ML18057A372

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Forwards Addl Info Re Util Request for Exemption from Separation Criteria of 10CFR50,App R,Section III.G.2 Re Containment Air Room
ML18057A372
Person / Time
Site: Palisades Entergy icon.png
Issue date: 08/08/1990
From: Slade G
CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9008140008
Download: ML18057A372 (22)
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1 . .... consumers Power POW ERi Nii PROliRESS Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 August 8, 1990 Nucl.ear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 -LICENSE DPR-20 -PALISADES PLANT -CONTAINMENT AIR ROOM -10CFR50 APPENDIX R EXEMPTION REQUEST -ADDITIONAL INFORMATION GB Slade General Manager Consumers Power Company (CPC) letter dated October 4, 1985, requested an exemption from the separation criteria of 10CFR50 Appendix R, Section III.G.2 for the pressure and level transmitters in the Containment Air Room. Subsequently, after discussion with the NRC staff, our January 11, 1989 letter proposed Appendix R compliance for the Containment Air Room using post-fire safe shutdown methodology similar to that methodology which could be used after a Main Steam Line Break (MSLB) inside containment.

If used as an Appendix R compliance strategy, this methodology could require exemptions from two other Appendix R criteria (III.G.3 & III.L.2).

After further study, the NRC staff determined that neither the October 4, 1985 nor the January 11, 1989 Exemption Request contained enough substantiation to allow an exemption.

CPC then decided to install fixed suppression to bring the area into compliance with Section III.G.2 and committed to install the suppression system during the 1990 Refueling Outage. Because of potential containment sump level problems caused by the suppression system actuating during postulated transients, intricate shutoff controls of the fire water made the installation more expensive than previously estimated.

Therefore, after extensive discussion with the NRC staff, it was mutually decided that if CPC would further analyze the effect of a fire using state-of-the-art methods and would still conclude that a credible worst case fire could not prevent post-fire safe shutdown, the staff would re-evaluate CPC's October 4, 1985 exemption request. Also, it was agreed that the planned installation of a fixed suppression system could wait until the exemption request re-evaluation is complete.

Thus, if installation is still required, it will be delayed until a shutdown of sufficient length after the 1990 Refueling Outage. Attachment 1, analysis EA-GWS-90-002, is CPC's state-of-the-art re-analysis of the effect of a Containment Air Room fire. The analysis uses the Hazard I Fire Assessment Method which is approved by the National Institute of Standards and Technology, assumes very conservative amounts of combustibles

Regulatory Commission Palisades Plant lOCFRSO Exemption Req -Add Info Draft and rate of combustion, and concludes that a credible worst case fire in the Containment Air Room would leave sufficient instruments operable to safely shutdown the plant. In view of the above additional information, CPC again requests that the Containment Air Room be exempted from the separation criteria of lOCFRSO Appendix R,Section III.G.2. This request is made under the provisions of lOCFRS0.12 (a)(2)(ii) in that application of the requirements of Appendix R,Section III.G.2 in these particular circumstances is not necessary to achieve the underlying purpose of the rule. OS< --\L::s Gerald B Slade General Manager Palisades Nuclear Plant CC: Administrator

-Region III NRC resident Inspector

-Palisades OC0790-0060-NL04 2

OC0790-0060-NL04 ATTACHMENT 1 Consumers Power Company Palisades Plant Docket 50-255 ANALYSIS OF THE EFFECT OF A FIRE ON SAFETY RELATED INSTRUMENTS IN THE CONTAINMENT AIR ROOM August 8, 1990 19 Pages

., .. @).CONSUMERS

-POWER Palisades Nuclear Plant Engineering Analysis Work Sheet GWS-90-002 l'OUIERIN6 MICHl6RN'S l'R06RESS Sheet __ 1 __ of _ __._19..___

Title Analysis of the effect of a fire on safety related instruments in the Containment Air Room. INITIATION AND REVIEW Rev Initiated Initiator Review Method Check ( II' ) Technically Reviewed Reviewer # Appd Alt Det Qual Appd Description By .\ Date By Cale Rvw Test By Date Bx ,,,..., 0 Original Issue GWSle'eP0r 8/6/90

/ ;;,u. )<j. IZ./ /J-7-?CI V' Reference/Comment OBJECTIVE The purpose of this analysis is to show the impact a fire in the Containment Air Room would have on safety related instruments located in that room. This analysis will show that the affect on the instruments will be small enough such that sufficient instruments will be available to safely shut down the plant. ANALYSIS INPUT 1. Hazard I Rre Assessment Method, Version 1.0 National Institute of Standards and Technology, May 1989. 2. Various plant drawings showing room layout, equipment locations, conduit, cable and tubing routings.

3. SFPE Handbook of Rre Protection Engineering, Copyright 1988, Page 2-14. 4. NUREG/CR-5384, SAND89-1359, A Summary of Nuclear Power Plant Fire Safety Research at Sandia National Laboratories, 1975-1987.
5. EPRI NP-1881, Categorization of Cable Flammability Intermediate-Scale Fire Tests of Cable Tray Installations.
6. Generic Letter86-10, Implementation of Fire Protection Requirements, April 24, 1986 7. Licensing correspondence pertaining to ttie Containment Air Room. 8. Development and Results of a Test Program to Demonstrate Compliance with IEEE Std. 384 and R.G. 1.75 Electrical Separation Requirements, IEEE Power Engineering Review, June 1987.

' cti>> CONSUMERS . POWER POIDERIN6 Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET Sheet Rev# M

O::"'"Af:'C:C:

ASSUMPTIONS

1. A cable tray fire is the only type of fire that needs to be considered for the following reasons:
  • Access to this area is severely limited during operations.

Personnel entering containment dress and undress outside of containment.

There are no "step-off" pads and no discarded Anti-Cs inside of containment during operation.

Everything is stored or discarded outside of containment when the plant is operating.

  • Strict administrative controls dictate that all loose material be removed from containment prior to startup to prevent containment sump plugging and transient fires. Since controls are in place to remove the risk of transient fires during operation and the only major fixed combustible is cable, a cable tray fire is the only fire that needs to be considered.
2. Fires that occur during plant operations are considered worst case since that is the time the instruments would be needed to safely shut down. 3. A worst case fire involves the cables in one channel of cable trays only. By the use of cable tray fire stops and other protective features and controls, it can be assumed that one train of instrumentation circuits will be free of fire damage for anticipated fires inside containment.

This has been agreed to by the NRC Staff and documented in our exemption request dated 7/23/85. 4. Narrow range (0-100%) Steam Generator level indication is sufficient for safe shutdown.

This is acceptable because a LOCA or MSLB is not considered to be occurring at the same time as a fire. 5. Level indication in one steam generator is sufficient for safe shutdown.

Again because a LOCA or MSLB is not occurring simultaneously.

ANALYSIS This analysis for a fire in the Containment Air Room is organized as follows: 1. Description of Room 2. Likelihood of a fire. 3. Type of a fire. 4. Consequences of a fire. GWS-90-002 2 of __ 19 __ 0 Reference/Comment

.. @)CONSUMERS

  • POWER POIDERIN6 Descrjptjon of Room Palisades Nuclear Plant ANAL VSIS CONTINUATION SHEET Sheet Rev# The room is oddly shaped with a 13 1/2 foot high ceiling. Total volume is approximately 14,420 cubic feet. The walls, floors and ceiling are constructed of poured, reinforced concrete.

The northeast corner contains a metal staircase.

The stairs go up only. The area is well ventilated.

Air flow is out of the room. The cable trays in the room are lightly loaded. The majority of the cable trays located near the instruments contain small gauge instrumentation cables. Table 1 has a listing of the cable trays in this room along with their loading obtained from the circuit and raceway schedule.

Figure 1 shows a 3-D perspective of the room with approximate locations of the raceways.

The flow of air in the room is from the louver at the 590' elevation up the stairwell and through the door on the 607' elevation.

Figure 2 with views A through F is a plan view of the room with the approximate locations of the various instrumerits in this room. Table 1 RACEWAY CABLE SIZE Cinches) LENGTH %Fill CABLE VOL IME CcufO GAUGE HEIGHT WIDTH (Feet) Ria ht Left CP226 (R) AWG14 4.00 6.00 25.00 18.10% 0.75 CV226 (R) AWG16 4.00 6.00 25.00 6.10% 0.25 CP216 (L) AWG12-14 4.00 6.00 40.00 11.90% 0.79 CV216 (L) AWG16 4.00 6.00 40.00 11.10% 0.74 CV224 (R) AWG16 4.00 6.00 25.00 10.30% 0.43 CP224 (R) AWG12-14 4.00 6.00 25.00 17.10% 0.71 4CP224 (R) AWG14 4.00 6.00 22.00 2.30% 0.08 4CV224 (R) AWG16 4.00 6.00 22.00 3.70% 0.14 CP214 (L) AWG12-14 4.00 6.00 20.00 11.90% 0.40 CV214 (L) AWG14-16 4.00 6.00 20.00 18.50% 0.62 CP212 (L) AWG12-14 4.00 6.00 20.00 11.90% 0.40 CV212 (L) AWG14-16 4.00 6.00 20.00 22.10% 0.74 CP222 (R) AWG12-14 4.00 6.00 20.00 17.10% 0.57 CV222 (R) AWG16 4.00 6.00 20.00 16.00% 0.53 4CP222 (R) AWG14 4.00 6.00 16.00 2.30% 0.06 4CV222 (R) AWG16 4.00 6.00 16.00 9.20% 0.25 3CP212 (L) AWG12-14 4.00 6.00 14.00 1.20% 0.03 3CV212 (L) AWG14 4.00 6.00 14.00 14.40% 0.34 CP202 AWG2-14 4.00 12.00 25.00 18.20% 1.52 1.52 CP204 AWG2-14 4.00 12.00 23.00 16.70% 1.28 1.28 4CV180 (R) AWG16 4.00 6.00 10.00 0.50% 0.01 CV180 (R) AWG16 4.00 6.00 6.00 5.90% 0.06 CV170 (R) AWG16 4.00 12.00 12.00 3.00% 0.12 4CP210 (R) AWG14 4.00 6.00 6.00 1.70% 0.02 4CV210 (R) AWG16 4.00 6.00 6.00 9.30% 0.09 CP210 (R) AWG1/0-14 4.00 16.00 5.00 25.00% 0.56 CV210 (R) AWG16 4.00 16.00 5.00 8.60% 0.19 3CP214 (L) AWG14 4.00 6.00 17.00 1.20% 0.03 3CV214 (L) AWG16 4.00 6.00 17.00 13.10% 0.37 Total volume 1n cub1c feet= 7.62 7.25 -GWS-90-002 I 3 of 19 0 Reference/Comment Reference 7

.. @>> CONSUMERS

  • POWER
  • POIDERIN6 590' Figure 1 Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET PALISADES NUCLEAR PLANT CONTAINMENT AIR ROOM CABLE TRAYS OPENING TO THE REST OF CONTAIN MEN CP212 QY.....---...

c 603'-6" EA-GWS-90-002 Sheet 4 of _1_9 __ Rev# ___

Reference/Comment Reference 4 AIR INTAKE TO ROOM

. . *o CONSUMERS

  • POWER *. POUIERIN6
  • Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET PALISADES NUCLEAR PLANT 'f::2_ CONTAINMENT AIR ROOM Ill( MCC No. 15 MCC No. 16 II 19*-o* Transformer No. 15 Transformer No. 16 EA-GWS-90-002 Sheet 5 of _...:....:19=----

Rev # ___ ....:;.o __ _ Reference/Comment

..... _1*-*=-6' Reference 4 43'-, * : * ...... ;. '1 . . -.. * ...... ; .. ,

42'-0" Figure 2

.. 'G CONSUMERS

  • POWER --l'OUJERIN6 Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET EA-GWS-90-002 Sheet 6 of __:.1.=...9--Rev I PT-101A Reference/Comment EL. 604' Figure 2 (Contd) PT\ 7751C 8 8 8 '8 8 T-0751 C LT lo2 EL. 601' PTi7528 riT-7520 LT --07,A L T--OJ52C
  • 8 8 8 8 . I . Reference 4

© PT-0751 .,.,.

PT-0704 EL. 590' LT-0700 EL. 600* ELEVATED -----------E-PLATFORM EL. 600' ----:3--

/ PT-0105A PT-01058 EL. 590' EL. 590' II D Right channel Left Channel

.. EA-GWS-90-002

({>)CONSUMERS

  • POWER , l'OIDERIN6 Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET Sheet 7 of _ _.1 .... 9 __ Rev# ____ o ___ _ . --... -.... :-.. .:: .. . .... -8 I 8 I I ---I -=-CABLE TRAYS 8 8 8 I I 8 8 I I F Figure 2 (Contd) 8 8 8 8 8 8 8 EL. 603' 6" I I I II I I a a EL. 590' Table 2 shows the approximate horizontal distances between right and left channel transmitters in feet. The following observations can be made from this information:
1. Redundant steam generator pressure transmitters are.27 ft apart (PT-0751A/PT-0752D).
2. Redundant narrow range steam generator level transmitters are 16 ft apart for SG-A, (LT-0751A/LT-0751 D) and 7 ft apart for SG-8 (LT-0752A/LT-0752D).
3. Redundant wide range steam generator level transmitters are within one ft of each other. This does not prevent safe shutdown since the operator can modulate the Auxiliary Feedwater flow and keep the SG level within the narrow range. The wide range level transmitters are a minimum of 9 ft from their redundant narrow range instruments (LT-0757A/LT-0751 D, L T-0758A/LT-0752D, LT-07578/LT-0751A, L T-07588/L T-0752C).
4. Wide range pressurizer level transmitters are 1 O ft apart (L T-0102/L T-0103). 5. Although redundant wide range pressurizer pressure transmitters (PT-0105A/PT-01058) are located adjacent to each other, they are separated from redundant narrow range pressure transmitters by 12 ft (PT-0105A/PT-01018) and 12 ft (PT-01058/PT-0101A).

If both wide range pressurizer pressure transmitters were rendered inoperable, one of the narrow range pressure transmitters could be calibrated over the wide range before the approach to cold shutdown is made. Since cable trays are the only combustible in the room, and assuming one train of cables is the source of the fire, , the relative position of right and left channel redundant instruments to each other is not as important as their position relative to the hot gases which could be generated if one train of cables burned. Reference/Comment Reference 4 IL. 599' 7" EL. 598' 5"

. . . G. , CONSUMERS POWER POIUERIN6 Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET EA-GWS-90-002 Sheet 8 of _1_9 __ Rev# ____ o ___ _ Right Channel Instruments Steam generator Pressure Table 2 Q) > (I) ....I ..... LT-0752A 10 9 0 iii LT-0752C 10 9 ..... (I) c: 25 .5 (I) LT-0757A 9 10 27 (.!) E LT-0758A 6 7 23 25 Cl! (I) LT-0701 14 15 25 27 Ci5 LT-0702 en ...... c Q) ::I (/) E (/) ::J .._ a.. ...... ..... en 0 c iii ..... Q) (I) c: c (I) c Cl cu E ..c Cl! () (I) U5 ;i: Q) ....I ::I (/) (/) a.. ..... (I) N *;:: PT-0105A ::I (/) PT-0101A (/) (I) ..... a.. Q) > (I) ....I ..... (I) N *;:: ::I (/) (/) a.. LikelibQQd Qf 8 Ei(e One aspect of this issue is the likelihood of a fire. During plant operation external sources of ignition are extremely unlikely.

This leaves the possibility of a self initiated cable tray fire. As a result of fire research it has been found that for #12 AWG cables currents of from 120 to 130 amperes were required to induce open flaming. In full-scale testing, the intense period of fire activity persisted for between 40 and 240 seconds after which rapid reduction to self-extinguishment of the fire was observed.

In no case involving electrically initiated fires in rated low flame spread cables was propagation of the fire beyond the tray of fire origin observed.

Reference/Comment Pressurizer Level Reference 4

.. e e Palisades Nuclear Plant EA-GWS-90-002

' 'fp)coNSUMERS POWER ANAL YSIS CONTINUATION SHEET Sheet __ 9_ of

-POUIERIN6 PRacar:rr Rev# O In other tests conducted, locked rotor amperes (LRA) were applied to test cables to judge their impact on target cables. One of the design criteria for the test program was that the worst-case electrically induced fault would be on a motor feeder circuit, because the majority of large loads, and the more potentially damaging ones, are motor loads. The most credible worst-case fault would be the sustained application of locked rotor amperes (LRA) to the test cables. This type of fault was selected because it is a typical condition, it can be postulated as having an extended duration, and its magnitude is large enough to cause damage to the fault cable and adjacent cables. To select the test cable, typical plant cable feeder sizes were tabulated along with the corresponding maximum LRA for each feeder, and the corresponding motor pigtail conductor size. Based on preliminary screening test data, a relationship was developed between LRA durations and fusing (open circuit) of the motor pigtail conductors.

Using this relationship in conjunction with data obtained from the screening tests, the worst-case fault cable was selected, and was used in the subsequent configuration tests. The selected worst-case cable was the cable with the highest temperature at the time its corresponding motor pigtails fused (open circuited).

The tests demonstrated that when ignition occurred, the fire never propagated to an adjacent target cable even when both were touching.

The fires that occurred were self-extinguishing when the electrical fault was interrupted.

The amount of smoke created by the overload was extremely dense and would be readily detected by the plant fire detection systems. The majority of the cable trays in the vicinity of the instruments contain only instrumentation cable which is fused to prevent the high currents necessary to ignite the cable. Should the fusing still allow high currents it is unlikely that surrounding cables or cable trays would be affected.

Also the smoke generated would activate the detectors very early into a problem. Type Of A Eire From the previous section it can be seen that the most likely type of fire would be a small extinguishing fire that would generate a lot of smoke. For the purposes of analysis, we will assume a much worse fire the type of which would be most likely initiated by an external source. The type of fire was determined using an equation developed by B.T. Lee in a study conducted in 1985. This research indicates that the peak full scale heat release rate(q) can be predicted according to bench scale heat release measurements

'fs . . " 'rs = 0.45

  • qbs
  • A where the bench scale heat release value is the peak measured under irradiance conditions of 60 kW/sq m, and A is the exposed tray area actively pyrolyzing.

The active pyrolysis area, in turn, is estimated based on the type of cable and its bench scale heat release rate which can be obtained from Figure 2-1 .18 of the SEPE Handbook of Eire Protection Engineering, which gives dA/dt as a function of a " . Thus, at any given time t, . A 'bs dA A(t) = o + cit

  • t Using a conservative number 400kW/sq m for the bench scale heat release rate (322 is the mean for the ones listed) and 1.0sq rn/min. rate of flame coverage (obtained from Ref. 3 Figure 2-1.18). The fire shown in Table 3 was generated:

Reference/Comment Reference 8 Reference 3

.. *o CONSUMERS Palisades Nuclear Plant ANAL VSIS CONTINUATION SHEET EA-GWS-90-002

  • POWER Sheet 1 O of __ 1_9 __ . POUIERIN6 Rev# ____ o ___ _ Table3 0.00 0.00 0.0000 0.0000 30.00 0.25 1.5000 3.8333 64.10 60.00 0.63 3.8066 9.2155 154.10 90.00 1.02 6.1133 14.5976 244.10 120.00 1.40 8.4199 19.9797 334.10 150.00 1.79 10.7265 25.3619 424.10 180.00 2.17 13.0331 30.7440 514.10 210.00 2.56 15.3398 36.1261 604.10 240.00 2.94 17.6464 41.5082 694.10 270.00 3.33 19.9530 46.8904 784.10 300.00 3.71 22.2597 52.2725 874.10 330.00 4.09 24.5663 57.6546 964.10 360.00 4.48 26.8729 63.0368 1,054.10 390.00 4.86 29.1795 68.4189 1,144.10 420.00 5.25 31.4862 73.8010 1,234.10 450.00 5.63 33.7928 79.1832 l,324.10 480.00 6.02 36.0994 84.5653 1,414.10 510.00 6.40 38.4060 89.9474 1,504.10 540.00 6.79 40.7127 95.3296 1,594.10 600.00 7.55 45.3259 106.0938 1,774.10 630.00 7.94 47.6326 111.4760 1,864.10 660.00 8.32 49.9392 116.8581 1,954.10 780.00 9.86 59.1657 138.3866 2,314.10 900.00 11.40 68.3922 159.9151 2,674.10 1,080.00 0.00 0.0000 0.0000 0.00 This represents over 68 feet of 12 " wide cable tray with 50% fill involved in a fire. The volume at the end of the fire exceeds the total volume of either right or left channel cable trays in the Containment Air Room. This is considered a worst case fire. A slower burning fire is more likely however a slower fire would not produce as high a temperature as a faster fire. Conseguences of a Fjre Now that we have looked at the room configuration and at what we consider is a worst case fire, we can try to assess the impact this fire will have on instruments the operators need to safely shut down the plant. What we expect will happen is that hot air from the fire will travel along the ceiling and go up the stairway without having a negative impact on necessary instruments.

To verify this we will use fire modeling program called Hazard I developed by the National Institute of Standards and Technology.

Reference/Comment

. ' EA* GWS-90-002 ' .

POWER Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET Sheet 11 of __ POWERING Rev # ____ o ___ _ The first step in using Hazard I to validate our theory of what happens for a fire in the Containment Air Room is to input the necessary parameters into the program. We will do this in two parts. First we will look at the main part of the Containment Air Room, then we will look at the stairway.

Each area will be modeled separately.

The first parameter we input is the physical dimensions of the main part of the room. Figure 3 below shows what this room looks like to the computer.

Vent 1 represents the stairway going up. -Next we input the fire shown in table 2. Both the Heat Release Rate and the Area of the fire are input into Hazard I. Figure 3 The fire is located in the center of the room at a height of 9.8 feet. The ceiling floors and walls are all 6" thick concrete.

Ambient conditions:

Internal=

100 degrees F External = 120 degrees F 13' -6" Reference/Comment GWS-90-002

'* c:f J CONSUMERS POWER Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET Sheet _1_2_ of __ 19 __ POWERIN6 Rev# O The results of running this fire model are shown in graphs 1 through 4. As can be seen from these graphs, there is a layer of extremely hot air near the ceiling, that .extends down two feet during the worst part of the fire.

  • The lower layer of air in the room is significantly cooler than the upper layer. In addition, the wall temperature (which is where most of the instruments are mounted is also significantly cooler than the upper layer air temperature.

HEAT RELEASE -2000 ..........

Q) (/J ca Q) Q) a: 1000 +-' ro Q) I Reference/Comment 0 0. 0 1000.0 2000.0 3000.0 400 .0 400 -0 300 ..........

(].) i.... :::::J co i.... Q) 200 a. E Q) I-100 0 0.0

  • N = 1 Graph 1 Time (s) UPPER LA YER TEMPERATURES U Air Temp. 1 U Wall Temp. . . . , ... . . . .. .. . . . . .. .......................

-.. 1000.0 2000.0 3000.0 4000 0 N = 1 Graph 2 Time (s) e e Palisades Nuclear Plant ANAL VSIS CONTINUATION SHEET EA-Sheet GWS-90-002 13 of _19 __ ' G. CONSUMERS POWER . POUJERIN6 Rev# ___ o:__ __ -(.) -(]) .... :::J ca .... (]) a. E Q) 60.0 55.0 50.0 45.0 40.0 LOWER LAYER TEMPERATURES

.. . . . ... . . . . . . .. . . . . 1 L Air Temp. 1 L Wall Temp.

-E --.c .Q> (]) -: 603' Q) >. ctS _J 601'-6" 0.0 1000.0 2000.0 3000.0 4000.0 N = 1 Graph 3 Time (s) . LA YER HEIGHT 1 u Ceilin El. 603'-6" 600' 0.0 1000.0 N = 1 2000.0 Time (s) Graph 4 3000.0 4000.0 Reference/Comment

' ' '* G CONSUMERS

  • POWER /POWERING Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET EA-GWS-90-002 Sheet 14 of __ 19 __ Rev# ____ o ___ _ Now that we have modeled the main part of the room, we can model the stairwell area. Again, we input the physical dimensions of the stairway.

Figure 4 below shows what the stairway looks like to the computer.

Vent 1 represents the opening to the main part of the room. Vent 2 represents the opening to the rest of containment.

Next we input the fire shown in table 2. Even though the fire will be in the main section of the room we will assume it is all contained in the stairway.

Again, both the Heat Release Rate and the Area of the fire are input into Hazard I. The other inputs to Hazard I were the same as the previous model. I I I I I I I I I I I I The fire is located against a wall at a height of 9.8 feet. I 34' . )-------------,,-

l '/-I 20' 10' Figure 4 VENT2 6.5' The results of running this fire model are shown in graphs 5 through 8. As can be seen from these graphs, the layer of hot air, extends down to above elevation 607'. The lower layer of air in the stairwell is significantly cooler than the upper layer. In addition, the wall temperature (which is where the instruments are mounted is also significantly cooler than the upper layer air temperature).

Reference/Comment

    • 't '@>)CONSUMERS POWER POUIER/N6 Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET HEAT RELEASE EA-GWS-90-002 Sheet 1 5 of __ 19_ Rev# 0 Reference/Comment 3000..-------

1--u--.-----------.-----------..-----------.

2000 1000 0 0.0 1000.0 2000.0 3000.0 4000.0 N = 1 Time (s) Graph 5 UPPER LA YER TEMPERATURES 500 1 U AirTemp. 1 U Wall Temp. 400 -() -Q) '-300 :J ....... Cl> a. E 200 Cl> I-100 ...... .. . .. . . . . . .. . .. .. .. . . .. 0 0.0 1000.0 2000.0 3000.0 4000. N = 1 Time (s)

  • Graph 6
  • POWER POWERING -(.) 50.0 -Cl) L.. :::::J '-45.0 E Cl) I-40.0 Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET LOWER LAYER TEMPERATURES

.. 1 L Air Temp. . . ... . . . . . . . EA-GWS-90-002 Sheet 16 of __ 19_ Rev# 0-Reference/Comment . . . . ..... 1 L Wall Temp. 35.0

___ ___. 623' -E ::-619'-6" ..c 0) Cl) 616' Q) _J612'-6" 609' 0.0 -1000.0 2000.0 3000.0 4000.0 N = 1 Graph 7 Time (s) LA YER HEIGHT 1 u Ceilin El. 624' 1 000.0 2000.0 3000.0 4000.0 N = 1 Time (s) Graph 8

' ' " ,.C!f>JcoNSUMERS POWER

  • POUJERIN6 MIC:Hl6RN'S L*'-' Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET EA-GWS-90-002 Sheet 17 of _ _,_19,..__

Rev# 0 Now that we have a good idea what the temperatures will be at what elevations in the Containment Air Room and stairwell, we can see how many instruments will be affected.

In the main part of the room, equipment below elevation 601' 4" will be in the cooler part of the room. In the stairway, equipment below elevation 607' will be in the cooler part of the room. The safety related instruments in the Containment Air Room were looked at to see if enough instruments would be available to safely shut down the plant. In looking at the instruments, not only was the instrument elevation looked at but so was the elevation of the process tubing and cable. Table 4 was developed to show the results of this evaluation.

It should be noted that emergency operating procedure EOP 9.0 informs the operator that during degraded containment conditions, the operator should not rely on any single instrµment indication due to instrument errors. Alternate I additional instrumentation should be used to confirm trending of PCS conditions.

The majority of these instruments are environmentally qualified which means they have been tested to survive a LOCA or MSL8. The temperatures seen in the lower layer of air are significantly lower than a LOCA or MSL8. Therefore, instruments located in the lower layer will operate satisfactorily.

As can be seen from the table there are some instruments that have either conduit, process tubing or instruments themselves in the hot layer of air. The following discussion will show that sufficient instruments are available to safely shutdown the plant. Steam Generator Pressure For a right channel cable tray fire, left channel steam generator pressure instruments are available for both steam generators (PT-0751C and PT-0752C).

For a left channel cable tray fire, PT-0751 O and its cables are located in the hot layer. However, the corresponding instrument for Steam Generator 8 (PT-07520), located 15 feet from PT-0751 O is not affected.

Since steam generator pressure would be the same in both steam generators PT-07520 can be used as sufficient indication for steam generator pressure.

Steam Generator Level For a right channel cable tray fire, left channel steam generator level instruments are available for both steam generators (LT-0751 C and L T-0752C).

Wide range steam generator level is available with LT-0757A and LT-0758A.

For a left channel cable tray fire,L T-0751 Os cables are located in the hot layer. In addition, wide range steam generator level instruments L T-07578 and L T-07588 have cables that extend into the hot layer in the stairwell area. Reference/Comment

.. ; l'OWERIN6 MICHl6RN'S l'R06RESS Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET EA-GWS-90-002 Sheet 18 of __ 1_9_ Rev# ____ o ___ _ Reference/Comment Table4 lnst./fube Conduit Conduit In Hot Layer? EQuipment ID Description Elevation Elevation Number Route lnst./fube Conduit

P.l"-i6'1S*it=::.

Steam Gen. A Pressure 601*-10* 599*-a* C0731 CV212,214 Yes No :;::::t,t:;i}ii)j:Ai:::

Steam Gen. A Level 601*-10* 599*_3* C0735 CV212,214 Yes No Steam Gen. A Pressure 600*-9* 599'-3" C0737 3CV212,214 No No ::::::i:..r..:P.1.$!1:G:::

Steam Gen. A Level 600*-9* 599'-3" C0741 3CV212,214 No No PT-0752A Steam Gen. B Pressure 601*-10* 599*-a* C0723 CV212 Yes No LT-0752A Steam Gen. B Level 601*-10* 599'-3" C0725 CV212 Yes No PT-0752C Steam Gen. B Pressure 600'-9" 599'-3" C0727 3CV212 No No LT-0752C Steam Gen. B Level 600*-9* 599*-a* C0729 3CV212 No No Steam Gen. A W.R. Level 600'-9*

C4083 CV212,214,216 No No Steam Gen. B W.R. Level 600*-9*

C4085 CV212,214,216 No No :::::::t:T:-::C.t.itt:::::

Steam Gen. A Level 601*-10* 599*.3* C0733 CV212,214 Yes No Steam Gen. B Level 600'-6" 599'-3" C0739 3CV212,214,216 No No Pressurizer Level* 600'-6" 599'-3" C0166 CV212, CV214 No No Pressurizer Wide Range Level 601'-6" 599*-a* FLEX CV212,214 Yes No :::::P.:f:;i}tu:t:Ai:::

Pressurizer Pressure

  • 600'-6* 599*.3* C0166 CV212,214 No No Pressurizer Pressure 601 *-s* 599*-a* C0165 CV212,214 Yes No
  • .*.*. *. *. Pressurizer Pressure 600*-s* 599*.3* C0166 3CV212 No No PT-0104A N. R. Pressurizer Pressure 600*-9* 599*.3* 3C0181 3CV212 No No PT-0105A W. R. Pressurizer Pressure 600*.9* 599*_3* ??? 3CV212 No No PT-07518 LT-07518 PT-07510 LT-07510 PT-07528 LT-07528 PT-07520 LT-07520

... . ..

LT-0703 LT-0704 LT-01018 LT-0103 PT-01018 PT-01028 PT-01020 PT-01048 PT-01058 Steam Gen. A Pressure 599*-2* Steam Gen. A Level 599'-2* Steam Gen. A Pressure 601 '*6* Steam Gen. A Level 599'-3" Steam Gen. 8 Pressure 599'-2" Steam Gen. 8 Level 599'-2" Steam Gen. 8 Pressure 599'-2" Steam Gen. 8 Level 599'-2" Steam Gen. A W.R. Level 599'-2" Steam Gen. 8 W.R. Level 599'-2" Steam Gen. A Level 599'-2" Steam Gen. 8 Level 599'-2" Pressurizer Level* 599'-2" Pressurizer Wide Range Level 599'-2" Pressurizer Pressure*

599'-2" Pressurizer Pressure 599'-2" Pressurizer Pressure 599'-2" N. R. Pressurizer Pressure 599'-2" W. R. Pressurizer Pressure 599'-2" Located in Main Part of Room -I I Located in Stairway -l:;:;:=:::;:::::;::::J 602*-o* 602*-o* 602'-0" 602'-0" 599'-3" 599'-3" 599'-3" 599'-3" 602'-0" 602'-0" 599'-3" 602'-0" 599'-3" 599'-3" 599'-3" 599'-3" 599'-3" C0732 CV21 O,CV222,224 No Yes C0734 CV21 O,CV222,224 No Yes C0740 4CV2-10,222 Yes Yes C0742 4CV210,222 No Yes C0724 CV210,222 No No C0276 CV210,222 No No C0728 4CV210,222, 224 No No C0730 4CV210,222, 224 No No C04082 CV210,222,224,22E No Yes C04084 CV210,222,224,22E No Yes C0736 CV210,222 No Yes C0744 4CV210,222, 224 No Yes C0169 CV210,222 No No C0746 CV210,222,224 No Yes C0169 CV210,222 No No C0169 CV210,222 No No C0172 4CV210,222, 224 No No 3C0180 4CV210,222, 224 No No C1460 4CV210 222 224 No No

  • Non Environmentally Qualified.

... . : '

POWER Palisades Nuclear Plant ANALYSIS CONTINUATION SHEET EA-GWS-90-002 Sheet 19 of 19 POUIERIN6 MICHl68N'S PR06RESS Rev# ____ o ___ _ Regarding the wide range steam generator level instruments, during normal shutdowns, steam generator levels do not usually go below the narrow range instrumentation.

Therefore shutdown can be accomplished without wide range steam generator level indication.

Regarding L T-0751 D, the corresponding instrument for Steam Generator 8, (LT-07520) located a minimum of 15 feet from L T-0751 D is not affected by the fire. In addition, the operators have other indications as to the adequacy of the Steam Generator function e.g-. PCS temperatures, main steam flows and feedwater flow. Pressurizer Pressure For a right channel cable tray fire, left channel wide range and narrow range pressurizer pressure instruments are available (PT-0104A and PT-0105A).

For a left channel cable tray fire, right channel wide range and narrow range pressurizer pressure instruments are available (PT-01048 and PT-01058).

Pressurizer Level For a right channel cable tray fire, left channel pressurizer level instrument LT-0102 has instrument tubing that extends into the hot layer. There is a possibility that the water in the process tubing will flash to steam since the upper layer temperature is above the saturation temperature at this pressure.

What is expected to happen is that the heat will be conducted away by the tubing during the short period of time the process tubing is exposed to the hot layer. This is based on several reasons: 1. Only a short section of the tubing (approximately 2 feet) is in the hot layer. 2. The section of tubing in the hot layer is mounted on the wall, thus its temperature will more closely approximate the wall temperature seen in graph 2. 3. The tubing is only in the hot layer for approximately 1 minute (see graph 4). 4. The upper layer air temperature is only above saturation for a maximum of 200 seconds (graph 2). Even if some flashing would occur, transmitter accuracy would recover after approximately 1 minute when the hot layer rose back up (see graph 4). This provides adequate guidance to the operators to safely shut down. In addition L T-0101 A is available to provide pressurizer level indication should L T-0102 fail. For a left channel cable tray fire, right channel pressurizer level instrument LT-0103 has cables that extend into the hot layer. LT-0101 B is available to provide Pressurizer level indication should L T-0103 fail. This provides adequate information to safely shut down the plant. CONCLUSION This analysis has shown that based on the amount and type of combustibles and type of ignition source, a fire in the Containment Air Room is extremely unlikely.

If a fire were to occur it would be most likely a small self extinguishing fire that generates dense smoke. If a much larger fire were to occur, there will still be enough instruments available to the operators to safely shutdown the plant. Reference/Comment

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