ML20112G034
| ML20112G034 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 01/08/1985 |
| From: | Spangenberg F ILLINOIS POWER CO. |
| To: | Siegel B Office of Nuclear Reactor Regulation |
| References | |
| U-0775, U-775, NUDOCS 8501160158 | |
| Download: ML20112G034 (11) | |
Text
_.
"J U-0775 B51-85(01-08)-6 1A.120
/LLIN018 POWER COMPANY CLINTON POWER STATION. P.O. 80X 678, CLINTON, ILLINOIS 61727 Docket No. 50-461 January 8, 1985 Mr. B. L. Siegel Clinton Licensing Project Manager Licensing Branch No. 2 U.S. Nuclear Regulatory Commission Phillips Building - Room 136 Bethesda, MD 20814
Subject:
General Electric's Power Generation Control Complex Floor System Halon Fire Protection
Dear Mr. Siegel:
A position paper (attachment I) was ' developed by Niagara Mohawk, Gulf States Utilities, Pennsylvania Power & Light, and Illinois Power Company as a means to encourage the revision of the Halon concentration criterion for the Power Generation Control Complex (PGCC) floor system.
The proposal for a different Halon limit is based upon Halon suppression test results (attachment II) sponsored.by the NRC in 1981 which show a criterion of 6% Halon with a 10 minute duration is adequate.
A meeting in your offices during January, 1985 is requested so we
' can discuss the details and merits of this proposal.
Sincerely yours, F. A. Spangenberg Director - Nuclear Licensing and Configuration Nuclear Station Engineering RW/en Attachments cc: Regional Administrator Region III, USNRC NRC Resident Office Illinois Department of Nuclear Safety O
1 F
PDR 1
o U-0775 B51-85(01-08) 6 1A.120 I
Attachment I Page 1 of 2 Alternative Approach to NEDO 10466-A l;
The goal of this presentation is to show that a Halon (1301) concentration level of 6% and a holding time of 10 minutes is sufficient to extinguish a deep seated fire.
The PGCC floor modules are separated into distinct fire protection sones having individual Halon (1301) distribution systems. The installation of the floor modules is concluded by sealing the zones from each other. Physical constraints in some cases result in less than l-perfect sealing of these zones; hence the zone leak tightness and the
- Halon equipment capacity must be correlated. The Halon injection
. equipment'must be able to achieve a given Halon concentration within 10 seconds and then sustain that concentration for a given holding time.
The 20% concentration with a holding time of 20 minutes (20/20) is contained on page 4-25 of NEDO Document 10466-A (February,1979) but no reference was given so that the basis or circumstance could be studied 7
zin detail.
In 1981, Sandia National Laboratories conducted a series of Halon
_ (1301) suppression: tests on cable tray configurations per an NRC 1 contract (SAND 81-1785). The test results established that a Halon concentration of 6% with a holding time of 10 minutes (6/10) was
- sufficient for obtaining fire extinguishment and preventing subsequent reignition. This particular report was not released but the test
-summary was published in NUREC/CR-2607. The particular tests (SAND i
81-1785) were conducted in an'open room tray design'and the 6/10 was successful. We have reasoned that closed trays would be equally
- successful at 6/10 due to'the confinement and metal' mass of the floor trays (zones). We understand that NUREC CR-3656, " Evaluation of Suppression Methods for Electrical Cable Fire" will be published soon,
-perhaps.during the'first quarter of'1985, and that it supports the criterion'for a 6% Halon concentration sustained for a 10 minute period.
i The halon (1301) fire suppression systems for the PGCC floor modules were designed for total flooding of the protected volumes.- The physical conditions or constraints'of a PGCC floor module (zone) are more conducive to Halon extinguishment than the open room tray tarrangement_used in the Sandia tests.- Oxygen input is substantially reduced and the combustion product efflux (reduction) is inhibited within the PGCC floor Lodules when compared with the open room tray j
1 s
tests. The enclosed tray (PGCC)'is more effective in dissipating heat t
through the metal mass of the attached floor modules than the open room e
Ltray dispersion of ' heat into the air volume.
4
.m.
FI U- 0775 B51-85 ( 01-08)-6 1A.120 Attachment I Page 2 of 2 i
In summary, our analysis supports the acceptability of a lower
' Halon concentration (6%) and a reduced holding c:'me.
It seems prudent based on our analysis that a practical concentrat'on value of 6% Halon (1301) be ~ utilized (10 minute duration) to first ensure that adequate fire-inhibition is present and secondly that human occupation of the
' control room can occur as long as possible under extreme conditions.
.c
~
i i.
!~
i.
i m.
j f G Q fl-l % 6 ATTmHMENT 1r II.5.2 Nalon Suppression TGsto A series of nine tests we.-
conducted at Sandia National Laboratories to determine the ef fectiveness of Halon 1301 in suppressing flaming and deep-seated cable tray fires.34 This halogen compound is produced by E.I. DuPont de Nemours and Company, Incorporated and has the chemical formula CBrF.
Kalon 1301 has been extensively tested as a fire 3
suppressant.35 In addition to the retardant action on fires, it is believed that Malon 1301 presents less of a personnel hazard than carbon dioxide or nitrogen inerting systems.
According to human effects experiments conducted by Haskell Laboratories 36 the health hazard threshold for Ralon g} 1301 is 7 percent by volume.
The room volumetric concen-tration of Halon did not exceed 6 percent for this series of cable fire suppression tests.
The experimental facility used in all earlier tests had to be modified in order to install the various suppression systems to be tested.
One new feature of the facility was a vent-ilation system, installed to allow simulation of normal air ventilation and circulation in a room of a nuclear power plant.
The flow rate of the ventilation system, when used, was set to approximately 2100 ft3 per minute which provided an air turnover rate in the room of about once every'4.6 minutes.
Tests were conducted,in both the horizontal and vertical configuration of cable trays, and both JEEE-383 qualified (cross-linked polyethylene, 3 conductor) and unqualified (PE/PVC, 3 conductor) cables were used as in previous tests.
Trays were separated by 10.5 in. (27.6 cm).
" Dummy
- trays consisting of an insulating barrier were placed adjacent to the two trays (vertical tests) or above the top tray (hori-zontal tests) to provide reradiation of heat.
In these tests, i
the ignition tray was designated the donor tray, while the second tray was designated the acceptor tray.
Five-minute j
on-and-off-burn cycles using a total of 140,000 BTU /HR (41-kW) propane burners were used ' until a "well-developed" fire was started.
At this point, an insulating barrier separating *he two cable trays was removed and 1 minute later the Halon discharged The discharge rates complied with NFPA 12A-1980.3i The room was also sealed at the time of discharge as required.
Table VII summarizes the tests conducted as well as the result... Tests 50 and 59 used no Halon but instead allowed the fire to proceed until the ventilation system was t
1 J ]
.......... ~...._,... _ _ -_ --
~
TABLE VII Malon. Suppression Tests Summary Test Suppression Number Configuration Cable Type Nethod Results 56 Norizontal
-IFEE-383 45-minute soak No reignition after Qualified
,using Malon admission of fresh air 57 Norizontal Qualified 10-minute Halon No reignition soak 58 Norizontal Qualified No Malon: 45 self-quenched after minutes without 30 minutes i
ventilation 59 Norizontal Qualified No Halon: 10 Burning after 10 e
minutes without minutes ventilation 60 Morizontal Qualified 4-minute Halon Reignited when soak ventilated 61 Norizontal Unqualified 16-minute Halon No reignition I
soak 52 Vertical Unqualified 5-minute Halon No reignition 63 Vertical Qualified 4-minute Halon No reignition soak 64 Vertical Qualified Malon discharged No reignition but room continu-ounly vented f
i
turned on later.
In only one instance using Halon, Test 60,
?
did the cable insulation reignite after readmission of fresh l
air.
The soak time represents the amount of time the room was i
- sealed, i.e.,
time between discharge of Halon and readmission of fresh air using the ventilation system.
Halon 1301 was very effective in suppressing flames.
Figure 15 shows that 5 seconds after discharge the flames have been extinguished and all that remains is smoke and condensed water i
vapor.
Figure 16 taken from Test 61 shows the dramatic temp-erature drop in the flaming region as Halon is discharged.
j Ralon 1301 was not as raoid in suppressing deep-seated cable l
tray fires.
Figure 17 indicates that even after the Halon has i
been discharged the interior cable bundle temperature continues to rise, probably resulting from continued combustion of cable insulation.
The second increase in temp-l erature occurs after the readmission of air and reignition of the cable insulation.
Finally, Figures 18 and 19 show the dynamic mass loss of cable
{
f' insulation in the donor trays for Tests 57 and 59.
These two tests were identical in every respect except that in Test 57 a 10-minute Halon~ soak was provided whereas no Halon was used in t
Test 59.
However, only 3.7 kg of insulation was lost when i
Halon was used (most of it before Halon discharge) compared to I
a loss of 6 kg when the fire was allowed to self-extinguish.
j Clearly, Halon is an effective fire suppressant agent even for
}
deep-seated cable fires.
g Major Findirigs I
six very obvious but important items stand out among all conceivable findings from the Halon suppression systems tests.
They number as follows:
s 1.
No damage to, or reduction in, the acceptor tray l
cables' current-carrying capacity as a result of Halon was observed in any of the tests.
2.
In all of the tests in which it was used, the Halon effectively extinguished fires in both the acceptor and donor trays.
In only one test (60) was a flame rekindled in either tray after the room was ventilated.
l l
l l
4, l
l O
~40~
l
- _.. _ _ _ _ _ _. ~. _ _ _ _ _ _ _. _. -. - _
-ZP-uoT6ag Su1meTJ uy dosa asngesadmas i
ST asn5T4 DEGREES CELSIUS a
a a
u e
a e
a w
e e
o m
O O
o o
o O
o o
o o
e O
O O
O O
O O
O O
O O
A O
a C
a 2
O BURNERSQGNITED j
g C
m a
HALON DISCHARGED g
hO
~
I (O
m >m M
o 3
d
>=
Wm g
p1
~
~
m 32 3O i
-2 m3 i
g 3 N g
O 4O 2
m2 E4
'm >F
~
m I
l e
m I
3 4
>3 O
4>
C<
3 I
a mm m
a i
i a
l I
m E
~
~
O 2
=
m r"
O 2
I e
i e
i i
i i
i i
i O
e O
g
---..-.--,..w--.
,--.......n-,
.._.-._.,-..,,.-,,.v.
-..._--.----.en.,....
_c,_
satqe3 Jo uoitiu6 ag T
pur asyg passas-daaa Jo uoigesiput f.I a2n6TJ
[
DEGREES CELSIUS a
4
- - i a
M e
m o
M.
e e
O m
?
O O
O O
O O
O O
O O
en O
O O
O O
O O
O O
O O
A O--
BURNERS IGNITED eO m
m m
a m
> a.
o Ooe a
W m
j 30 4>
HALON DISCHARGED C 03 i
g O
3 m
a-a 22 N
DO E
m 43 m
i ON
{
_2 U
mO O
22 E
a4 i
3 mp u
3 r-i c
H 44 m
mm M
&o 14
~
m us 3*
t i
i C E k,
mz t
m mC
^
O 4
I m
2 a
i m
P o
2 3
a (A
0 O
i!
>x
.l*
4 TEST +57, IEEE-383 CABLE, HORIZONTAL TRAYS, 10 MINUTE HALON SOAK, TOTAL MASS OF DONOR TRAY 106.0 o
i w
105.5
=
=
0 1
K l
2 4
l 105.0 I
u
!?
e 0
104.5 o
z i
en
=
o i
3 2
104.0
=
t-
, a 1
%3$
8 k
I o
103.5 z
t o
e
~
2 d
103.0 E
E o
Z m
K
= -
102.5 3
m E
102.0 101.5 101.0 0
5 10 15 20 25 30 35 40 45 50 55 60 TIME IN MINUTES
-l TEST +59,lEEE-383 CABLE, HORIZONTAL TRAYS, NO HALON SOAK TOTAL MASS OF DONOR TRAY 106.0 i
105.5
~
-- r x,,
lll 105.0 E.'
104.5 104.0 3,e 103.5 O
O g
E E1 103.0 i
4 h
102.5 N
8 3
102.0 m
n:
.E E
101.5 oo a
101.0 a
m 100.5 O"
100.0 90.5 99.0 0
5 10 15 20 25 30 35 40 45 50 55 60 TIME IN MINUTES l
~
l
W 3.
No flammable concentrations of unburned hydrocarbons were pyrolyzed during the i
Halon soak time in any of the tests.
4.
A time limit on the Halon's ability to permanently extinguish a cable tray fire may have emerged.
While a 10-minute interval of Halon soak was enough to extinguish a fire in a horizontally oriented tray filled with qualified cable, a 4-minute interval was inadequate for this task.
t 5.
As mentioned above, the Halon permanently l
extinguished a fire after only a 10-minute l
soak time, whereas the same time limit on l
simple oxygen deprivation was insufficient to E
keep the flame from returning upon ventilation.
6.
While a 4-minute soak time was not enough to L
prevent a rekindling in a horizontally oriented tray filled with qualified cable, it was enough to prevent reignition in a vertically oriented tray filled with the same cable.
From this, the conclusion is that Halon more effectively quenches fires in l
vertically oriented trays than in those horizontally oriented.
II.S.3 Water Sprinkler Tests (NFPA 13)
A' series of tests was conducted to determine the effectiveness of overhead sprinklers in suppressing cable tray fires.
The original intention was to duplicate the Halon test series in order to get a direct comparison between Halon suppression'and water sprinkler suppression.
Although no final report on the water tests has been issued as yet, the results are briefly summarized here.
Table VIII lists the tests performed and the l
results.
L Two pendent-type, open-head sprinklers with standard orifices of 1/2 in. (1.3 cm) diameter were used.
The sprinklers were i
12.5 ft high (3.8 m), were offset from the cable trays and i
were separated by 12 ft (3.7 m). The water system was designed l.
.to produce a pressure of 35 psig (2.4 x 105 Pa) at each open l-head.
A total flow rate of 71 gal per minute (4.5 1 p?r second) was obtained.
The system was activated manually.
The
- 4 f
m_
L