop has been identifled from the documentation review.

It has not been verified that this is the only air drop.

9.

Baseline Fire Barrier Panel Thickness - All 1-hour Thermo-Lag installations are 5/8" -0,+1/8, and 3-hour installations are 1-1/4" -

0,+1/4.

This has been established by review of construction documentation, destructive examination, and examination of stock remaining from initial construction.

U. S. Nuclear Regulatory Commission 3F0195-03 Page 10 of 17

10. Preformed Conduit Panels - Preformed conduit sections were used and are documented,

11. Panel Rib Orientation - The construction documentation does not expressly identify the panel v-rib orientation.

Destructive examination of Thermo-Lag tray protection conducted to date has shown l

v-rib installation to be parallel to the raceway.

12. Unsupported. Spans - The maximum unsupported span of a horizontal Thermo-Lag panel configuration is approximately 40 inches.

This condition occurs where a 24" cable tray t-section exists. This maximum span has not been verified.

13. Stress Skin Orientation - Stress skin is located on the inside only for one hour rated configurations and on both the inside and outside for three hour rated configurations.

This has also been verified by the destructive examination conducted to date.

14. Stress Skin Over Joints - No joints were reinforced with stress skin.

15. Stress Skin Ties - Stress skin ties were not used.

16. Dry-fit, Post-buttered, or Pre-buttered Joints - All joints were pre-buttered and post-buttered.

This has been verified by documentation reviews and walkdowns.

17. Joint Gap Width - Joints were constructed with no allowed gap width as well as being pre-buttered.

18. Butt Joints or Grooved and Scored Joints - Butt joints, and score and fold joints were used at Crystal River Unit 3.

19. Steel Bands or Tie Wires - Stainless steel bands and tie wires were used in construction of the Thermo-Lag cable tray barriers and for bundled multiple conduit barriers. Stainless steel tie wires were used for construction of individually wrapped conduits.

20. Band / Wire Spacing - Steel band spacing is documented in the installation work packages as not to exceed 12 inches center to center.

Walkdowns have verified that approximately 95% of installations have band / wire spacing that does not exceed 6 inches.

21. Band / Wire Distance to Joints - Steel band spacing is documented in installation work packages as not to exceed 2 inches from the joint or edge of the Thermo-Lag configuration.

22. Internal Bands in Trays - No internal bands in trays have been identified, however this was an option available to installers during barrier construction.

23. Additional Trowel Material Over Sections and Joints - Additional trowel grade material was applied to Thermo-Lag barriers in many locations.

When evaluating specific barrier installations, credit will be taken for additional trowel grade material where it is actually applied.

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U. S. Nuclear Regulatory Commission 3F0195 Page 11 of 17

24. Edge Guards - No tray edge guards were used.

Parameters Imoortant to Cables Protected by Fire Barri-The parameters of importance (8 items) concerning cable.

'otected by fire barriers have been obtained and verified, except as notec below:

5.

Proximity of cables to the unexposed (inside) surfaces of the fire-barrier.

This parameter is known for medium voltage (4160v and 6900v) circuits.

These circuits are laid single layer in-trays.

For low voltage (480v -

and below) cables were laid randomly.

Although' fill percentage is -

known, the actual depth of the cable fill within trays could vary due to the random lay pattern.

t FPC Response to II.B.2 The response requested here assumes that use of the NEI Application Guide will be the principal method for determining barrier performance. Since a limited number of barrier configurations at CR-3 are bounded by the Guide, Florida Power Corporation will use the analytical tools developed by the EPRI Tailored Collaboration Project to determine barrier performance and circuit functionality limits. The analytical tools are still being refined, I

therefore the exact parameters of importance for these analyses have not been finalized.

It is expected that the final listing of important parameters will be bounded by the eight parameters requested here.

For any additional parameter that may be identified as unknown, the l

following actions are available to substantiate the acceptability of the in-plant configuration.

1.

Additional document searches along with plant walk downs where appropriate will be used to verify the important parameters in question for installed configurations.

t 2-Bounding assumptions concerning the important parameters relative to barrier installation will be made where it is conservative to do so and j

where qualification will support it.

I 3.

If aecessary, destructive examination will be performed on representative samples.

t FPC Response to II.B.3 Items 4 and 5 of the NRC parameter listing address issues relative to potential cable to barrier contact for cable trays. This is an unresolved l

issue at this time, and barrier inspection to ascertain this would be difficult or impossible. Barrier contact would be most likely to occur in i

situations of large cable fills.

However, the large cable fills also provide significant thermal mass that could improve barrier system performance and mitigate the effect of cables in contact with the barrier.

This issue becomes important when determining cable functional failure as distinct from determining fire barrier endurance.

U. S. Nuclear Regulab. Commission 3F0195-03 Page 12 of 17 Item 8 is an important parameter in determining the total period of fire exposure available to a protected circuit (the fire barrier and the enclosed cable) during which it will remain functional, Acceptance criteria for cable functionality limits have not yet been determined. However, since all safe shutdown cable at CR-3 is IEEE 383 fire resistance tested and rated, with thermoset jacket and insulation, it is clear tiiat circuits will remain functional well beyond the point at which the inside of a fire barrier reaches 250'F + ambient. Development of an acceptance criteria for rating plant specific cable performance is continuing within FPC, and as part of the TC Project.

Florida Power Corporation will conduct chemical tests of Thermo-Lag material to the extent necessary to determine that barrier material installed at CR-3 is equivalent to material that has been used in tests reported in the NEI Application Guide.

III.

Thermo-Lag Fire Barriers Outside the Scope of NUMARC Program NRC Request III.B

1. Describe the barriers discussed under Item I.B.1 that you have determined will not be bounded by the NUMARC test program.

2. Describe the plant-specific corrective action program or plan you expect to use to evaluate the fire barrier configurations particular to the plant.

This description should include a discussion of the evaluations and tests being considered to resolve the fire barrier issues identified in GL 92-08 and to demonstrate the adequacy of existing in-plant barriers.

3. If a plant-specific fire endurance test program is anticipated describe the following:

a.

Anticipated test specimens.

b.

Test methodology and acceptance criteria including cable functionality.

FPC Response to III.B.1 The evaluation of the Thermo-Lag fire barriers at CR-3 against the NEI Application Guide has determined that the majority of our installations are not bounded by currently tested configurations.

Fxamples of typical installations that differ from tested configurations include:

Multiple conduits of different sizes enclosed in a single barrier.

Some of these are in a square geometry and others are in a single

plane, i

Junction boxes of various sizes constructed of aluminum with multiple conduit penetrations.

Valve enclosure boxes attached to concrete floors and walls, and supported internally by steel angle.

U. S. Nuclear Regulatory Commission

-3F0195-03 Page 13 of 17 A fire damper enclosure which extends from a concrete floor upward a short distance to enclose the damper.

Containment penetration assemblies protected by cylin.trical enclosures attached to the vertical containment wall.

Radiant energy snicids installed within the containment.

Cable _ tray, t-section, and conduit enclosures of varying geometries constructed to also enclose nearby intervaning combustibles, and to enclose structural support members at both or thogonal and oblique angles.

(For compliance with the '18 inch rule.')

On the issue of cable tray and conduit enclosures constructed as above, Florida Power Corporation has submitted a specific request to the NEI Working Group to request guidance for addressing barrier segment interruptions and interfaces created by this type of construction. We are awaiting an answer to this request to determine the extent to which these configurations can be bounded by existing tests.

Florida Power Corporation has identified a number of additional barrier configurations that we would like to have included in future test programs.

NEI will in fact be conducting additional tests, however the specific configurations to be tested have not been identified.

It is anticipated that additional test results will bound some additional CR-3 configurations that are currently unbounded.

A schedule for additional testing has not been announced.

FPC Response to III.B.2 Florida Power Corporation will analyze all Thermo-Lag fire barriers using the methodology outlined in Attachment 1.

Since the FIVE methodology and the TC Fire Barrier Rating Tools will focus on fire barrier behavior, it is anticipated that many of the CR-3 unique configurations can be accurately rated for fire resistance, even though they may not be strictly bounded by configurations in the NEI Application Guide.

Once a fire resistance rating is established, the associated fire modelling and TC tools will be applied to determine credible fire exposure and circuit damage potential. Corrective actions will be developed as appropriate to each fire area utilizing the options noted in Section V.B, or others that may be developed in the future.

FPC Response to III.B.3 i

During the week of December 5-9, 1994 Florida Power Corporation conducted fire endurance tests of typical CR-3 fire barrier configurations.

The tests were conducted at Morestel, France in a test furnace owned by French fire barrier manufacturer Mecatiss.

The test was witnessed by Underwriters Lab, Babcock & Wilccx Nuclear Technologies, and FPC personnel. Plans for these tests were previously reported in Reference A.

Tests were performed on specimens protected by Thermo-Lag and specimens of Thermo-Lag with an overlay of Mecatiss blanket. Both one and three hour tests were conducted.

The same configurations were used for both tests.

4 They consisted of two individual 3/4" conduits with a 90' bends and a 90'

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'O. S. Nuclear Regulatory Commission 3F0195-03 Page 14 of 17 condulet installed in each run, and a group of six conduits gang wrapped together between upper and lower panels with preformed conduit wrap sections completing the envelope on the sides.

This was an ' upgraded' installation typical of construction at CR-3 with pre-buttered and post-buttered joints and with an overlay of trowel grade material. One of the I hour conduits was protected with Thermo-Lag that had been removed from an in-plant installation at CR-3.

The test methodology and acceptance criteria followed the guidance of NRC l

Generic Letter 86-10 Supplement 1.

Evaluation of the test results has not been completed therefore official test results are not available for publication.

Additional details of the test configuration and test results will be available for inspection onsite.

IV.

Ampacity Derating NRC Request IV.8

1. For the barriers described under Item I.B.1, describe those that you have determined will fall within the scope of the NUMARC program for ampacity derating, those that will not be bounded by the NUMARC program, and those for which ampacity derating does not apply.

2. For the barriers you have determined fall within the scope of the NUMARC program, describe what additional testing or evaluation you will need to perform to derive valid ampacity derating factors.

3. For the barrier configurations that you have determined will not be bounded by the NUMARC test program, describe your plan for evaluating whether or not the ampacity derating tests relied upon for the ampacity derating factors used for those electrical components protected by Thermo-Lag 330-1 (for protecting the safe-shutdown capability form fire or to achieve physical independence of electrical systems) are correct and applicable to the plant design.

Describe all corrective actions needed and submit the schedule for completing such actions.

4. In the event that the NUMARC fire barrier tests indicate the need to upgrade existing in-plant barriers or to replace existing Thermo-Lag barriers with another fire barrier system, describe the alternative actions you will take (and the schedule for performing those actions) to confirm that the ampacity derating factors were derived by valid tests and are applicable to the modified plant design.

FPC Response to IV.B Florida Power Corporation had intended to use %e results of ampacity testing done by other utilities to provide appropriate ampacity derating

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factors for power circuits enclosed in Thermo-Lag barriers. These tests were conducted according to various draft versions of IEEE P848,

" Procedure for the Determination of the Ampacity Derating of Fire Protected Cables." However the NRC staff has identified several concerns with this standard which have not been resolved.

Since the potential exists for tests performed to earlier versions of P848 to result in non-conservative derating factors, it would be premature to use these test results as the basis for ampacity derating of Thermo-Lag protected cables i

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U. S. Nuclear Regulatory Commission.

3F0195-03 Page 15 of 17 until technical issues relating to P848 are resolved. Therefore, we will respond to this portion of the information request when technical issues with respect to ampacity derating factors have been resolved.

V.

Alternatives i

NRC Request V.B Describe the specific alternatives available to you for achieving compliance with NRC fire protection requirements in plant areas that contain Thermo-Lag fire barriers.

Examples of possible alternatives to Thermo-Lag-based upgrades include the following:

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1. Upgrade existing in-plant barriers using other materials.

2. Replace Thermo-Lag barriers with other fire barrier materials or systems.

3. Reroute cables or relocate other protected components.

4. Qualify 3-hour barriers as 1-hour barriers and install detection and suppression systems to satisfy NRC fire protection requirements.

FPC Response to V.B Florida Power Corporation intends to maintain all options for resolution of the Thermo-Lag fire barrier issue open at this time.

Upgrades to the existing Thermo-Lag barriers may not be an available option for some of the configurations at CR-3.

The existing installation would not allow additional material to be added to these configurations due to hanger loading criteria, ampacity derating, and cost.

Other alternatives are being explored as listed below.

1. The re-evaluation of engineering analyses used for determining Appendix R safe shutdown pathways, equipment, and actions will provide a basis for reduction in the scope of protected circuits and their associated fire barriers. An initial review of this option indicates a reduction in the number of circuits requiring protection at CR-3 is probable.

2. Exemption requests will be submitted based upon the use of fire modeling in conjunction with fire endurance test results. These would demonstrate adequate protection by the installed fire barriers is available for the existing fire hazard.

Florida Power Corporation is presently involved in detailed modeling of plant area fire hazards using the EPRI FIVE methodology and the EPRI TC Project in order to provide an assessment of the Thermo-Lag fire barriers. This approach is likely to be the mainstay of FPC's resolution of this issue.

3. Rerouting cables or relocating components as a means of protecting safe shutdown functions is considered to be a possible alternative. For CR-3, this option is very expensive and is not seen as a viable alternative to significantly uduce the amount of Thermo-Lag material used in the plant.

4. The qualification of three hour barriers as one hour barriers with the installation of detection and suppression systems is a possible option.

This option is also expensive and would involve an extensive amount of evaluation and plant modification to accomplish.

There may be some i

d. S. Nuclear Regulatory Commission 3F0195-03

~Page 16 of 17 limited application of this option at CR-3, however the serious negative impact to overall plant safety and reliability from the i

potential for spurious suppression actuation will be very carefully reviewed when considering application of this option.

5. Upgrading of existing barriers by the application of other fire barrier materials to segments of Thermo-Lag barriers that do not provide the.

required protection is a possible alternative.

As stated above, Florfda Power Corporation will use any or all options to.

resolve the Thermo-Lag issue.

The choice of option used will depend i

primarily on the viability of the option and the associated cost. Which option is chosen for a specific application will be determined once all of the information on the installed configurations and associated test data is analyzed, and an engineering evaluation is performed to determine benefit / cost.

VI.

Schedules NRC Request VI.B Submit an integrated schedule that addresses the overall cm rective action schedule for the plant.

At a minimum, the schedule should address the following aspects for the plant.

1. implementation and completion of corrective actions and fire barrier upgrades for fire barrier configurations within the scope of the NUMARC

program,

2. implementation and completion of plant-specific analyses, testing, or alternative actions for fire barriers outside the scope of the NUMARC program.

FPC Response to VI.B.1 The following information provides the schedule for resolution of the Thermo-Lag fire barrier material issue associated with configurations bounded by the scope of the NEI program.

1. Florida Power Corporation will have determined and documented those Thermo-Lag fire barrier configurations which are bounded by the NEI program and Ate acceptable as is by May 31, 1995.

2. Those Thermo-Lag fire barrier configurations which are bounded by the NR; ARC program but da ng1 meet the required fire endurance criteria will be evaluated in accordance with the alternatives above and an action plan for resolution of the unqualified barriers developed and submitted to the NRC by December 31, 1995.

a c.

U. S. Nuclear Regulatory Commission 3F0195-03 Page 17_ of 17 FPC Response to VI.B.2 The following information provides the schedule for resolution of the Thermo-Lag fire barrier material issues associated with configuration outside the scope of the NEI program.

1. The damper box identified in III.B.1 as not bounded by the NEI program will be upgraded to fully meet the 10 CFR 50. Appendix R criteria by September 30, 1995. Present plans are to utilize other qualified fire barrier materials to upgrade this barrier.

2. The configurations represented by the junction boxes (18), valve boxes (2), and other unique configurations identified in III.B.1 may be included in the NEI expanded test program.

If this is the case, an action plan to resolve the qualification of these barriers will be submitted to the NRC within 90 days of the receipt of the test reports on these barriers. This action plan will follow the guidance provided in Attachment 1.

If these configurations are not incorporated into future tests, then the actions of item 3 below will be followed.

3. For configurations not included in the test program, barrier effectiveness and fire modelling will be used-to assess the circuit or equipment protection provided.

Action plans for resolution of the compliance of those barriers will be submitted by December 31, 1995.

4. The radiant energy heat shields and the containment penetration barriers will be evaluated against the provisions of Attachment 2 and an action plan on the resolution of the qualification of these barriers submitted to the NRC by October 31, 1995.

VII.

Sources and Correctness of Information NRC Request VII.B Describe the sources of the information provided in response to this request for information (for example, from plant drawings, quality assurance documentation, walk downs or inspections) and how the accuracy and validity of the information was verified.

FPC Response to Vll.B The sources of information provided in this letter include quality document record searches, plant walk downs, and reviews of plant drawings.

The configurations and estimated amounts of materials involved (item I) were obtained through quality record searches and walk downs.

The important barrier parameters (Item II) were determined through quality document searches.

The accuracy and validity ~of this information was verified through walk downs and reliance on the quality record system at CR-3.

Some destructive examinations were performed as part of modifications which affected Thermo-Lag wrapped cable trays.

This information is being retained on site and is available for NRC audit.-

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