ML20062C868

Forwards IE Circular 78-18

ML20062C868
Person / Time
Site:	Bailly
Issue date:	11/06/1978
From:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	Shorb E NORTHERN INDIANA PUBLIC SERVICE CO.
References
NUDOCS 7811150044
Download: ML20062C868 (1)

Text

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, PDW' p4 ** ""We, UNITt:0 STATES y .q, ,2% NUCLEAR REGULATORY COMMISSION j ,Iff.f.i y REGloN Hi m nooSEVELT RoAo

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Docket ho. 50-367 110_V 01978 Northernqndl Public Service -

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-- l ATT!s: Mr. Eugene M. Shorb "l Senior Vice President 5265 Echman Avenue Hammond, IN 46325 Gentlemen:

The enclosed IE Circular No. 76-16 is forwarded to you for infor-mation. No specific action is requested and no written response is required. "If you desire additional information regarding this matter, please contact this office.

Sincerely,

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[Aames G. Keppler Director I

Enclosures:

1. IE Circular No. 78-18

2. List of IE Circulars Issued in 1970 oc w/eticls:

Central Files Director, NRR/DPH Director, NRR/ DOR PDR Local PDR

1. SIC TIC hr. Dean Hansell, Office of Assistant Attorney General 7'n 7 81115 0 6 9'L/ F)

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U.S. NUCLEAR RICULATORY C0!CIISSION OFFICE OF INSPECTION AND ENFORCE!IEPT

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REGION III IE Circular No. 78-18 ..

November 6, 1978 i UL TIRI TEST

Background

on Septe=ber 15,197E, a fire test of a full-scale vertical cable tray array was conducted at the Underwriters Laboratory (UL) near Chicago, Illineis. It was part of the fire protection research program managed by Sandia Laboratories under NRC contract. The purpose of the test was to demenstrate the effectiveness of area sprinklers and cable tray fire barriers constructed of ceramic fiber blankets in preventing damage to cables as a result of an exposure to a flammable liquid fire. The test resulted in damage tc seme electrical cables.

Dis:ussicn The configuration of the fire test was selected to simulate a section of a plant area with vertical cable trays containing redundant safety divisions arranged such that the redundant divisions could be simul-taneously exposed to a potential fire resulting from an inadvertent spill ef fla==able liquid in the area. The arrangement of the cable trays and the designation of the redundant tray divisions is shown in Figure 1.

Figure 2 shows 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 from floor to ceiling in accordance with the manu-facturer's recoemendations. The sprinkler and detector arrangement was as permitted by NTPA Code. However, no water was actually used at any time during this test due to the failure of some sprinkler heads to actuate, as explained below.

Each sprinkler location in the test arrangement contained chree nominally identical temperature sensing sprinkler heads with fusible links adjacent to an open sprinkler head which was connected te a manual water supply valve. The temperature sensing heads were wired to signal when their links fused. Af ter all three temperature sensing heads at a given loca-tion activated, then the water supply for the open head was to be manually adcitted. The sprinklers were of a type which actuate at the slow end of acceptance for reaction time. The test procedure required that all three temperature sensing heads had to activate before water would be turned on. In this way, it was expected to get some data on variability in the response time of identical sprinklers.

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LE Circular No. 78-18 ' liovember 6, 1978 Test Details The test was started by igniting the eve gallons of heptane that was poured into the floor pan. A fully developed fire occurred almost immediately. The ceiling smoke detector alarmed in about 15 seconds.

In about 50-60 seconds, two of the three temperature sensing sprinklers located between the vall and cable trays I and 2 activated. The fire between cable trays 1, 2, 3, and 4 appeared most intense, apparently because of a chimney effect between the four trays. The flames between cable trays 3 and 5 did not appear to be so intense. 'the ceramic fiber blanket absorbed scme of the heptane so that after the heptane in the pan burned, most of the flame seemed to come from the bottom outside surf ace of the ceramic fiber blasket. .No additional temperature 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 into the test there was an indication of a short 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.

Preliminary Results and Analyses i

Preliminary infermation indicates that the flammable liquid or flames penetratad the protective barriers at the bottom of the vertical trays and caused fire damage to the polyvinyl chloride insulation on cables

) in four of the five trays.

On subsequent 500-volt zegger tests, it was found that another cable in tray 2 had also experienced some damage, as evidenced by a conductor to ground short.

The most probsble cause of the fire damage in certain cable trays appears to be related to the absorption 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 ignition apparently occurred via the small opening at the floor or through a vapor / air path within the joints. There is some indication that some cable damage was caused by absorption of heptane on the inside of the barrier (vicking effect) and its ignition which heated a cable tray ladder rung, causing damage to a cable in contact with the rung. The ingress of the beptane inte the ceramic fiber needs to be further evaluated since this appears to be the most significant i..tlure mode.

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IE Circular No. 76-18 November 6, 1978

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Tentative Conclusions ,

The test results are still being analyzed, and it would be premature to establish firm conclusions at this time; hovever, the results now available indicate th6t the following areas of the fire protection program need close consideration:

1. To protect against spills of flam=able liquids, barriers or curbs may be needed to prevent entry of the flammable liquid behind fire barriers. A wick effect may also need to be considered in the design of fire barriers.

2. Some small fires may not actuate sprinkler heads. To reduce this Possibility in sprinkler systems to be installed, fast respense sprinkler heads should be considered (less than approxinately

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3 minutes in the UL Standard 199 " Automatic 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 importanca.. The path of the air movenent in the area influences the actuation of such devices and should be considered in the system layout.

The final results of this test will be issued when the analysis of the test is complete.

This circular is being issued for infermation only. No specific action is requested and no written response is required. If you desire addi-tional information regarding this matter, contact the Director of the appropriate NRC Regional Office.

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IE Circular No. 78-18 November 6, 1978 LISTINC OF IE CIRCULARS ISSUED IN 1978 Circular Subject Date Issued To No. of Issue 76-01 Less of Well Logging 4/5/78 All Eelders of Source Well Logging Source Licenses 76-02 Proper Lubricating 011 4/20/78 All Holders of for Terry Turbines Reactor OLs or cps 78-03 Packaging Greater Than 5/12/76 All Holders of Type A Quantities of Reactor OLs, cps, Low Specific Activity Fuel Cycle, Radioactive Material rPriority I Material for Transpert and Waste Disposal Licenses 76-04 Installation Error That 5/15/78 All Holders of Could Prevent Closing of Reactor OLs or Fire Doors cps 78-05 Inadverte.nt Safety Injection 5/23/78 All Holders of

, During Cooldo c Reactor OLs or cps 76-06 Potential Com=en Mode '5/23/78 All Holders of Flooding of ECCS Equipment Reactor OLs or Rooms at BWR Tacilities cps 76-07 Damaged Conponents of a 5/31/78 All Holders of Bergen-Paterson Series Reactor OLs or 25000 Eydraulic Test cps Stand 76-0E Environmental Qualification 5/31/78 All Holders of of Safety Related Equipment Reactor OLs or at Nuclear Power Plants cps 76-09 Arcing of General Electric 6/5/78 All Holders of ,

Company Size 2 Contactors cps  !

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l IE Circular No. 78-18 November.6, 1978 I LISTING OF IE CIRCULARS ISSUED IN 1978 Circular Subject Date of Issued to No. Issue 75-10 Control of Sealed 6/14/78 All Medical Sources Used in Licensees in Radiation Therapy Categories G and G1 76-11 Recirculation M-G 6/15/78 All Holders of 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 cps for plants with a EPCI Terry Turbine 75-13 Inoperability of Multiple 7/10/78 All Holders of Service Water Pumps Reactor OLs and cps except for plants located in: AL, AK, CA, FL, GA, LA, MS, SC 78-14 HPCI Turbine Reversing 7/12/78 All Holders of BWR Chanber Hold Down Bolting OLs or cps for plants with a EPCI Terry Turbine excepting Duane Arnold and Monticelle 76-15 Checkvalves Tail to 7/20/78 All Holders of close In Vertical Reactor OLs or cps Position 78-16 Linitorque 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 Reactor OLs.

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