ML20062D697
| ML20062D697 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 11/06/1978 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| References | |
| NUDOCS 7811290160 | |
| Download: ML20062D697 (1) | |
Text
- - -
[0-277 PM s>* R80,
UNITED Tfm(ES 9
p
., g NUCLEAR REGULATORY-COMMissl0N i
gl(
REG)CN I i /
'. -($ '. - y'j 431 PARK AVENUE g,. f. j g.]
nino or==Uss A.eEnnsvovAn A i 4os t
Docket Nos. 0-2778' 5
Philadelphia Electric Company ATTN: Mr. S. L. Daltroff Vice President Electric Production 2301 Market Street Philade'.phia, Pennsylvania 19101 Gentlemen:
3 The enclosed IE Circular No. 78-18 is forwrded to you for informa-tion. No specific action is requested and no written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, Mm Boyce H. Grier
' Director
Enclosures:
1.
It Circular No. 78-18 2.
List of IE Circulars Issued in 1978 cc: (w/encis)
W. T. Ullrich, Station Superintendent Troy B. Conner, Jr., Esquire Eugene J. Bradley, Esquire Raymond L. Hovis Esquire Warren Rich, Esquire 7811290 /40 4
UNITED STATES NUCLEAR REGULATORY COMM.tSSION OFFICE OF INSPECTION AND EhFORCEMENT WASHINGTON, D. C.
20555 IE Circular 78-18 Date: November 6, 1978 Page 1 of 3 UL FIRE TEST
Background
On September 15, 1978, a fire test of 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 flamable liquid fire. The test resulted in damage to some electrical cables.
Discussion 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 of flamable 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 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 manufacturer's recomendations. 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.
l l
i Date: November 6, 1978 Page 2 of 3 i
Test Details i
The test was started by igniting the two gallons of heptane that was i
poured into the floor pan. A fully developed fire occurred almost
~
imediately. The ceiling smoke detector alarmed in about 15 seconds. In about 50-60 seconds, two of the three temperature sensing sprinklers i
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 i
e because of a chimney effect between the four trays. The flames between i
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 i
pan burned, most of the flame seemed to come from the bottom outside surface of the ceramic fiber blanket. No additional temperature sensing 1
4 i
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 L
i being investigated, since this was not intended to be a slew response sprinkler.
i j
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 f1&mes appeared to subside; however, j
l residual fiames cont'..ued for about 40 minutes.
1 Preliminary Results and Analyses j
preliminary information indicates that the flamable liquid or flames penetrated the protective barriers at. the bottom of the vertical trays I
i and caused fire damage to the polyvinyl chloride insulation on cables in four of the five trays.
j 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.
a The most probable cause of the fire damage in certain cable trays appears
[
to be related to the absorption or seapage of heptane under the ceramic.
l fiber blanket at the juncture with the floor. Once the heptane entered l
the interior regions of the cable tray, then ignition apparently occurred l
l via the small opening at the floor or thrcugh a vapor / air path within 1
the joints. There is some indication that some cable damage was caused I
by absorption of heptand 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 j
the ceramic fiber needs to be further evaluated since this appears to be i
the most significant failure mode.
J i
f i
i 1.
__,m,
I IE Circular 78-18 Date: November 6, 1978 Page 3 of 3 i
Tentative Conclusions j
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 considerazion:
j 1.
To protect against spills of flamable liquids, barriers or curbs may be needed to prevent entry of the flamable liquid behind fire barriers. A wick effect may also need to be considered in the
[
design of fire barriers.
l 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 j
s 3 minutes in the UL Standard 199 "Autcmatic Sprinklers for Fire ProtectionService").
j 3.
The location of the fire dotection 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 i
j system layout, t
The final results of this test will be issued when the analysis of the test is complete.
l 3
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.
Attachments-i 1.
Figure 1 2.
Figure 2 l
f i
f i
i
-,m.
. -,. ~.
,.__._.__r.--
._-,r..-
.,y
=.
l l
P 9
IE Circular No. 78-18 Date: November 6, 1978 Page 1 of 2 ENCLOSURE 2 LIST OF IE CIRCULARS ISSUED IN 1978 Circular Subject First Date Issued To No.
of Issue l
78-01 Loss of Well Logging 4/14/78 All Holders of Source Well Logging Source Licenses 78-02 Proper Lubricating 011 4/20/78 All Power Reactor for Terry Turbines Facilities with an Operating License (OL) or Construction Permit (CP) 78-03 Packaging Greatcr Than 5/12/78 All Power Reactor Type A Quantities of Facilities with an Low Specific Activity OL or CP; and all Radioactive Material Fuel Cycle, Priority I for Transport Materials and Waste Disposal Licensees 78-04 Installation Errors That 5/18/78 All Power Reactor l
Could Prevent Closing Facilities with an of Fire Doors OL or CP 78-05 Inadvertent Safety 5/26/78 All PWR Power 3
Injection During Reactor Facilities j
Cooldown with an OL or CP 78-06 Potential Comon Mode 5/31/78 All Power Reactor Flooding of ECCS Facilities with an
[
~
3 Equipment Rooms at OL or CP BWR Facilities 78-07 Damaged Components on a 5/31/78 All Power Reactor 5
i Bergen-Paterson Series Facilities with an 25000 Hydraulic Test Stand OL or CP 78-08 Environmental Qualifica-5/31/78 All Power Reactor tion of Safety-Related Facilities with an i
Electrical Equipment at OL or CP Nuclear Power Plants i
c,
IE Circular No. 78-18 Date: November 6, 1978 Page 2 of 2 ENCLOSURE 2(Continued)
LIST OF IE CIRCULARS ISSUED IN 1978 Circular Subject First Date Issued To No.
of Issue 78-09 Arcing of General Electric 6/8/78 All Power Reactor Company NEMA Size 2 Facilities with an Contactors OL or CP 78-10 Control of Sealed Sources 6/14/78 All Institutional Used in Radiation Therapy Medical Licensees 78-11 Recirulation M-G Set 6/15/78 All BWR Power Reactor Oversp'eed Stops Facilities with an OL or CP 78-12 HPCI Turbine Control 6/30/78 All Power Reactor Valve Lift Rod Facilities with an Bending OL or CP having a HPCI Terry Turbine 78-13 Inoperability of 7/10/78 All Power Reactor Multiple Service Facilities with an Water Pumps OL or CP 78-14 HPCI Turbine Re-7/17/78 All Power Reactor versing Chamber Facilities with an Hold Down Bolting OL or CP having a HPCI Terry Turbine excepting Duane Arnold and Monticello 78-15 Tilting Disk Check 7/24/78 All Power Reactor Valves Fail to Close Facilities with an with Gravity in Vertical OL or CP Position 78-16 Limitorque Valve 7/26/78 All Power Reactor Actuators Facilities with an OL or CP 78-17 Inadequate Guard 10/13/78 All Power Reactor Training / Qualification Facilities with an and Falsified Training OL; Susquehanna 1 & 2, Records Shoreham, and Salem 2 n
-~
~