ML17331A132
| ML17331A132 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 11/06/1978 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Dolan J AMERICAN ELECTRIC POWER CO., INC. |
| References | |
| NUDOCS 7811150061 | |
| Download: ML17331A132 (13) | |
Text
CENTRAL FILES Loci.et ho. 50-315 Docket No. 50-316 NOY 6 t978 Araerican Electric Power Service Corporation indiana arid tU.chigan Power Company A'I'f(;:
Fir. John E. Dolan, Senior Executive Vice President Engineering 2 &r oadway 5'ew worl;,
HY 1000I(
( entlemen:
'the enclosed IE Circular Hc. 7U-18 is forwarded to you for infor-mation.
t'o specific action is requested and no written response i required. If you desire additional information regarding this matter, please contact this office.
Sincerely, James G. Eeppler Director
Enclosures:
- l. IE Circular ho. 78-18
- 2. List of IE Circulars Issued in 197o cc w/encl tir. D. V. Shaller, Plant Rancher Central Files
- Director, BRR/DPN
DATE~
d Dismore Come Better (.nvi Citizens nment RIII Fiorel&/ls 11/6/7U ler NRC Form 318A (RIK) (5-76) NRCM 02040
- V. S. GOVERNMENT PRINTING OFFICE:
1978-253 818
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NUCLEAR REGULATORY COMNISSION OFFICE OF INSPECTION AND ENFORCEtKNT REGION III UL PIRE TEST
Background
IE Circular No 78-18 November 6, 1978 On September 15, 1978, a fire test o'f a full-scale vertical cable tray array was conducted at the Underwriters Laboratory (UL) near Chicago, Illinois. It was part of the fire protection research program managed by Sandia Laboratories under NRC contract.
The purpose of the test was to demonstrate 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 to some electrical cables.
Discussion The configuration of the fiie 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 of flammable liquid in the area.
The arrangement of the cable trays and the designation of the redundant tray divisions is shown in Figure l.
Figure 2 shows the location of the fire detectors and the three groups of sprinklers.
Each of the five cable trays contained cable insulated~
with polyvinyl chloride and was enclosed in a separated ceramic fiber blanket fire barrier from floor to ceiling in accordance with the manu-facturer's recommendations.
The sprinkler and detector arrangement was as permitted by NFPA 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 three nominally identical temperature sensing sprinkler heads with fusible links adjacent to an open sprinkler head which was connected to a manual water supply valve.
The temperature sensing heads were wired to signal when their links fused.
After all three temperature sensing heads at a given loca-tion activated, then the water supply for the open head was to be manually admitted.
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
IE Circular Tfo. 78-18 November 6, 1978 Test Details The test was started by igniting the two 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 wall and cable trays 1 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 some of the heptane so that after the heptane in the pan burned, most of the flame seemed to come from the bottom outside surface of the ceramic fiber blanket.
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 Preliminary information indicates that the flammable liquid or flames penetrated the protective barriers at the bottom of the vertical trays and caused ffre damage to the polyvinyl chloride insulation on cables in four of the five trays.
On subsequent 500-volt megger 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 probable 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 puncture 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 go5nts.
There is some indication that some cable damage was caused by absorption of heptane on the inside of the barrier (wicking 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 heptane into the ceramic fiber needs to be further evaluated since this appears to be the most significant failure mode.
IE Circular No. 78-18 November 6, 1978 Tentative Conclusions The test results are still being analyzed, and it would be premature to establish firm conclusions at this time; however, the results now available indicate that the following areas of the fire protection program need close consideration:
l.
To protect against spills of flammable 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 response sprinkler heads should be considered (less than approximately 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 importance.
The path of the air movement 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 information 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.
1 Attachments:
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IE Circular No. 78-18 November
.6, 1978 LISTING OF IE CIRCULARS ISSUED IN 1978 Circular No.
78-01 Sub5 ect Loss of Mell Logging Source Date of Issue 4/5/78 Issued To All Holders of Mell Logging Source Licenses 78-02 Proper Lubricating Oil for Terry Turbines 4/20/78 All Holders of Reactor OLs or CPs 78-03 Packaging Greater Than Type A Quantities of Low Specific Activity Radioactive Material for Transport 5/12/78 All Holders of Reactor OLs, CPs, Fuel Cycle, Priority I Material and Maste Disposal Licenses 78-04 78-05 Installation Error That 5/15/78 Could Prevent Closing of Fire Doors Inadvertent Safety In)ection 5/23/78 During Cooldown All Holders of Reactor OLs or CPs All Holders of Reactor OLs or CPs 78-06 Potential Common Mode Flooding of ECCS Equipment Rooms at BMR Facilities 5/23/78 All Holders of Reactor OLs or CPs 78-07 Damaged Components of a Bergen-Paterson Series 25000 Hydraulic Test Stand 5/31/78 All Holders of Reactor OLs or CPs 78-08 78-09 Environmental Qualification of Safety Related Equipment at Nuclear Power Plants Arcing of General Electric Company Size 2 Contactors 5/31/78 6/5/78 All Holders of Reactor OLs or CPs All Holders of CPs
IE Circular No. 78-18 November.6, 1978 LISTING OF IE CIRCULARS ISSUED IN 1978 Circular Sub)ect No, Date of Issue Issued to 78-10 78-11 78-12 78-13 Control of Scaled Sources Used in Radiation Therapy Recirculation M-G Set Overspeed Stops HPCI Turbine Control Valve Lift Rod Bending Inoperability of Multiple Service Water Pumps 6/14/78 6/15/78 6/30/78 7/10/78 All Medical Licensees in Categories G
and Gl All Holders of BWR OLs or CPs All Holders of BWR OLs or CPs for plants with HPCI Terry Turbine All Holders of Reactor OLs and CPs except for plants located in: AL, AK, CA~ FLj GAj LAj YS~
SC 78-14 78-15 78-16 78-17 HPCI Turbine Reversing Chamber Hold Down Bolting Checkvalves Fail to Close In Vertical Position Limitorque Valve Actuators Inadequate Guard Training/
Qualification and Falsified Training Records 7/12/78 7/20/78 7/26/78 10/13/78 All Holders of BWR OLs or CPs for plants with a HPCI Terry Turbine excepting Duane Arnold and Monticello All Holders of Reactor OLs or CPs All Holders of Reactor OLs or CPs All Holders of and applicants for Reactor OLs.