ML20062C891
| ML20062C891 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 11/06/1978 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Madgett J DAIRYLAND POWER COOPERATIVE |
| References | |
| NUDOCS 7811150066 | |
| Download: ML20062C891 (1) | |
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NUCLEAR REGULATORY COMMISSION 4
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I Docket No. 50-409 Dairyland Power Cooperative ATIN:
Mr. J. P. hadgett General Manager 2615 East Avenue - South s\\
La Crosse, h1 54601 Gentlemen:
The enclosed IE Circular No. 76-18 is forwarded to ycu for infor-mation. ho specific action is requested and no written response is 1
required. If you desire additional information regarding this matter, please contact this office.
Sincerely, G. _.. M M =dr amesG'.Ke3
[ Director
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Enclosures:
- 1. IE Circular ho. 76-le i
- 2. Lis,t of IE Circulars Issued in 1970 cc w/encls:
I hr. E. E. Shi=shak, Plant Superintendent Central Files Director, NRR/DPM Director, hRR/ DOR PDR Local PDR NSIC TIC Anthony Roiscan, Esq.,
Attorney 7till54$6'/V
U.S. NUCLEAR REGULATORY CONtISSION OFFICE OF INSPECTION AND ENFORCEtIEFT RECION III
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IE Circular Ro. 78-18 November 6, 1978 UL FIRI TEST
Background
on Septe:ber 15,197E, e fire test of a full-scale vertical cable tray array was conducted at the Underwriters Laberatory (UL) near Chicago, Illineis. It was part of the fire pretection research pregra: managed by Sandia Laberateries under !!RC contract. The purpese of the test was te demenstrate the effacti"eness cf area sprinklers and cable tray fire barriers cehstructed of ce amic fiber blankets in preventing da age to cables as a result of an exposure to a flac=able liquid fire. The test resulted in datage te sete electrical cables.
Discussion The cenfiguratien of the fire test was selected te simulate a section of a plant area with vertical cable trays containing redundant safety divisiens arranged such that the redundant divisions could be sicul-taneously exposed te a potential fire resulting from an inadvertent spill of flat =able liquid in the area. The arrange:ent of the cable trays and the designation of the redundant tray divisions is shewn in Figure 1.
Figure 2 shews the locatien of the fire detectors and the three groups of sprinklers. Each of the five cable trays contained cable insulated.
with polyvinyl chieride and was enclosed in a separated ceramic fiber blanket fire barrier fro = floor to ceiling in accordance with the manu-facturer's rece=sendatiens. The sprinkler and detector arrange:ent was as permitted by NFPA Code. However, ne water was actually used at any time during this test due to the failure of some sprinkler heads to actuate, as explained belev.
Each sprinkler location in the test arrange ent contained three no:inally I
identical te:perature sensing sprinkler heads with fusible links adjacent te an open sprinkler head which was connected te a manual water supply valve. The te:perature sensing heads were wired to signal when their links fused. After all three te=perature sensing heads at a given loca-tien activated, then the water supply for the open head was to be manually ad itted. The sprinklers were of a type which actuate at the slev and of acceptance for reaction time. The test procedure required that all three te:perature sensing heads had to activate before water would be turned en.
In this way, it was expected to get se=e data en variability in the respense time of identical sprinklers.
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4 IE Circular No. 78-18 November 6, 1978 Test Details The test was started by igniting the two gallons of heptane that was poured into the floer pan. A fully developed fire occurred almost itsediately. The ceiling smoke detector alarmed in about 15 secends.
In about 50-60 seconds, two of the three te=perature sensing sprinklers located between the wall and es??e trays 1 and 2 activated. The fire between cable trays 1, 2, 3, at a appeared most intense, apparently because of a chicavy effect between the four trays. The flates between cable trays 3 and 5 did not appear to be so intense. The ceramic fiber blanket absorbed some of the heptane so that af ter the heptane in the pan burned, mest of the fla:e seemed to ce=e free the botto: outside surf ace of the cera=ic fiber blanket. No additional te=perature sensing sprinkler heads at any location activated; thus, the sprinkler water supply was not turned on for any of the three sprinkler locations.
The apparent slow response of the third temperature sensing sprinkler is being investigated, since this was not intended to be a slow response sprinkler.
At about 3 minutes inte the test there was an indication cf a shere circuit in cable tray 3, which was probably caused by the fire. After 5-7 minutes the height of the flames appeared to subside; however, residual flames continued for about 40 minutes.
Pre 11 inary Results and Analyses Preliminary infer =ation indicates that the flam=able liquid er fla:es penetrated the protective barriers at the botto: of the vertical trays and caused fira damage to the pelyvinyl chloride insulatica on cables in four of the five trays.
On subsequent 500-velt zegger tests, it was found that ancther cable in tray 2 had also experienced some damage, as evidenced by a conductor to ground short.
The cost probable cause of the fire da: age in certain cable trays appears te be related to the abscrptien or seepage of heptane under the ceramic fiber blanket at the juncture with the floor. Once the heptane entered the interior regions of the cable tray, then ignitien apparently occurred via the s=all opening at the floor or through a vaper/ air path within the joints. There is some indication that se=e cable da: age was caused l
by absorptf en of heptane on the inside of the barrier (vicking effect) and its ignition which heated a cable tray ladder rung, causing da: age te a cable in centact with the rung. The ingress of the heptane inte the ceramic fiber needs to be further evaluated since this appears te I
be the most significant failure mode.
9 IE Circular No. 78-18 November 6,1978 Tentative Conclusiens The test results are still being analyzed, and it would be premature to establish fir = conclusions at this time; however, the results now available indicate that the following arer,s of the fire protection pregra: need close consideration:
1.
To protect against spills of flammable liquids, barriers er curbs may be needed to prevent entry of the fla==able liquid behind fire barriers. A vick effect may also need to be considered in the design of fire barriers.
2.
Sece stall fires may not actuate sprinkler heads. Te reduce this possibility in sprinkler systets to be installed, fast respense sprinkler heads sheuld be considered (less than approximately 3 minutes in the UL Standard 199 " Auto =stic Sprinklers for Fire Protection Service").
3.
The location of the fire detection devices and the sprinkler heads relative to the fire and components being protected is of great importance. The path of the air sevement in the area influences the actuatien of such devices and should be considered in the syste= laycut.
The final results of this test will be issued when the analysis of the test is cecplete.
This circular is being issued for infer =ation only. No specific actien is requested and no written response is required. If you desire addi-tional infer =atien regarding this matter, contact the Directer of the appropriate NRC Regional Office.
Attach ents:
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IE Circular No. 78-18 November 6, 1978 i
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LISTING OF IE CIRCULAPS ISSUED IN 1978
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Circular Subject Date Issue'd To 2 '
No.
of Issue 4*'
78-01 Loss of Well Logging 4/5/78 All Helders of Source Well Logging Source Licenses
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78-02, Proper Lubricating 011 4/20/78 All Holders of for Terry Turbines React.or OLs or cps 78-03 Packaging Greater Than 5/12f78 All Helders of Type A Quantities of Reactor'OLs, cps, Low Specific Activity Fuel Cycle, Radioactive Material Priority I Material for Transpert and Waste.Dispesal Licenses 76-04 Installation Error That
-5/15/78 All Holders of Could Prevent Closing of Reactor OLs or Fire Doors CPa 7a 05 Inadvertent Safety Injection 5/23/78 All Holders of During Cocidown Reactor OLs er cps 5/23/78 All Helders of 76-05 Potential Coc=en Mode Flooding of ECCS Equipment Reactor OLs or
Roccs at BWR Pacilities cps 78-07 Da: aged Components of a 5/31/78 All Holders cf Bergen-Paterson Seriew Reactor OLs or 25000 Hydraulic Test '
cps Stand s
V 75-DE Environmental Qualiffestien 5/31/78 All Holders of of Safety Related Equipment Reactor OLs er at Nuclear Power Plants cps
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78-09 Arcing of General Electric 6/5/78 All Holders of Company Size 2 Contacters cps l
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IE Circular No. 78-18 November 6, 1978
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LISTING OF IE CIRCULARS ISSUED IN_1978 Circular Subject Date of Issued to No.
Issue 78-10 Control of Sealed 6/14/78 All Medical Sources Used in Licensees in Radiation Therapy Categories C and G1 78-11 Recirculatien M-G' 6/15/76 All Holders cf Set Overspeed Stops BWR OLs or cps 76-12 EPCI Turbine Control 6/30/78 All Holders of Valve Lift Rod Bending BWR OLs or C1's for plants with HPCI Terry Turbine 75-13 Ineperability of Multiple 7/10/78 All Holders of Service Water Pumps Reactor OLs and cps except for plants located in: AL, AK, CA TL, CA, LA MS, SC 78-14 HPCI Turbine Reversing 7/12/78 All Helders cf EWR Chamber Hold Down Bolting OLs or cps for plants with a EPCI Terry Turbine excepting Duane Arneld and Monticelle 78-15 Checkvalves Fail to 7/20/78 All Holders cf Close In Vertical Reacter OLs er cps Position 78-16 Liciterque valve 7/26/78 All Holders of Actuators Reactor OLs or cps 78-17 Inadequate Guard Training /
10/13/78 All Holders of Qualification and Falsified and applicants Training Records for Reacter OLs. i I
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