ML20236C049
| ML20236C049 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 03/01/1989 |
| From: | William Cahill TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TXX-89099, NUDOCS 8903210461 | |
| Download: ML20236C049 (12) | |
Text
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-Log 0..TXX-89099-File ~#
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L 7UELECTRIC Ref; # 10CFR50.34(1).
' w. 3, c.hm March 1, 1989
' Executive Vice Presidmt
' l U. S. Nuclear Regulatory' Commission Attn: Document Control Desk Washington, D. C.
20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 ADVANCE FSAR CHANGE Gentlemen:
.?
Attached ~isfan advance copy of a future FSAR change consisting of marked up
.FSAR pages.
These changes provide an update to the FSAR description of toxic chemicals at CPSES. The service water and circulating water chlorination.
system and-other'significant amounts of chlorine stored onsite will be
. removed. CPSES will use an alternate biocide ~such as Sodium Hypochlorite/ Sodium Bromide in the service water and circulating water systems.
Fut_ure FSAR amendments'to appropriate portions of the FSAR will
~
' describe this change in biocide.
TV Electric will perform an evaluation in accordance with Regulatory Guide 1.78 of other toxic chemicals-at CPSES.
The removal of the surveillance requirements of the control room air intake chlorine monitors.is currently being reviewed by the NRC staff as part of the CPSES: Technical Specifications.
'These. changes will be provided in'a future FSAR amendment.
Sincerely, A-William J. Cahill, Jr.
RSB/smp i
Attachment c - Mr. R. D. Martin, Region IV Resident Inspectors, CPSES (3)
{
Ms. Melinda Malloy, OSP 0
8M iEIA SEhe gg7
)) k 400 North Olive Street LB81 Dallas, Texas 75201
{
JAttachment to TXX-89099 tia rche l,1989 CPSES/FSAR iPage 1 of.11 Discussion t
lQ421.19 This regulatory guide is not applicable to CPSES design and l8 construction activities.
The quality assurance methods for l72 operations phase activities will comply with applicable guidance l
contained in Revision 1 (4/76) of this regulatory guide.
The l
application of the requirements of ANSI N45.2'.5 -1974, as endorsed by l8 this regulatory guide, will be in accordance with the guidance l
provided in ANSI N18.7 - 1976.
l
~ Also refer to Section 17.2 l8 Regulatory Guide 1.95 f
1 Protection of Nuclear Power Plant Control Room Opers rs Against an Accidental Chlorine Release Discussion l0312.27 The CPSES design complies with the intent of Revision 1 (1/77) of this l 55 regulatoryguideasdescribedinSection/2.2 5.1 cad 0.4.
^ p!cnt l64 l
x
-+pec-Vic cncly;i; hc; been perforr;;d in lieu of the iscicted -eir--
l exchange rate speci' icd ' T2le i cf thi; regulctory guidc.
(Scc l
l Section 5.4.2.3) l Regulatory Guide 1.96 i
Design of Main Steam Isolation Valve Leakage Control Systems for Boiling Water Reactor Nuclear Power Plants Discussion
)
This regulatory guide is not applicable to the CPSES.
l l
1A(B)-55 Amendment 72 July 1, 1988 j
l
Attachm,ent to. TXX-89099 l
March 1, 1989 1
P'a ge - 2 o f 11 CPSES/FSAR
~
t effects on the plant.
The gas wells in the site vicinity, described in Section 2.5.1, could also be a source of flammable vapor clouds and were evaluated for l
their potential effects on the plant.
Since exploration in the area j
is still active, a hypothetical gas well was postulated using data j
available from the Texas Railroad Commission.
A discussion of this hypothetical wall is provided in Section 2.5.1.
2.2.3.1.3 Toxic Chemicals Inscr4 A --,.
Th; :aly t=ic chai=1 in th: Jicinity Of CPSES i: th th b rine ;;;-
- t:r:d :=it: f:r pu nt u::.
Rupter: Of : g:: cylinder ';::: c'/:lu:ted f;r it; p;t ntici off;;t: :n th; phat.
2.2.3.1.4 Fires The only non-plant-related source of fire in the vicinity of CPSES is the crude oil pipeline. The rupture of this pipeline was evaluated for its potential effect on the plant.
2.2.3.1.5 Collision with Intake Structure The Service Water Intake Structure is located on the Safe Shutdown Impoundment (see Figure 1.2-1), which is not open to public transportation. Therefore, a significant collision with this structure is not considered a credible event.
I 2.2.3.1.6 Liquid Spills The only source of liquid spills in the vicinity of CPSES is the crude oil pipeline which was evaluated for its potential effect on the plant.
j 1
I November 20, 1987 2.2-6 I
- 7_
- -Attachment'to TXX-89099 F.
March.1, 1989'.
Page 3 of 111 l
INSE37_Ai 2.2.'3.1.3-Toxic Chemicals Toxic chemicals which'.are stored and used onsite at CPSES!are evaluated in accordance with the criteria and guidance of Regulatory Guide 1.78'and NUREG 0570.-
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- Attachment to TXX-89099 d
LMarch.1,'fl989 if Page 4;of.11-CPSES/FSAR-4 2.2.3.2-Effects'of Desian Basis Events 1
The design basis events. identified above are:
1 1
J 1..
. Gas Pipeline and Gas Well Accidents
-2.
Accidental Release of Chkdr.; roxic; the,de.nl3 i
3.
. Crude Oil Pipeline Rupture Each of these is evaluated below.
2.2.3.2.1 Gas Pipeline and Gas Well Accidents I
Potential accidents involving the release of natu< al gas from existing pipelines and postulated wells described in Section 2.2.2 do not pose j
a hazard to the plant. As shown below, in the event of an accident the concentration of gas at all plant air intakes is well below the !..
lower flammability limit. Also detonation of an unconfined natural gas-air mixt' re is not considered to be a credible event (1,2,3,4].
u Each of-the existing pipelines and a potential gas well were analyzed to determine the most limiting potential accident condition; the results of this analysis indicated that the most limiting release of natural gas would involve a break.in the 36-inch Lo-Vaca natural gas pipeline.
The analysis of this accident was performed using the following conservative assumptions:
1.
A large break in the pipeline occurs at the point of nearest approach to the plant (12,250 feet to air intake structure).
I 2.
Gas is released by a constant enthalpy process yielding a gas temperature for dispersion calculations of 400F (for a 600F initial gas temperature) due to the Joule-Thompson effect.
3.
The flowrates out of the break is the maximum steady flow for single-ended break (572 m3 sec) and a double-ended break (1144
/
m3 sec).
/
2 t.
2.2-7 November 20, 1987 l
L--
March.1, 1989
' Attachment-to TXX-89099
'Page :5 of 11 CPSES/FSAR cloud (,4.95 percent volume concentration) is 746 feet for the double-ended break (1144 m3 sec) and 652 feet for the single-ended break
/
(572 m3 sec) with a 1 m/see wind speed.
Parametric studies with i
/
various flowrates showed that even under worst case conditions occurring when~ the gas flow was 600 m3 sec, the vertical distance l
/
l was 650 feet. Similar studies with various wind speeds, showed that the minimum clearance between the air intake and the lower flammability limit of the natural cloud was greater than the 650 feet obtained with the 1 m/sec wind speed.
1 i
l Similar analysis of the Lone Star 6-inch pipeline located 4,235 feet I
from the plant intake structure showed that the distance from the air intake to the lower flammability of the natural gas cloud is 3,855 feet. An analysis of a postulated gas well located 2,250 feet from the nearest plant structure showed that the distance from the structure to the lower flammability limit of the natural gas cloud is 1,050 feet.
l 2.2.3.2.2 Accidental Release of Chkrix'E a. Chem lvd3 Incr e t G -*
q orine gas cylinders are stored in chlorination buildings which locat near the Circulating Water and Service Water intake structure. There are 24 chlorine gas cylinders (one-ton-acity each) in the L ulating Water Chlorination Buildhig d six in the l
Service Water Chlo ation Building.
Under nor conditions, the leakage from the storag linders will be consequential. However, as a safety measure, leak de ctors an asks are provided in the chlorine storage and injection a Analyses were performed lizing the app ch outlined in NRC Regulatory Guide 1.
" Protection of Nuclear er Plant Control Room Operators agai an Accidental Chlorine Release."
52 lThree mospheric stability classes are analyzed: very unsta e l
tegory A) as might possibly occur in clear calm air immediate November 20, 1987 2.2-10
l Attachment to TXX-89099-
' March'1, 1989
- Page 6 of 11 INSERT 8:
I A study has been performed to evaluate the potential for chlorine releases from offsite chlorine storage and transportation affecting control room habitability. 'This study revealed no chlorine storage locations or frequent chlorine transportation within a 5 mile radius of CPSES in quantities that are larse enough to require evaluation under the criteria of Regulatory Guide 1.78.
Therefore, potential accidents involving the release of chlorine from
)
offsite storage locations and transportation routes do not pose a significant i
hazard to control room habitability.
1 i
The circulating cooling water and service water systems will be chemically l
treated for control of biololgical growth with solutions of sodium hypochlorite and sodium bromide. The diluted, sodium hypochlorite and sodium bromide solutions will not present a threat to control room habitability. No liquified chlorine will be stored within the site boundary in containters I
exceeding 150 lbs capacity.
The only liquified chlorine that will be stored within the 3rotected area will be in small quantities of 20 lbs or less to be used for la) oratory purposes.
Other toxic chemicals which are stored and used onsite at CPSES are evaluated for potential impact of their release upon control room habitability in accordance with the criteria and guidance of Regulatory Guide 1.78 and NUREG 0570.
Toxic chemicals which are determined to be hazardous to control room habitability are controlled and detection instrumentation is provided, as apropriate.
l l
Attachment to TXX-89099 March -l,.1989-Page 7 of 11 CPSES/FSAR ollowing a tornado; neutral (Category D) as might occur during rai g l 52 or cloudy weather immediately following a tornado; very stable l
(Cat ory F) as specified for consideration.in R.G. 1.78.
Wors l
case w d speeds of.one-(1) meter per second are used for Cat oriesAl and F an two-(2) meters per second for Category D.
l Chlorine rel ases from both chlorination buildings were nalyzed.
Although the S rvice Water Chlorination Building is located closer, the Control Room air intake additional dispersion due to structural obstacles causes r leases from this building to be/the less severe case.
The results c tained herein are those computed for an accidental release of lorinefromtheCirculdingWaterChlorination Building.
Two types of chlorine releas were analyed.
The first is a low leakage-rate release due to de ctive7alvesorfittings.
The second is a catastrophic rupture of one f he one-ton-capacity liquid chlorine storage cylinders.
The majority of chlorine releas s are the first type involving
/
long-term release rates not ceeding on pound of chlorine per second.
1.
Chlorine Releases ue to Leak From Valve Fittings A long-term r ease with a leakage rate of ongpound per second resulting fr m a valve / fitting defect was analy2ed.
Using the l52 diffusion odel for continuous release, the maxim'um concentration l at the C ntrol Room air intake was calculated to be\\29.3 ppm.
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2.
Chlo ine Container Rupture l
the postulated accident, it is assumed that the entire s rage cylinder of chlorine was ruptured.
The dispersion of chlorin in the atmosphere and the possible effects on the functioning or Control Room personnel were evaluated.
2.2-11 November 20, 1987
_ - _=__ _ _ - - - - _ _ _ _ _ - _
Attachment lto TXX-89099
. March"1, 1989 Page 8 of 11=
CPSES/FSAR.
j q
[yhe assumptions made.in the analysis and the results obtained/
were as follows:
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52 l
a..
A catastrophic rupture of the largest sized (one-lon-or-N
-l 2,000 lb capacity) liquid chlorine container was/ assumed.
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52 l
b.
One quarter of the_ liquid in the container,(500 lb). was p
l assumed 'to flash off instantaneously and, move. toward the l
Control Ro'om air. intake (puff release)/
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/
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52 l~
The. remaining chlorine was conservatively-assumed to l
_l evaporate into the atmosphere.at,a rate of 10 lbs per l
second (plume release).
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s 66 l
c.
The horizontal distance'between the circulating water f
l chlorine cylinder storage location and the control air' l
intake was estimated t,o'be'804 ft (245 m); the difference l
in elevation was estdnated to'be 72 ft (21.95 m).
/
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Using the above,a'ssumptions, the concentrations of chlorine-65 l
neartheContr,o'1Roomairintakewahcomputed.
The maximum l
concentration was calculated to be 649. ppm due to the puff
~
l release and-293 ppm due to the plume release.
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d.
Vapor Di.spersion Models, s
p
/
Th[ vapor from instantaneous flashing (puff) and from dontinuousvaporizationorevaporation(plume)movesinthe j
/directionofthewindanddispersesbydiffusioninto.the atmosphere. The wind is assumed to be in the directions from the source of spill to the Control Room air intake, s
Amendment 66 January 15, 1988 2.2-12 m
Atta'chment to'TXX-89099L
)Pae9 I"
f CPSES/FSAR 1)
Instantaneous Puff Release Model f
s t
ex p < - I'(- + y Q
2 2
l X=
(2#)3/2 i 2 2
XI YI ZI
\\0 XI YI s/
~
l
/
r s,
<exp e -k (I
5 II f
>+ exp, -
- Hi C,I
(#ZI
/
Z
/
~
),
~
/
where
, x - Concentration (g/m)
Q - Source Strength (g) o
. cVI, ;ZI - Adjusted standard deviation of th puff concentration in the horizontal alo wind (X), horizontal crosswind (Y) an vertical cross-wind direction (Z)
/
X, Y, Z - Distance from the puff center in the X, Y, Z directions.
2.2-13 November 20, 1987
)
Attachment t.o TXX-89099 11a rch' 1, 1989 Page _10 of 11 CPSES/FSAR H = Height of source above the ground (m).
2)
Continuous Plume Release Model s
q 2
O' Y
X=
exp (-t 2# U U
Y Z c
l.
/
,-i(Z-H)2\\+,f (Z + H)2 exp c
/
2 I
q Z
./
z
,e i
/
/
l where X - Concentrat on (m)
/
N Q'
C ntinuous so e strength (g/sec)
/
oY, aZ' = Standard deviation f the plume j/
concentration in the and Z direction
/
/
respectively. (m)
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/
\\'
Y, Z = Distance from the plume center in the Y, Z j,/
direction. (m)
/
u- = Wind Speed (m/s)
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/
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l Adjustments to account for dilution factors due to structural 52 l 'ob'stacles have been made in accordance with Reference [20] for J/ puff release and with Reference [19] for the plume release.
/
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November 20, 1987 2.2-14
Attachment to TXX-89099 -
March 1,1989' Pa' ge 11 of 11 CPSES/FSAR f
In the event.of an abnormal chlorine leakage to the environment, the/
ledk.detectorslocatedinthestorageareaswillinitiateanalar/in This alarm will alert the operator to switchIhe the Control Room.
\\
Control Room ventilation system to the emergency operation m e or the emergency recirculation mode.
In addition, the chlorine d,e ectors at l46 each Control \\8oom air intake automatically switch the Control Room l
ventilation system to the isolation mode. Termination!of outside air l-is accomplished by not permitting the emergency pres'surization fans to operate during a high chlorine release signal. The' details of the ControlRoomventilationsystemarediscussedjdSection9.4.1.
3.
ChlorineconcentratidnintheContro Room l52 N
/,
Concentration of chlorine 'in theAontrol Room were calculated l52 under three different assump'ti[ns:
l a.
Control Room Isolat on (as described in Section 9.4.1),
j52
/
b.
Control Room not isolated, and l52
/
c.
Control R m not isolated with tornado vent paths open l52 (post-t rnado conditions).
l The peakA hlorine concentration did not exceed 15 ppm for a and l52 b, abo /e. The peak concentration for c. was 26.3 ppm; however, l
the concentration did not exceed 15 ppm for a time greater than l
ty minutes after the tornado vents open.
Therefore, there is l
sufficient time for the operators to put a self-contained l
breathing apparatus into operation in accordance with Reference l
[13].
sl l
2.2.3.2.3 011 Pipeline Accidents
~
As indicated in Table 2.2-2 and as shown in Figures 2.1-2b and 2.5.1-l10 l
17, the West Texas Gulf crude oil pipeline runs, at its closest l
{
1 approach, approximately 4000 feet from the CPSES.
Considering the l
I November 20, 1987 2.2-15 l