ML20079J051
| ML20079J051 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 12/17/1982 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20079J044 | List: |
| References | |
| NUDOCS 8212280088 | |
| Download: ML20079J051 (16) | |
Text
_ _ _ _ _ ____
i ENCLOSURE 1 PROPOSED CHANGES TO TECHNICAL SPECIFICATIONS BROWNS FERRY NUCLEAR PLANT (50-259, -260, -296)
TVA BFNP TS 182 i
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i PDR ADOCK 05000259 P_
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e I
PROPOSED UNIT 1 SPECIFICATIONS
)ll S
.m m
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r
. r t
t r
ti.
h H.
H.
a s
s a
a h
y y
h s
s c
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R c
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l l
g s
s n
l d
l l
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g g
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e a i n o i ro n n n n tr w a r w or i.i i.i i
e.
t ot tnt tnt t nt t
ie iton e e n e ln tot tot tct an aere ti tati l
n o l
fo e e e e e e
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sns.
sns.sns.
na n a c z c
g r
f r
f r
f il iren s
.e s ne p u pf p u pf p u pf o
oRr n
rrr n
ir itio itioitio s
gt w ooe w l e r
r r
r r r
- a. I n c r. u oStoh oSe*
tltt tltttlt-u u,li,h r
t u
l i
iaoe d T cl p dTup
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,i,h I
tn tRf 2Ee o i S e o.
mwss awasawas ei e
r e rge rr f
f f
f f
f
+e v
re nt re t
cscl csclcscl r
l r
l r
l sL sf c
ont o oteia ctse s
mtmi 0e0i0e0i e
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s pm p
a a
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ia r
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vn vl ac e p
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)
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6.
Channel shared by RPS and Primary Containment & Reactor Vessel Isolation Control System. A channel failure may be a channel failure in each system.
7 A train is considered a trip system.
8.
Two out of three SGTS trains required. A failure of more than one will require actions A and F.
9.
There is only one trip system with auto transfer on two power sources.
10.
Refer to Table 3 7. A and its notes for a listing of Isolation Valve Groups and their initiating signals.
11.
A channel may be placed in an inoperable status for up to four hours for required survei3 lance / maintenance without placing the trip system in the tripped condition provided at least one OPERABLE channel in the same trip system is monitoring that parameter.
12.
A channel contains four sensors, all of which must be operable for the channel to be operable.
13 In the event that normal ventilation is unavailable in the main steam line tunnel, the high temperature channels may be bypassed for a period of not to exceed four hours. During periods when normal ventilation is not available, such'as during the performance of secondary containment leak rate tests, the control room indicators of the affected space temperatures shall be monitored for indications of small steam leaks. In the event of rapid increases in temperature (indicative of steam line baeak), the operator shall promptly close the main steam line isolation valves.
61 l
and tripa th) recirculstion purp]. The low-reactor water level instrumentation that is set to trip when reactor
~
water level is 17.7" (378" above vessel ~ zero) above the top of the active fuel (Table 3.2.B) initiates the LPCI, Core Spray Pumps, contributes to ADS initiation and starts the diesel generators. These trip setting levels were chosen to be high enough to prevent spurious actuation but low enough to initiate CSCS operation so that post accident cooling can be accomplished and the guidelines of 10 CFR 100 will not be violated.
For large breaks up to the complete circumferential break of a 28-inch recirculation line and with the trip setting given above, CSCS initiation is initiated in time to meet the above criteria.
The high drywell pressure instrumentation is a diverse signal to the water level instrumentation and in addition to initiating CSCS, it causes isolation of Groups 2 and 8 isolation valves. For the breaks discussed above, this instrumentation will initiate CSCS operation at about the same time as the low water level instrumentation; thus the results given above are applicable here also.
Venturis are provided in the main steam lines as a means of measuring steam flow and also limiting the loss of mass inventory from the vessel during a steam line break accident. The primary function of the instrumentation is to detect a break in the main steam line. For the worst case accident, main steam line break outside the drywell, a trip setting of 140% of rated steam flow in conjunction with the flow limiters and main steam line valve closure, limits the mass inventory loss such that fuel is not uncovered, fuel cladding temperatures remain below 1000 F and release of radioactivity to the environs is well below 10 CFR 100 guidelines. Reference Section 14.6.5 FSAR.
Temperature monitoring instrumentation -is provided in the main steam line tunnel to detect leaks in these areas. Trips are provided on this instrumentation and when exceeded, cause closure of isolation valves.
The setting of 2000F for the main steam line tunnel detector is low enough to detect leaks of the order of 15 gpm; thus, it is capable of coverine, the entire spectrum of breaks. For large breaks, the high steam flow instrumentation is a backup to the temperature instrumentation. In the event of a loss of the reactor building ventilation system, radiant heating in the vicinity of the main steam lines raises the ambient temperature above 200 degrees F.
The temperature increases can cause an unnecessary main steam line isolation and reactor scram. Permission is provided to bypass the temperature trip for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> to avoid an unnecessary plant transient and allow performance of the secondary containment leak rate test or make repairs necessary to regain normal ventilation.
High radiation monitors in the main steam line tunnel have been provided to detect gross fuel failure as in the control rod drop accident. With the established setting of 3 times normal background, and main steam line isolation valve closure, fission product release is limited so that 10 CFR 100 guidelines are not exceeded for this accident. Reference Section 14.6.2 FSAR. An alarm, with a nominal set point of 1.5 x normal full power background, is provided also.
Pressure instrumentation is provided to close the main steam isolation valves in Run Mode when the main steam line pressure drops below 825 psig.
112
h PROPOSED UNIT 2 SPECIFICATIONS
i' jll lI m
m e
e t
t r
t.
r
. r H.
H.
a s
s a
a i.
h h
y y
h s
s c
R c
R c
R d
l l
s s
n l
d l
l
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g g
g g g n n
n n n.i e
e a i n o i ro n.i i.i i
t.
tr w a r w or i
an aere t
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- e e e e ti tati l
n o l
fo e e
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sns. sns.sns na n a c
s c
g r
f r
f r
t il iren s
.e s ne p u pf p u pf p u pf o
oRr n
rrr n
ir itio itioitio s
gt w ooe w le r
r r
r r r
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u,l r
t a
l i
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tn tRf 2Se o 2Seo sw.s mwmsnwms ei e
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f i
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sL sf ee v re nt re -
cocl csclcscl l
e l
r l
ont o oteis etwe
- r. M w 0w0i0e3i i
t atl a
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pm h
th t
k ia t r*
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r re ra l tlc ltic 3 a0 2a0 0a0 a
tt tt sr 5
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S tuo 2
cnsel cnrl h
r n
r h
r sIIC w we v wew we pIIrC e
e e9 nt p
olot elctcl ot u
lal a lalal al a R
vn v1 ac e oi ooea m u..
eoee soeeeoee O
AM AIC?
J 1 ab c 1 a r, c ScSh IcbhBcBh N
ba tsl c a IT A
1 1
2 1
2 T
2 1
1 1
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F F
T l
dr dr dr S
i t
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a a
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N o
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H(
H(
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T c
m m
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f f
m I
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l l
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c c
0c 0 c 0c N
o s
s 2
2 0
n n
n 0
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w w
50 50 50 L
t o
o 0
0 0
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s2 s2 s2 r
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3U e
B S
r r
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t t
t as as as LR l
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v h
h He He He T C' s
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r 1
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r r
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6 5
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Y lu lan la iVt lVt l
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a e a en en en n e nlae nl g n gi ngi ni ni ni A
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hr hdR hdRn nT hT hT R
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)
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C P tfllIl ii
6.
Channel shared by RPS and Primary Containment & Reactor Vessel Isolation Control System. A channel failure may be a channel failure in each system.
7 A train is considered a trip system.
8.
Two out of three SGTS trains required. A failure of more than one will require actions A and F.
9.
There is only one trip system with auto transfer on two power sources.
I 10.
Refer to Table 3 7. A and its notes for a listing of Isolation Valve i
l Groups and their initiating signals.
)
l 1
11.
A channel may be placed in an inoperable status for up to four hours for required surveillance / maintenance without placing the trip system in the tripped condition provided at least one OPERABLE channel in the same trip system is monitoring that parameter.
12.
A channel contains four sensors, all of which must be operable for the channel to be operable.
l 13 In the event that ncrmal ventilation is unavailable in the main steam line tunnel, the high temperature channels may be bypassed for a period of not to exceed four hours. During periods when normal ventilation is not available, such as during the performance of secondary containment leak rate tests, the control room indicators of the affected space temperatures shall be monitored for indications of small steam leaks. In the event of rapid increases in temperature (indicative of steam line break), the operator shall promptly close the main steam line isolation valves.
61
32 BASES and trips tha rceirculction pu;p]. The low reactor water level instrumentation that is set to trip when reactor m,
water level is 17.7" (378" above vessel zero) above the top of the active fuel (Table 3.2.B) initiates the LPCI, Core Spray Pumps, contributes to ADS initiation and starts the diesel generators. These trip setting l
l levels were chosen to be high enough to prevent spurious actuation but l
low enough to initiate CSCS operation so that post accident cooling can be accomplished and the guidelines of 10 CFR 100 will not be violated.
For large breaks up to the complete circumferential break of a 28-inch i
recirculation line and with the trip setting given above, CSCS initiation i
is initiated in time to meet the above criteria.
The high drywell pressure instrumentation is a diverse signal to the water level instrumentation and in addition to initiating CSCS, it causes isolation of Groops 2 and 8 isolation valves. For the breaks discussed above, this instrumentation will initiate CSCS operation at about the I
same tima as the low water level instrumentation; thus the results given above are applicable here also.
Venturis are provided in the main steam lines as a means of measuring steam flow and also limiting the loss of mass inventory from the vessel during a steam line break accident. The primary function of the instrumentation is to detect a break in the main steam line. For the worst case accident, main steam line break outside the drywell, a trip setting of 140% of rated steam flow in conjunction with the flow limiters and main steam line valve closure, limits the mass inventory loss such that fuel is not uncovered, fuel cladding temperatures remain below 10000? and release of radioactivity to the environs is well below 10 CFh 100 guidelines. Reference Section 14.6.5 FSAR.
Temperature monitoring instrumentation is provided in the main steam line tunnel to detect leaks in these areas. Trips are provided on this instrumentation and when exceeded, cause closure of isolation valves.
The setting of 200 F for the main steam line tunnel detector is low enough to detect leaks of the order of 15 gpm; thus, it is capable of covering the entire spectrum of breaks. For large breaks, the high steam flow instrumentation is a backup to the temperature instrumentation. In the event of a loss of the reactor building ventilation system, radiant heating in the vicinity of the main steam lines raises the ambient temperature above 200 degrees F.
The temperature increases can cause an unnecessary main steam line isolation and reactor ceram. Permission is provided to bypass the temperature trip for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> to avoid an unnecessary plant transient and allow performance of the secondary containment leak rate test or make repairs necessary to regain normal ventilation, liigh radiation monitors in the main steam line tunnel have been provided to detect gross fuel failure as in the control rod drop accident. With the established setting of 3 times normal background, and main steam line isolation valve closure, fission product release is limited so that 10 CFR 100 guidelines are not exceeded for this accident. Reference Section 14.6.2 FSAR. An alarm, with a nominal set point of 1.5 X normal full power background, is provided also.
Pressure instrumentation is provided to close the main steam isolation valves in Run Mode when the main steam line pressure drops below 825 psig.
112
e PROPOSED UNIT 3 SPECIFICATIONS
.l
- jjII; b
t n
n n
t n
n i
i i
n e
a a
a i
g m he M
g m
M M
M e
es a
n n i i l
s i i s
s s
s n n tv e d a
sa e
e d a
e e
e e.
t h
l t
ev t
h l
t t
t t
t i n t
a t
i n a
a a
an u o an i
u o i
i i
io s
B C
lo t
s B c t
t t
ti e
oi i
e i
i i
it o r y
st n
o r y
n n
n na d o r ic in c o r in in in il t
a u
o t
a o
o o
o g c m S gs.
gi g c m S
gi gi gi gs n a i T n m nt n a i T nt nt nt nI i e r G ige ia i e r G ia ia ia i t
R P
S tnt tl t R P
S tl tl tl te to to to tn t
tis to t
e snsns ely es e snsns es es es ei s eoeoe sos sI s eoeoe sI sI sI sL titit k
p:atata pcR pe p:atata pe pe pe pm s
titit o
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rntltlt rnR ri rntltlt ri ri ri re m
tiioioi tw tL tiioioi tL tL tL ttS wnsnsn R
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ll Bfa b c Aso BS Afa b c AS BS AS AM IT A
1 1
1 1
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B B
a N
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c B
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e 5
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mr mr mr-mr-mau me ml mte uo uo uo3 uD4 uRT ur uP uST rt rt rt -
r 6
r rP r
r tc tc tcS th-the t
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3 There are four channels per steam line of which two must be operable.
4.
Only required in Run Mode (interlocked with Mode Switch).
5.
Not required in Run Mode (bypassed by Mode Switch).
6.
Channel shared by RPS and Primary Containment & Reactor Vessel Isolation Control System. A channel failure may be a channel failure in each system.
7.
A train is considered a trip system.
8.
Two out of three SGTS trains required. A failure of more than one will require actions A and F.
9 There is only one trip system with auto transfer on two power sources.
10.
Refer to Table 3.7. A and its notes for a listing of Isolation Valve l
Groups and their initiating signals.
11.
A channel may be placed in an inoperable status for up to four hours for required surveillance / maintenance without placing the trip system in the tripped condition provided at least one OPERABLE channel in the same trip system is monitoring that parameter.
12.
A channel contains four sensors, all of which must be operable for the channel to be operable.
13 In the event that normal ventilation is unavailable in the main steam line tunnel, the high temperature channels may be bypassed for a period of not to exceed four hours. During periods when normal ventilation is not available, such as during the performance of secondary containment leak rate tests, the control room indicators of the affected space temperatures shall be monitored for indications of small steam leaks. In the event of rapid increases in temperature (indicative of steam line break), the operator shall promptly close the main steam line isolation valves.
63
~
32 BASES and HPCI,and trips the recirculation pumps. The low reactor water level instrumentation that is set to trip when reactor water level is 17.7" (378" above vessel zero) nbove the top of the active fuel (Table 3 2.B) initiates the LPCI, Core Spray Pumps, contributes tn ADS initiation and starts the diesel generators. These trip setting levels were chosen to be high enough to prevent spurious actuation but low enough to initiate CSCS operation so that post accident cooling can be accomplished and the guidelines of 10 CFR 100 will not be violated.
For large breaks up to the complete circumferential break of a 28-inch recirculation line and with the trip setting given above, CSCS initiation is initiated in time to meet the above criteria.
The high drywell pressure instrumentation is a diverse signal to the water level instrumentation and in addition to initiating CSCS, it causes isolation of Groups 2 and 8 isolation valves. For the breaks discussed above, this instrumentation will initiate CSCS operation at about the same time as the low water level instrumentation; thus the results given above are applicable here also.
Venturis are provided in the main steam lines as a means of measuring steam flow and also limiting the loss of mass inventory from the vessel during a steam line break accident. The primary function of the instrumentation is to detect a break in the main steam line. For the worst case accident, main steam line break outside the drywell, a trip setting of 140% of rated steam flow in conjunction with the flow limiters and main steam line valve closure, limits the mass inventory loss such that fuel is not uncovered, fuel cladding temperatures remain below 10000F and release of radioactivity to the environs is well below 10 CFR 100 guidelines. Reference Section 14.6.5 FSAR.
Temperature monitoring instrumentation is provided in the main steam line tunnel to detect leaks in these areas. Trips are provided on this instrumentation and when exceeded, cause closure of isolation valves.
The setting of 200 F for the main steam line tunnel detector is low enough to detect leaks of the order of 15 gpm; thus, it is capable of coverinc, the entire spectrum of breaks. For large breaks, the high steam flow instrumentation is a backup to the temperature instrumentation. In the event of a loss of the reactor building ventilation system, radiant heating in the vicinity of the main steam lines raises the ambient temperature above 200 degrees F.
The temperature increases can cause an unnecessary main steam line isolation and reactor scram. Permission is provided to bypass the temperature trip for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> to avoid an unnecessary plant transient and allow performance of the secondary containment leak rate test or make repairs necessary to regain normal ventilation.
High radiation monitors in the main steam line tunnel have been provided to detect gross fuel failure as in the control rod drop accident. With the established setting of 3 times normal background, and main steam line isolation valve closure, fission product release is limited so that 10 CFR 100 guidelines are not exceeded for this accident. Reference Section 14.6.2 FSAR. An alarm, with a nominal set point of 1.5 X normal full power background, is provided also.
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DESCRIPTION AND JUSTIFICATION (TVA'BF/P TS 182)'
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These proposed specifications allow the temporary hypassing, up to
four hours, of the temperature switches in the mainsteam line tunnel. This is done by addition of note 13 to Table 3 2.A.
The pages affected are:
ubits 1 and 2 - 56, 61, and 112 unit 3 57, 63, and 109
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A SAFETY ANALYSIS, MSL HICll TEMPERATURE BYPASS Units 1, 2, and 3 Purpose To prevent spurious steam line isolations due to high tunnel temperature when the normal ventilation system is not available. Allow performance of the secondary containment leak rate test at minimal risk to operating units.
Justification As a result of recent problems with the secondary leak rate test at Browns Ferry Nuclear Plant, we have determined that the secondary containc. ant leak rate test is best performed if the inter, rated building inleakage can be measured. This involves testing the refueling zone and the three reactor zones simultaneously rather than attempting to test individual zones. To perform this test, normal ventilation in all the zones must be secured.
With 'anits in operation, 'he local temperature in the main steam line tunnel increases rapidly (uithin 30 minutes during warm weather) to the I
space temperature setpoint of 2000F. This will cause a full isolation of the main steam line isolation valves, with resultant reactor trip, loss of the feedwater pumps, and lifting of safety / relief valves. HPCI and/or RCIC would then be required to maintain core cooling. This would apply to however many units are operating (normally two since the secondary test is performed before fuel handling for refueling outages). The surveillance frequency is approximately every six months (3 units on 18-month cycles).
Loss of normal ventilation is a mild and infrequent event. However, without the capability to temporarily bypass the main steam line tunnel high temperature trip switches (allowing time to reestablish normal ventilation flow), it poses unnecessary challenges to the reactor safety systems.
The economic cost associated with requiring two units (asr,umins o
. nit is in a refueling outage) to be shutdown due to normal ventilation ts.6g lost or secured for tests amounts to approximately $2 million since a shutdown and restart would consume approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
Safety Analysis The main steam line space temperature detection system is designed to detect small pipe breaks in the steam tunnels and to initiate isolation to prevent an uncontrolled release of primary coolant and radioactive materials (reference PSAR section 7 3). The offsite dose calculations for this event are easily bounded by the design basis case for a complete main steam line break. The offsite dose for the design bases case in itself is very low (reference FSAR section 14.6.5).
In support of the Ilrowns Ferry full scale probabilintic rink assessment (Pila), we have determinod that the prohahtlity of any break in the main steam line piping betwoon the outboard Hil!Vn and the turbino ntop valves in 2.42X10-4/ year. The probability of failure of the piping and the corresponding need for the high temperature switches during the four-hour maintenar)ce and surveillance period is therefore calculated to be 1.1X10-7 The very low risk associated with the bypassed temperature switches is reduced further by the proposed administrative requirements to monitor other available temperature indicators in the affected area. In addition, the logic for the steam line low pressure and high flow isolation functions is unaffected by the proposed change and remains available in the event of a main steam line break.
The proposed change improves reactor safety by allowing sufficient time to I
reestablish normal ventilation after making necessary repairs or for completion of surveillance testing of secondary containment leakage thus avoiding unnecessary challenges to safety systems.
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