ML20077F097
| ML20077F097 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 12/07/1994 |
| From: | TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | |
| Shared Package | |
| ML20077F091 | List: |
| References | |
| NUDOCS 9412130267 | |
| Download: ML20077F097 (35) | |
Text
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i ATTACHMENT 3 TO TXX 94326 AFFECTED TECHNICAL SPECIFICATION PAGES (NUREG - 1468)
" Technical Specifications. CPSES Units 1 and 2" l
[Pages 3/4 7 8, B 3/4 7 3, Insert A Page (1), Insert B Pages (1) and (2),
Insert A Pages (2) through (6)]
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l 9412130267 DR 941207 ADOCK 05000445 PDR
PLANT SYSTEMS MAIN STEAM LINE ISOLATION VALVES LIMITING CofEITION FOR OPERATION
, Feue. Msiv, 3.7.1.5 [Each main steam line isolation valve (MSIV)l shall be OPERA 8LE.
APPLICABILITY: MODES 1, 2, and 3 ACTION:
MODE 1:
STARTOP dihin %e next 6 hurs ,
I ,
6 i With one MSIV 1 1 operable but open, POWER OPERATION may con nue provided the inoperable valve is restored to OPERA 8LE status within <[fhours; _o.
otherwise be irtlHOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in 40T SHUT 00WNJ~
(within the followina 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />sJ MODES 2 and 3*: uWn 8 hm l or mare. I closed once.es anel varme per 7 da3s ssnt With one MSIV!1noperable, su g(equent operation in l MODE 2 or 3 may proceed '
provided the nsolation valvelistanintainedrclose4 Otherwise, be in HOT ,
STAN08Y 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. within the next 6 hou'rs and in H0T SHUTDOWN within the following l v,
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SURVEILLANCE REQUIREMENTS '
4.7.1.5 Each MSlV shall be demonstrated OPERA 8LE by verifying I (within 5 seconan7when tested pursuant to Specification 4.0.5.
The provisions of Specification 4.0.4 are not applicable for entry into MODE 3.
Separde, 4cr %ch MStV, entr3 46e3 ige y;% gg.%Q (3 gy
)
COMANCHE PEAK - UNITS 1 AND 2 3/4 7-8 l
. PLANT SYSTEMS l
BASES' 3/4.7.1.4 SPECIFIC ACTIVITY the resultant offsite radiation dose will be limited to a small fr 10 CFR 100 dose guideline values in the event of a steam line rupture. This dose also includes the effects of a coincident 1 gpa primary-to-secondary tube leak in the steam generator of the affected steam line.
consistent with the assumptions used in the safety analyses. These values are l
lea A >3/4.7.1.5 MAIN STEAM LINE ISOLATION VALVES more than one ERASILITY of the main steam line isolation valves ensures t rupture. This restricenerator required will blowto:
down in the event of 1
ine effects of the Reactor Coolant raa1 6(..)ssociated si e positive reactivity (2) limit the pressure rise w na with the blowdown, and rupture occurs wit nment. The OPERA 81LITY he event the steam line valves e closure times of the Surveillance Requiremenin steam isolation e assumptions used in the safety analyses. onsisteht N
3/4.7.1.6 MAIN FEEDWATER ISOLATION VALVES The feedwater isolation valves the feedwater isolation bypass valves, and the feedwater preheater bypass v,alves are designed to close on a Feedwater Isolation Signal to 1) limit the cooldown following a safety injection / reactor trip, and 2) limit the mass addition to the containment on a steamline break I
insideincontainment, result over feeding of and 3) limit a steam the severity of feedwater malfunctions which generator. The allowed outage times and safety functions of the valves. required actions are consistent with nomal plant 3/4.7.1.7 STEAN GENERATOR ATMDSPHERIC RELIEF VALVES l
i The OPERA 8ILITY of the steam generator atmospheric relief valves (ARVs) ensures that reactor decay heat can be dissipated to the atmosphere in the event of a steam generator tube rupture and loss of offsite power and that the Reactor Coolant System can be cooled down for Residual Heat Removal System operation.
Two ARVs are required to cool the Reactor Coolant System in a time frame compatible with prevention of overfill of the faulted steam generator. All four ARVs are required to be OPERA 8LE to allow for not being able to use the ARV on the faulted ARVs. steam generator and an active failure of o,ne of the remaining three 3/4.7.2 STEAM GENERATOR PRESSURE / TEMPERATURE LIMITATION The limitation on steam generator pressure and temperature ensures that the pressure-induced stresses in the steam generators do not exceed the maximum allowable fracture toughness stress limits.
The limitations of 70*F and 200 psig are based on a steam generator RT,,, of 60*F and are sufficient to prevent brittle fracture.
COMANCHE PEAK - UNITS I AND 2 8 3/4 7-3
CL
BACXGROUND The MSIVs isolate steam flow from the secondary side of the steam generators following a high energy line break (HELB).
MSIV closure terminates flow from the unaffected (intact) steam generators.
[3 &gier es volv.s (4mv.)staom generedor oMospher One MSIV is located in each main steam line outside, but close to, containment. The MSIVs are downstream from the main steam safaty valves (MSSVs) and auxiliary feedwater #
(AFW) pump turbine steam supply, to prevent MSSV isolation from the steam generators by MSIV clos,u[and re. AFW~
Closing the MSIVs isolates each steam generator,from the others, and isolates the turbine, d""'P other auxiliary steam supplies fro /teamGEa~stj}ystem, m the steam generators, and i
or ste w I;ne The MSIVs close on a main steam isolation signal generated pre.ssure nep6e, by either low steam generator pressure, igh containment l r'o+ e. -%3 h pressurb.j ine .m ys rail closea en toss of controi or A l cactuation oowerJ Ead, MSN bos an f duas Powe, Operd%n decte Col N o [ ww.k is lockeel closed Each MSIV has an MSIV bypass valve 4 [Although these bypass S fedn meMIc to r valves are normally closec, tney refreive the same emeroency.
ensure. &at Ae- closure sional as do their associated MSIVs. (g he T MSIVs may VoWes con be.
c.losecIevew 8 also be actuated manually. om4,,,lw%p,hd a
s hp.ar M9eeb w w A%wrt
%e.vc.Wes caso '
vees are. fock.a GM cAnse on loss Section (10.3] (Ref.1). y m.g ,a 3, o9 h34ecuiic.fhsel. **f* *g,+ dH 5 "h.
Inw t s APPLICABLE [ThedesignbasisoftheMSIVsisestablishedbythe SAFETY ANALYSES containment analysis for the large steam line break (SLB) inside containment, discussed in the FSAR, Section (5.2] ,
(Ref.2). It is also affected by the accident analysis of l the SLB events presented in the FSAR, Section (15.1.5]
(Ref.3). The design precludes the blowdown of more than one steam generator, assuming a single active component failure (e.g., the failure of one MSIV to close on demand).
The limiting case for the containment analysis is the SLB inside containment, with a loss of offsite power following turbine trip, and failure of the MSIV on the affected steam /
(continued) o o _ o_
DOG STSJ ~ 73. 7-f) k 0, 09/28/92) '
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h s e.r 4 6 APPLICABLE SAFETY ANALYSES:
The basis for the MSIV operability is derived from their assumed operation in the accident analyses of the breaks in the secondary system (principally, steamline break). The. design of the secondary system precludes the uncontrolled blowdown ,
of more than one steam generator, assuming a single active component failure (e.
g., the failure of one MSIV to close on demand), in addition, the MSIVs are credited in the analyses of the steam generator tube rupture accidents. ,
in the safety analyses, several different SLB events are compared against different event acceptance limits. A double-ended guillotine SLB at hot zero power is the limiting case with respect to the_ core response. The double-ended guillotine SLB outside containment upstream of the MSIV is limiting for offsite dose i consequences, although a break in this short section of piping has a very low probability. A 1.0 fta non-mechanistic break downstream of the MSIVs in the steam tunnels from at-power conditions is limiting with respect to environmental qualification in the steam tunnels. A large SLB at higher power levels is limiting l with respect to maximum containment temperature used for equipment l qualification. In the anriyses of the feedwater line break and steam generator tube ,
rupture accidents, the MSIVs are credited for steam generator isolation. A i significant failure considered for all cases is the failure of a MSIV to close. i (o.se %e w V VJ3 %dien 4 to eless, on do**mA. . >
The MSIVs ::rz: r 'y : ::fri r f:"r :dromain open during power operation '
These valves are assumed to operate under the following situations:
1
- a. A HELB (SLB or FLB) inside containment. In order to maximize the mass and energy release into containment, the analyses assumes that the MSIV on the affected steam generator fails to close. For this scenario, steam is discharged into containment from all steam generators until the remaining MSIVs close. After MSIV closure, steam is discharged into containment only from the affected steam generator and from the residual steam in the main
)
steam piping downstream of the closed MSIVs in the unaffected loops.
Closure of the MSIVs isolates the break from the unaffected steam l generators.
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- b. A break or postulated crack outside of containment does not affect the containment environment, but may affect the environment in the steam tunnels. With respect to the core response to a SLB event, the uncontrolled blowdown of more than one steam generator must be prevented to limit the potential for uncontrolled RCS cooldown and positive reactivity addition.
Assuming that the MSIV on the affected steam generator fails to close, the closure of the other MSIVs isolates the break and limits the blowdown to a single steam generator.
- d. Following a steam generator tube rupture event, closure of the MSIVs isolates the affected steam generator from'the intact steam generators. In addition to minimizing radiological releases, this enables the operator to maintain t e pressure of the steam generator with the ruptured tube below the setpoints, a necessary step toward isolating the flow through the l
rupture. p ggy
- e. The MSIVs are also utilized during other events such as a feedwater line break. These events are less limiting so far as MSIV OPERABILITY is concerned.
The MSIVs satisfy Criterion 3 of the NRC Policy Statement on Technical Specification improvements for Nuclear Power Reactors (58FR39132 of July 22, 1993).
h"44 33 % (2) 4(Q
MSIVs f B 3.7.2 APPLICABLE F generator to close. At lower powers, the steam generator SAFETY ANALYSES inventory and temperature are at their maximum, maximizing (continued) the analyzed mass and energy release to the containment. )
Due to reverse flow and failure of the MSIV to close, the additional mass and energy in the steam headers downstream from the other MSIV contribute to the total release. With the most reactive rod cluster control assembly assumed stuck in the fully withdrawn position, there is an increased possibility that the core will become critical and return to '
power. The core is ultimately shut down by the boric acid injection delivered by the Emergency Core Cooling System.
The accident analysis compares several different SLB events against different acceptance criteria. The large SLB outside containment upstream of the MSIV is limiting for offsite dose, although a break in this short section of main steam header has a very low probability. The large SLB inside containment at hot zero power is the limiting case .
for a post trip return to power. The analysis includes -
scenarios with offsite power available, and with a loss of offsite power following turbine trip. With offsite power available, the reactor coolant pumps continue to circulate ,
coolant through the steam generators, maximizing the Reactor Coolant System cooldown.- With a loss of offsite power, the '
response of mitigating systems is delayed. Significant-single failures considered include failure of an MSIV to close.
The MSIVs serve only a safety function and remain open during power operation. These valves operate under the following situations:
- a. An HELB inside containment. In order to maximize the mass and energy release into containment, the analysis assumes that the MSIV in the affected steam generator remains open. For this accident scenario, steam is discharged into containment from all steam generators until the remaining MSIVs close. After MSIV closure, steam is discharged into containment only from the affected steam generator and from the residual steam in the main steam header downstream of the closed MSIVs in the unaffected loops. Closure of the MSIVs isolates the break from the unaffected steam L generators.
(continued)
GdOG STS (Tiev. O, 09/28/9 l
- 19 'E , h h) k (8)
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..e MSIVs 8 3.7.2
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- b. Abreakoutsideofcontainmentandupstreamfromthe)
APPLICABLE !
SAFETY ANALYSES MSIVs is not a containment pressurization concern.
(continued) The uncontrolled blowdown of more than one steam generator must be prevented to limit the potential for uncontrolled RCS cooldown and positive reactivity -!
addition. Closure of the MSIVs isolates the break and limits the blowdown to a single steam generator,
)
- d. Following a steam generator tube rupture, closure of the MSIVs isolates the ruptured steam generator from the intact steam generators. In addition to ,
minimizing radiological release;, this enables the j operator to maintain the pressure of the steam- i generator with the ruptured tube below the MSSV i setpoints, a necessary step toward isolating the flow - l
_ through the rupture.
l
- e. The MSIVs are also utilized during other events such '
as a feedwater line break. This event is less limiting so far as MSIV OPERA 81LITY is concerned.
The MSIVs satisfy Criterion 3 of the NRC Pol. icy Statement. ) -
a __
LCO ThisLCOrequiresthat(>fou MSIVs in the steam lines be OPERABLE. The MSIVs are co idered OPERA 8LE when the isolation times are within limits, and they close on an isolation actuation signalpg g}Q nyned 4,3,2,{ ;
This LCO provides assurance that the MSIVs will perform their design safety function to mitigate the consequences of accidents that could result in offsite exposures comparable to the 10 CFR 100 (Ref. X) limits or the NRC staff approved licensing basis. 1 APPLICABILITY The MSIVs must be OPERABLE in MODE 1,(End in ,and 3 (xcept wnen c mm. and de-activateiri wrien there is significant mass and energy in the1CS and steam generators.
When the MSIVs are closed, they are already performing the safety function. ,
(continued)
GoG STS[ CB3.79N 6v . O,09/28/9) 1* M h ,ih (O y (O
[MSIVs L8 3.7.2 O
APPLICABILITY In MODE 4, nonnally most of_ the MSIVs are closed, and the (continued) steam generator energy is low.
In MODE 5 or 6, the steam generators do_not contain much energy because their temperature is below the boiling point of water; therefore, the MSIVs are not required for isolation of potential high energy secondary system pipe breaks in these MODES.
ACTIONS ricoE. I :
With one MSIV inoperable in M00 actio restore OPERA 8LE status within bours.nmustbetakento 5 Iepairs to t)1e MSIV ca be made with the un . hot. The [ hour
- Completion ime is reasonable, considering the ow probability of an accident occurring during this time period that would require a closure of the MSIVs.
The h hour /ompletion /ime is greater than that nornarily allowe for containment isolation valves because the MSIVs are valves that isolate a closed system penetrating containment. These valves differ from other containment ..
isolation valves in that the closed system additional means for containment isolation.provides an Hooes 2ced 2 Actio^)
1e MSIV cannot be restored to OPE LE status within l'
(. Tours, the unit must be placed in , MODE in which the L does not apply. To achieve.this spatus, the unit must be placed in MODE 2 withi 6 hcurs aneae tion LTwould be entered. Thegompletion ines are rea3onai e, based on operating experience, to reach MODE 2 and to close the MSIVs i in an orderly manner and without challenging unit systems. l (C.1 and C.2[ MODES Z MO 3 :
WS
- Gond- Han 47 s modified by a Note indicating that separate mona :1onTentry is allowed for each,MSIV.
Since the MSIVs are required to be OPERA 8LE in MODES 2 and 3, the inoperable MSIVs may either be restored to (continued) 60G STS [ CB3.7-10 (Ifev. O, 09/28/92 IwvF A , ASc (+) tr @) L l
d o
~
- ( MSIVsl .
(B 3.7.21 ACTIONS noogsz.wsg(continued)
(C.1 and C.7)
OPERABLE status or closed. When closed, the MSIVs are already in the position required by the assumptions in the safety analysis.
The hourjo letion/imeisconsistentwiththatallowed-in condition a- obsi Ac.r/W ,
For inoperable MSIVs that.cannot be restored to OPERABLE statuswithinthespecifiedgompletionfine,butareclosed, the inoperable MSIVs must be verified on'a periodic basis to be closed.- This is necessary to ensure that-the assumptions in the safety. analysis remain valid. The7daygompletion
/ime is reasonable, based on engineering judgment, in view of MSIV status indications available in the control room, and other administrative controls, to ensure that these valves are in the closed position. -
o-(0.1and0.2]
If.the MSIVs cannot be restored to OPERABLE status or are notclosedwithintheassociatedgompletion mustbeplacedinaMODEinwhichtheLC0do/ime,theunit es not. apply.
To achieve this status, the unit must be placed at least.in MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and in MODE 4 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The allowed fonpletion /imes are reasonable, based on operating experience, to reach the required unit conditions from i MODE 2 conditions in an orderly manner and without challenging unit systems.
4.~1.E.s _
yy pgQm SURVEILLANCE (SR 3.7.2.1]"- r k.CP6EsTR H :
REQUIREMENTS ,,
This SR verifies that MSIV closure time is 6s ra 41 seconds) - :
MM ,^ on an actual or simulated actuation signa 1I The MSIV l
- N closure timelis assumed in the accident and containment i analyses. This Surveillance is normally performed upon W returning the unit to operation following a refueling outage. The MSIVs should not be tested at power, since even a part stroke exercise increases the risk of a valve closure when the unit is generating power. As the MSIVs are not tested at power, they are exempt from the ASME Code, (continued) o m -
CwoG STS) di 3.7 11) dev. O,09/28/92)O
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[MSIVs LB3.7.2 1
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- 4. 7. I . 5 SURVEILLANCE REQUIREMENTS (SR 3.7.2.1}(continued) b Section XIffRefs 58 requirements during operation in MODE 1 !
r 2.
,.gm a 4o Spec $cedien 4 0.5 7 The Frequency is in accordance whh the Iftnservice Testina Progran or [18] months]. The [18; month ~ Frequency for valve co time is based on the refueling cycle. Operating experience has shown that these components usually pass the Surveillance when performed at the [18] month Frequency.
Therefore, the Frequency is acceptable from a reliahility standpoint. f This test is conducted in* MODE 3 with the unit at operating temperature and pressureddis discuused in Reference 574L-cyxercising requirementFhis SR 1 s modified by a Note that 4
4 fnarfomina the sly. allows entry into and ooeration in muut 3 orior toF This allows a delay of testing until "
1 MODE 3, to establish conditions consistent with those under which the acceptance criterion was generated.
p REFERENCES fl. FSAR, Section [10.3]. .
- 2. FSAR, Section [6.2] . Prov, ides eggen from sp..;ggq
- 3. #
FSAR, Section [15.1.5]. , ocle. [ "b 14 10 CFR 100.11.
5.
b ASME, Boiler and Pressure Vessel Code Section XI, Inservice Inspection, Article IWV-3.400.
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CWOG STS) O,09/28/92) 13.7-121 Q f, 8< On q p
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ENCLOSURE 1 TO TXX-94326 NUREG 1431 " Standard Technical Specifications, Westinghouse Plants.
-TS 3.7.2, " Main Steam Isolation Valves (MSIVs)"
[Pages 3.7-5 and 3.7 6. B 3.7-7 through B 3.7-12]
l
. MSIVs 3.7.2 3.7 PLANT SYSTEMS 3.7.2 Main Steam Isolation Valves (MSIVs)
LC0 3.7.2 [Four] MSIVs shall be OPERABLE.
APPLICABILITY: MODE 1, MODES 2 and 3 except when all MSIVs are closed and
[de-acti vated] .
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One MSIV inoperable in A.1 Restore MSIV to [8] hours MODE 1. OPERABLE status. ,
B. Required Action and B.1 Be in MODE 2. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> associated Completion Time of Condition A not met.
C. ---------NOTE--------- C.1 Close MSIV. [8] hours Separate Condition entry is allowed for AND each MSIV.
C.2 Verify MSIV is Once per closed. 7 days One or more MSIVs inoparable in MODE 2 or 3.
(continued)
WOG STS 3.7-5 Rev. 0, 09/28/92
MSIVs 3.7.2 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME D. Required Action and D.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> associated Completion Time of Condition C AND not met.
D.2 Be in MODE 4. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.7.2.1 -------------------NOTE--------------------
Only required to be performed in MODES 1 and 2.
Verify closure time of each MSIV is In accordance ,
s [4.6] seconds on an actual or simulated with the actuation signal. [ Inservice Testing Program or [18] months]
WOG STS 3.7-6 Rev. O, 09/28/92
MSIVs 1 B 3.7.2 B 3.7 ' PLANT SYSTEMS B 3.7.2 Main Steam Isolation Valves (MSIVs)
BASES BACKGROUND The MSIVs isolate steam flow from the secondary side of the !
steam generators following a high energy line break (HELB).
MSIV closure tenninates flow from the unaffected (intact) steam generators.
One MSIV is located in each main steam line outside, but close to, containment. The MSIVs are downstream from the main steam safety valves (MSSVs) and auxiliary feedwater (AFW) pump turbine steam supply, to prevent MSSV and AFW isolation from the steam generators by MSIV closure.
Closing the HSIVs isolates each steam generator from the others, and isolates the turbine, Steam Bypass System, and other auxiliary steam supplies from the steam generators.
The MSIVs close on a main steam isolation signal generated by either low steam generator pressure or high containment pressure. The HSIVs fail closed on loss of control or actuation power.
Each MSIV has an MSIV bypass valve. Although these bypass valves are normally closed, they receive the same emergency closure signal as do their associated MSIVs. The MSIVs may also be actuated manually.
A description of the MSIVs is found in the FSAR, i Section (10.3] (Ref.1).
l APPLICABLE The design basis of the MSIVs is established by the SAFETY ANALYSES containment analysis for the large steam line break (SLB) inside containment, discussed in the FSAR, Section [6.2]
(Ref.2). It is also affected by the accident analysis of the SLB events presented in the FSAR, Section [15.1.S] ,
(Ref. 3). The design precludes the blowdown of more than l one steam generator, assuming a single active component failure (e.g., the failure of one MSIV to close on demand).
The limiting case for the containment analysis is the SLB inside containment, with a loss of offsite power following turbine trip, and failure of the MSIV on the affected steam (continued)
WOG STS B 3.7-7 Rev. O, 09/28/92
MSIVs B 3.7.2 BASES APPLICABLE generator to close. At lower powers, the steam generator SAFETY ANALYSES inventory and temperature are at their maximum, maximizing (continued) the analyzed mass and energy release to the containment.
Due to reverse flow and failure of the MSIV to close, the additional mass and energy in the steam headers downstream from the other MSIV contribute to the total release. With the most reactive rod cluster control assembly assumed stuck in the fully withdrawn position, there is an increased possibility that the core will become critical and return to power. The core is ultimately shut down by the boric acid injection delivered by the Emergency Core Cooling System.
The accident analysis compares several different SLB events against different acceptance criteria. The large SLB outside containment upstream of the MSIV is limiting for offsite dose, although a break in this short section of main steam header has a very low probability. The large SLB inside containment at hot zero power is the limiting case for a post trip return to power. The analysis includes scenarios with offsite power available, and with a loss of offsite power following turbine trip. With offsite power available, the reactor coolant pumps continue to circulate coolant through the steam generators, maximizing the Reactor Coolant System cooldown. With a loss of offsite power, the response of mitigating systems is delayed. Significant single failures considered include failure of an MSIV to close.
The MSIVs serve only a safety function and remain open durfog power operation. These valves operate under the following situations:
- a. An HELB inside containment. In order to maximize the mass and energy release into containment, the analysis assumes that the MSIV in the affected steam generator remains open. For this accident scenario, steam is discharged into containment from all steam generators until the remaining MSIVs close. After MSIV closure, steam is discharged into containment only from the affected steam generator and from the residual steam in the main steam header downstream of the closed MSIVs in the unaffected loops. Closure of the HSIVs isolates the break from the unaffected steam generators.
(continued)
WOG STS B 3.7-8 Rev. O, 09/28/92
. MSIVs B 3.7.2 BASES APPLICABLE b. A break outside of containment and upstream from the SAFETY ANALYSES MSIVs is not a containment pressurization concern.
(continued) The uncontrolled blowdown of more than one steam generator must be prevented to limit the potential'for uncontrolled RCS cooldown and positive reactivity addition. Closure of the MSIVs isolates the break and limits the blowdown to a single steam generator.
- d. Following a steam generator tube rupture, closure of the MSIVs isolates the ruptured steam generator from the intact steam generators. In addition to minimizing radiological releases, this enables the operator to maintain the pressure of the steam generator with the ruptured tube below the MSSV setpoints, a necessary step toward isolating the flow through the rupture.
- e. The MSIVs are also utilized during other events such as a feedwater line break. This event is less limiting so far as MSIV OPERABILITY is concerned.
The MSIVs satisfy Criterion 3 of the NRC Policy Statement.
LCO This LC0 requires that [four] MSIVs in the steam lines be OPERABLE. The MSIVs are considered OPERABLE when the isolation times are within limits, and they close on an isolation actuation signal.
This LCO provides assurance that the MSIVs will perform their design safety function to mitigate the consequences of accidents that could result in'offsite exposures comparable to the 10 CFR 100 (Ref. 4) limits or the NRC staff approved licensing basis.
APPLICABI ITY The MSIVs must be OPERABLE in MODE 1, and in MODES 2 and 3 except when closed and de-activated, when there is significant mass and energy in the RCS and steam generators.
When the MSIVs are closed, they are already performing the safety function.
(continued)
WOG STS B 3.7-9 Rev. O, 09/28/92
~
. MSIVs B 3.7.2 l BASES APPLICABILITY In MODE 4, nonnally most of the MSIVs are closed, and the (continued) steam generator energy is low.
In MODE 5 or 6, the steam generators do not contain much energy because their temperature is below the boiling point of water; therefore, the MSIVs are not required for isolation of potential high energy secondary system pipe breaks in these MODES.
ACTIONS A.1 With one MSIV inoperable in MODE 1, action must be taken to restore OPERABLE status within [8] hours. Some repairs to the MSIV can be made with the unit hot. The [8] hour Completion Time is reasonable, considering the low probability of an accident occurring during this time period that would require a closure of the MSIVs.
The [8] hour Completion Time is greater than that norma 11y allowed for containment isolation valves because the MSIVs are valves that isolate a closed system penetrating containment. These valves differ from other containment ,.
isolation valves in that the closed system provides an additional means for containment isolation.
B.1 If the MSIV cannot be restored to OPERABLE status within
[8] hours, the unit must be placed in a MODE in which the LCO does not apply. To achieve this status, the unit must be placed in MODE 2 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and Condition C would be entered. The Completion Times are reasonable, based on operating experience, to reach MODE 2 and to close the MSIVs in an orderly manner and without challenging unit systems. l C.1 and C.2 Condition C is modified by a Note indicating that separate Condition entry is allowed for each MSIV.
Since the MSIVs are required to be OPERABLE in MODES 2 and 3, the inoperable MSIVs may either be restored to i
(continued)
WOG STS B 3.7-10 Rev. O, 09/28/92
MSIVs B 3.7.2 BASES ACTIONS C.1 and C.2 (continued)
OPERABLE status or closed. When closed, the MSIVs are already in the position required by the assumptions in the safety analysis.
The [8] hour Completion Time is consistent with that allowed in Condition A.
For inoperable MSIVs that cannot be restored to OPERABLE status within the specified Completion Time, but are closed, the inoperable MSIVs must be verified on a periodic basis to be closed. This is necessary to ensure that the assumptions in the safety analysis remain valid. The 7 day Completion Time is reasonable, based on engineering judgment, in view of MSIV status indications available in the control room, and other administrative controls, to ensure that these ;
valves are in the closed position. '
O.1 and 0.2 If the MSIVs cannot be restored to OPERABLE status or are not closed within the associated Completion Time, the unit '
must be placed in a MODE in which the LC0 does not apply.
To achieve this status, the unit must be placed at least in MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />, and in MODE 4 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The ;
allowed Completion Times are reasonable, based on operating .
experience, to reach the required unit conditions from l MODE 2 conditions in an orderly manner and without ~l challenging unit systems. '
SURVEILLANCE SR 3.7.2.1 REQUIREMENTS This SR verifies that MSIV closure time is s [4.6] seconds on an actual or simulated actuation signal. The MSIV closure time is assumed in the accident and containment analyses. This Surveillance is normally performed upon returning the unit to operation following a refueling outage. The MSIVs should not be tested at power, since even ,
a part stroke exercise increases the risk of a valve closure l when the unit is generating power. As the MSIVs are not tested at power, they are exempt from the ASME Code, I (continued)
WOG STS B 3.7-11 Rev. O, 09/28/92
. MSIVs B 3.7.2 BASES-SURVEILLANCE SR 3.7.2.1 (continued)
REQUIREMENTS Section XI-(Ref. 5), requirements during operation in MODE 1 or 2.
The Frequency is in accordance with the [ Inservice Testing Program or [18] months] . The [18] month Frequency for valve closure time is based on the refueling cycle.- Operating experience has shown that these components usually pass the Surveillance when performed at the (18] month Frequency.
Therefore, the Frequency is acceptable from a reliability standpoint.
This test is conducted in MODE 3 with the unit at operating temperature and pressure, as discussed in Reference 5 exercising requirements. This SR is modified by a Note that i allows entry into and operation in MODE 3 prior to :
performing the SR. This allows a delay of testing until ;
MODE 3, to establish conditions consistent with those under !
which the acceptance criterion was generated.
l REFERENCES 1. FSAR, Section [10.3] .
- 2. FSAR, Section [6.2] .
- 3. FSAR, Section (15.1.5].
- 4. 10 CFR 100.11.
- 5. ASME, Boiler and Pressure Vessel Code,Section XI, Inservice Inspection, Article IWV-3400.
4 WOG STS B 3.7-12 Rev. O, 09/28/92
9 6
ENCLOSURE 2 TO TXX-94326 NUREG 1024. " Technical Specifications -
Enhancing the Safety Impact",
[Pages 3-3, 3 4, and 4 1 through 4 3]
I pressurizer power-operated relief valve position indicator would invoke i Specification 3.0.3. l Specification 3.3.3.5, Remote Shutdown Instrumentation, is another example of what appears to be an inordinately short allowable out-of-service time taking into account the safety importance of the affected equipment. This specifi-cation requires that with less than one channel of instrumentation available at the remote shutdown panel (e.g., control rod position limit switches), the l inoperable channels are to be restored to operable status within 7 days or i the plant shall be placed in hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
The Task Group believes that resolution of this concern can be accomplished using engineering judgment that should be augmented by analytical risk-based I insights. An analytical tool such as the FRANTIC code is capable of pro- (
viding such insights.
I 3.3 Test Types Particular types of testing called for by the Technical Specifications may be l adverse to safety. Such testing may be the cause of equipment degradation and progressively r, educed system reliability. Alternative forms of testing 1 may be available to enhance overall plant safety.
This concern potentially is applicable to several of the systems addressed in I Section 3 of the Standard Technical Specifications.
An example is Specification 3.8.1, A.C. Sources, which requires that with either an off-site circuit or diesel generator of the required alternating current (ac) electrical power sources' inoperable, demonstrate operability of the diesel generator within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter.
The required test involves starting the diesel generator from ambient condi-tion and accelerating to at least 900 rpm (revolutions per minute) in less than or equal to 10 seconds. Fast cold starts have been demonstrated to cause accelerated degradation of the diesel generators. Further, from a safety standpoint, fast cold starts of diesel generators are required only in the event of the large break loss-of-coolant accident with loss-of-offsite power, a low probability event. However, with ac equipment out of service 1 the plant is more vulnerable to a higher probability event; i.e., loss of all ac power. This event does not require a fast start of the diesel generators.
Fast cold starting of the diesel generators will tend to make the plant more vulnerable to the loss of all ac power because testing the diesel generators in this manner will likely cause further degradation.
The Task Group believes that this concern can be resolved by engineering judgment augmented by insights received from a review of the sequences and consequences associated with the various accident scenarios.
)
3.4 Outage Times Allowable outage times for equipment have been established on the basis of engineering judgment considering the use of standard intervals (e.g., I hour, 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, 7 days). As with test intervals, it is not clear to the Task Group i
3-3
that outage times are optimized from a safety standpoint. Allowable outage times that are too short will subject the plant to unnecessary trips, trans-ients and fatigue cycling. . Outage times that are too short also may result in less thorough repair and post-repair testing before equipment is returned to service. Likewise, outage times that are too long may cause an undesir-able increase in. risk to the public. The Task Group notes that current allow-able outage times are not based on the degree of system fault but rather on go, no-go criteria.
This concern is generally applicable to all of Section 3 of the Standard Technical Specifications. An example is Specification 3.8.1, A.C. Sources, which requires, as a minimum, that the following ac electrical power sources be operable:
. (1) Two physically independent circuits between the offsite transmission network and the onsite Class 1E distribution system, and (2) Two separate and independent diesel generators, each with (a) separate day and engine-mounted fuel tanks containing a minimum volume of fuel, (b) a separate fuel storage system containing a minimum volume and fuel, and (c) a separate fuel transfer pump.
1 Failure to meet conditions 2(a) or 2(b) by even a small amount would require '
testing of the operable diesel generator and would eventually require plant shutdown.
The Task Group believes that resolution of this concern can be accomplished using engineering judgment that should be augmented by risk-based insights. l An analytical tool such as the FRANTIC code is capable of providing such 1 insights. In addition, specifications such as 3.8.1 could be reviewed to determine if a second-level action statement is appropriate. For example, if the volume of fuel is found to be outside of the primary LC0 but within the secondary LCO, then 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> might be an acceptable time to return the volume of fuel to the primar) 'imit before initiating a plant shutdown.
Entry into a second level LCO ,ay require, for example, review by the Plant Safety Review Committee, increased surveillance frequency, and a sumary provided in the annual report with an explanation of the cause, time to remedy, and corrective action.
3.5 Testing After a Failure Some specifications require that if equipment in one train of a system is inoperable, surveillance testing of the equipment in the other train is increased. This has the potential for (1) damaging the redundant system, (2) placing the system or plant in a more vulnerable mode, and (3) failing to return it to an operable condition. Such surveillance strategies may actually degrade the needed system and increase public risk.
3-4 1
4 RECOMMENDATIONS 4.1 Scope of Recomnendations and Priorities The Task Group findings in Section 3 were evaluated to determine the specific reconnendations and their priority. The Task Group established its priori-ties based on (1) the relative safety concern in terms of risk to the public, (2) licensee resource impacts and economic benefits to the licensees, (3) regulatory consistency, and (4) the time frame to resolve the concern.
The Task Group findings were then condensed into five recommendations and prioritized as follows:
Recommendation 1 The testing frequencies in the Technical Specifications should be reviewed to assure that they are adequately supported on a technical basis and that risk to the public is minimized (Findings 3.1 and 3.7).
Recommendation 2 The required surveillance tests should be reviewed to assure that important safety equipment is not degraded as a result of testing and that such tests are conducted in a safe manner and in the appropriate plant operational mode to assu.a that risk to the public is minimized (Findings 3.3, 3.5 and 3.7).
Recommendation 3 The action statements should be reviewed to assure that they are designed to direct the plants to a safe plant operational mode such that public risk is minimized and that unnecessary transients and shutdowns are precluded (Findings 3.2, 3.4, 3.6 and 3.7). ;
Recommendation 4 1
The surveillance test requirements should be reviewed to assure that they do l not consume plant personnel tire unnecessarily or result in undue radiation I exposure to plant personnel without a commensurate safety benefit in terms of minimizing public risk (Findings 3.7, 3.8 and 3.9).
Recommendation 5 The preparation and organization of the Standard Technical Specifications l should be reviewed to assure that they are consistent with 10 CFR 50.36 and i only contain requirements that have a sound safety basis (Findings 3.7, 3.10 and 3.11).
1 4.2 Implementation The Task Group recommends that the responsibility for revising the Technical I Specifications be jointly shared by industry and the NRC staff and that such activities do not hinder or delay ongoing related activities. To assure that 1
4-1
1 1
modifications to tha Technical Specifications are made in a consistent manner, the Task Group recomaends that the implementation of the recommendations I discussed in Sectdon 4.1 be conducted in the following manner:
)
(1) The first step should be to determine on a generic basis the overall l importance of the systems addressed by the Technical Specifications for the four reactor types. A methodology that uses risk importance measures, such as that developed at Battelle Columbus Laboratories and discussed in Section 2.3.2, should be used for that purpose. The product should be an assignment of the systems into high, medium and low categories of relative risk worth. The Task Group recommends that this activity be conducted by the staff with appropriate participation by owners groups.
1 (2) Using each of the four sets of Standard Technical Specifications, the '
Specifications and supporting bases 'for a selected system in the high risk worth category should be evaluated in accordance with reconinenda-tions 1, 2, and 3 and modified as appropriate to assure the following:
(a) The testing frequencies are adequately supported on a technical basis so that risk to the public is minimized.
(b) The surveillance tests do not degrade important safety equipment l as a result of the testing, and that these tests are conducted in a safe manner and in the appropriate plant operational mode so that risk to the public is minimized.
(c) The action statements direct the plant to a safe plant operational .l mode such that public risk is minimized and unnecessary transients '
and shutdowns are precluded.
The Task Group recommends that this activity be conducted by the staff with appropriate participation by owners groups. The staff's evaluation should be conducted using a methodology similar to the FRANTIC code discussed in Section 2.3.1. Engineering judgment, taking these analyses into account should be used to develop the appropriate revisions to the ;
Specifications and their bases. '
(3) The staff should develop a NUREG report describing the procedures used to conduct steps (1) and (2), the changes that could be made to each of the Standard Technical Specifications, and the rationale used to develop the revised bases. This report should be issued to the industry by a generic letter that would encourage changes to the remaining systems with high risk worth using a methodology equivalent to that used by j
the staff. The letter to the industry should strongly urge that these i activities be conducted by owners groups to more efficiently utilize the resources of both the staff and industry and to accomplish changes on an earlier schedule.
(4) The remaining high risk worth systems should be evaluated in accordance with recommendations 1, 2, and 3 as discussed in step (2). However, the 4-2 I l
)
'4_
evaluation and proposed changes to the Standard Technical Specifications -
and their bases should.be accomplished by owners groups and submitted to the staff for generic review and approval.
-(5) Proposed changes to plant-specific Technical Specifications based on the ,
-staff's generic review in steps (3) and (4) should be submitted by licensees and reviewed and approved by the staff in the normal procedure.
At this time the staff would consider the applicability of the generic review to plant-specific Technical Specifications. !
(6) The Technical Specifications.for the medium and low risk worth systems e should be reviewed in.accordance with recomendation 4 to assure that surveillance test requirements do not consume. plant personnel time ^ s unnecessarily or result in undue radiation exposure to' plant personnel without a commensurate safety benefit in terms of a reduction in public risk. That evaluation may be conducted using engineering judgment with appropriate analyses to reflect the severity of requirements for these systems consistent with their importance in reducing public risk. . In doing so, consideration should be given to the use of two-level action statements as discussed in Section 3.4. The use of two-level action statements could avoid unnecessary shutdowns, while at the same time
-assure that the necessary action is taken to restore the equipment to service. The Task Group recommends that this activity be conducted by c
the staff with appropriate participation by owners groups. '
(7) The final step is to review the Technical Specifications for all four ;
nuclear steam supply system suppliers in accordance with recommendation 1 5 to assure that they are consistent with 10 CFR 50.36 and contain only requirements that have a sound safety basis. The Task Group recomends that this activity be conducted by the staff with appropriate partici-
,_ pation by the owners groups.
4.3 Schedule '
The Task Group anticipates that the recommended actions can be completed j within 16 to 18 months after initiation of the NRC program office activities l depending on the priority assigned by industry. The anticipated schedules for individual steps are as follows: .;
Step 1 (staff) -
2 to 3 months from program approval.
Step 2(staff) -
8 to 10 months from program approval.
Requires completion of step 1.
Step 3 (staff) -
8 to 10 months from program approval. 1 Requires completion of step 2.
Step 4(industry / staff) -
8 to 10 months from program approval. ,
Requires completion of step 1. l i
Step 5(industry / staff) -
16 to 18 months from program approval.
Requires completion of steps 1-4. .
1 4-3 )
i ENCLOSURE 3 TO TXX 94326 l
Amendment 149 to License No. OPR 72, l
" Crystal River Unit 3 Technical Specifications",
[Page 3.7-4, 3.7 5, and B 3.7 7 through B 3.7 12]
l
7 MSIVs
, '3.7.2 3.7 PLANT SYSTEMS 3.7.2 Main Steam Isolation Valves (MSIVs)
LCO 3.7.2 Each MSIV shall be OPERABLE.
APPLICABILITY: MODES 1, 2, and 3.
ACTIONS
NOTE-----------------------------_-------
Enter applicable Conditions and Required Actions.for Turbine Bypass Valves (TBVs) made inoperable by MSIV(s).
CONDITION ~ REQUIRED ACTION COMPLETION TIME
NOTE-----------
Separate Condition entry A.1 Close inoperable 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> is allowed for each MSIV. MSIV(s).
kND A. One or more MSIV inoperable on one A.2 Verify inoperable Once per 7 days steam generator. MSIV(s) is closed.
B. Required Action and B.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> associated Completion Time not met. AND B.2 Be in MODE 4. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Crystal River Unit 3 3.7-4 Amendment No. 149
?> MSIVs 3.7.2 SURVEILLANCE RE0VIREMENTS SURVEILLANCE FREQUENCY SR 3.7.2.1 -------------------NOTE--------------------
Only required to be performed in MODES 1 and 2.
Verify closure time of each MSIV is in In accordance accordance with the Inservice Testing with the Program. Inservice Testing Program 1
I l
l Crystal River Unit 3 3.7-5 Amendment No. 149
MSIVs 8 3.7.2 8 3.7 PLANT SYSTEMS B 3.7.2 Main Steam Isolation Valves (MSIVs)
BASES BACKGROUND The principal function of the main steam isolation valves (MSIVs) is to isolate steam flow from the secondary side of the steam generators (OTSGs) following a steam line break (SLB). In the event of a SLB, closure of the MSIVs provides additional steam side isolation to that provided by the turbine stop valves and terminates flow from the unaffected (intact) OTSG. This closure terminates SLB events occurring downstream of the MSIVs. A transient such as increased steam flow through the turbine bypass valves causing low steam generator pressure would also be terminated by closure of the MSIVs.
One MSIV is located in each of four main steam lines outside, but close to, containment. The MSIVs are located downstream of the main steam safety valves (MSSVs) and steam supply lines to the emergency feedwater (EFW) pump turbine to prevent isolation of these critical steam loads in the event of MSIV closure. Closure of the MSIVs isolates the OTSGs from the turbine, turbine bypass valves, and other auxiliary steam loads.
The MSIVs are spring actuated, pneumatically-operated valves which are opened / assisted-closed by instrument air pressure (Ref. 1). These valves close on receipt of a main steam line isolation signal generated by the Emergency Feedwater Initiation and Control (EFIC) System based upon low OTSG pressure. The main steam lines can also be manually isolated from the control room.
A description of the MSIVs is contained in FSAR, Section 10.2.1.4 (Ref. 2). In isolating the main steam lines, the MSIVs satisfy 10 CFR 50 Appendix A General Design Criteria (GDC) 57 requirements for isolation of closed system lines which penetrate containment (Ref. 3).
(continued)
Crystal River Unit 3 8 3.7-7 Amendment No. 149
W;, . *'
' B 3.7.2 BASES (continued)
APPLICABLE The MSIV LCO was derived from the analysis of postulated SLB SAFETY ANALYSIS accidents. In the analyses of SLBs inside or outside of containment which were performed prior to the development of the EFIC System, MSIV closure occurs in parallel with turbine stop valve closure to prevent blowdown of both OTSGs. With the addition of the EFIC System, the MSIV closure on an EFIC isolation signal was evaluated and determined to be equivalent _to the closure of the turbine i
stop valves. The SLB analyses assumed turbine stop valve '
closure at 7 seconds after the break. MS isolation, assuming development of the signal and MSIV closure within the same 7 second timeframe is conservative (i.e. more steam is released considering turbine stop valve closure than MSIV closure).
There'are several reasons why all MSIVs are isolated on an EFIC MS isolation, including those on the intact generator.
Restricting the blowdown to a single OTSG is necessary to limit the positive reactivity effects associated with the resulting Reactor Coolant System (RCS) cooldown, as well as to prevent containment overpressurization in the event of a break within the reactor building coincident with the failure of feedwater to isolate. (Ref. 4). Additionally, MSIV closure ensures that at least one OTSG remains available for RCS cooldown and capable of supplying steam to the turbine driven EFW pump.
Several analysis.SLB variations are considered in the accident In all cases except the rupture of all four main steam lines, isolation of the main steam lines was assumed.
Steam line isolation prevents a single break from affecting both OTSGs, allowing the unaffected OTSG to be used for RCS heat removal. A controlled cooldown can then be maintained, through operation of the EFW system and steam relief through the atmospheric dump valves or turbine bypass valves.
L In the event of a single MSIV failure coincident with an SLB 3 accident, closure of the three remaining MSIVs will prevent !
continued, simultaneous blowdown of both OTSGs. Thus, the accident analysis has shown the SLB can be mitigated even with the failure of a single MSIV.
t (continued) f.
Crystal River Unit 3 8 3.7-8 Amendment No. 149 u
MSIVs B 3.7.2 BASES APPLICABLE In. contrast with the postulated SLB events, the MSIVs are SAFETY ANALYSIS -assumed to be open following a steam generator tube rupture (continued) (SGTR) accident. Following a SGTR, activity and inventory contained within the RCS is leaked into the MS System, where it is then available for release to the environment. In the evaluation of offsite dose following a SGTR, the-turbine bypass valves (TBVs) were used to establish and maintain RCS cooldown, directing the leaked reactor coolant to the condenser. Within the condenser, a partial removal of iodine was considered, effectively reducing the total quantity of radioactivity contributing to the post-accident offsite dose. Although the resultant offsite dose is-predicted to be considerably less than the guidelines of 10 CFR 100, the ability to maintain the MSIVs open is essential to keeping offsite doses within analyzed values (Ref. 5).
The MSIVs satisfy Criterion 3 of the NRC Policy Statement.
LC0 This LCO requires that all four MSIV be OPERABLE. The MSIVs are considered OPERABLE, for this Specification, when the isolation times are within limits and they close on an EFIC isolation actuation signal. Containment isolation requirements for the MSIVs are addressed in LCO 3.6.3.
MSIVs that are closed and deactivated are considered OPERABLE since they are already performing the safety function and the administrative controls to ensure function are adequate. However, the TBVs may not be OPERABLE under these circumstances. The Required Actions of LCO 3.7.4 are required to be entered in this situation if the IBV are determined to be inoperable as a result of MSIV closure and deactivation.
This LCO provides assurance that the MSIVs will perform their design safety function to mitigate the consequences of accidents that could result in offsite exposures comparable to the 10 CFR 100 limits (Ref. 6).
APPLICABILITY The MSIVs must be OPERABLE in MODES 1, 2, and 3 since there is significant mass and energy in the RCS and 0TSG and the potential for a SLB exists.
(continued)
Crystal River Unit 3 8 3.7-9 Amendment No. 149
.,* MSIVs B 3.7.2 BASES APPLICABILITY In MODES 4, 5, and 6 the pressure and temperature in the (continued) OTSGs is markedly reduced. Therefore, the MSIVs are not required for isolation of potential high energy secondkry-system pipe breaks in these MODES.
ACTIONS The ACTIONS are modified by a Note which ensures appropriate remedial actions are taken in the event the turbine bypass valves, addressed in LCO 3.7.4, are rendered inoperable by a closed MSIV (MSV-411 or MSV-413). With the MSIV closed in accordance with Required Action A.1, the T8Vs can be cons.dered OPERABLE provided the MSIV, and in-turn, the TBVs, are capable of being opened within the time frame assumed in the SGTR analysis (8 minutes) and appropriate .
procedural controls are in-place to ensure the alternate manur 'ction is completed in the event of a SGTR. This pWc ny is consistent with the guidance provided in NRC Gener Letter 91-18 on utilizing a manual action for an otherwise automatic function for the purposes of determining OPERABILITY.
This Note is an LCO 3.0.6 type exception, since LCO 3.0.6 would dictate the ACTIONS of Specification 3.7.4 should not be taken if the TBV is rendered inoperable solely as a result of the inoperable MSIV. In this case, it is appropriate to enter the Conditions and Required Actions of Specification 3.7.4 when one or more TBV is inoperable.
A.1 and A.2 With one ar more MSIV inoperable on one OTSG, action must be taken to restore the component (s) to OPERABLE status or close the valve (s) within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. The 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> Completion Time is reasonable, considering the probability of an accident that would require actuation of the MSIVs occurring during this time interval. The turbine stop valves are available as backup to provide the required isolation for the majority of postulated accidents which require OTSG isolation.
Valves closed in accordance with Required Action A.1 must be ;
verified to be closed on a periodic basis. This is '
necessary given the valves are not required to be deactivated, to ensure the assumptions of the safety .
- (continued) ,
)
Crystal River Unit 3 B 3.7-10 Amendment No. 149
-l 20^
9 .MSIVs I
- L 'B 3.7.2 )
l BASES j
' ACTIONS A.1 and A.2 (continued). J 1
analysis remain valid..,The 7 day Completion Time is reasonable, based upon engineering judgement, in view of MSIV status indication in the control ~ room, and other administrative controls, to ensure the valves remain in the closed position. l I
B.1 and B.2 ,
If the Required Action and associated Completion Time are not met, the plant must be placed in a MODE in which the LC0 does not apply. To achieve this status, the plant must be '
placed in at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in MODE 4 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The allowed Completion Times'are reasonable, based.on operating experience, to reach the ;
required plant conditions from full power conditions in an '
orderly manner and without challenging plant systems.
SURVEILLANCE SR 3.7.2.1 REQUIREMENTS
. This SR verifies that the closure time of each MSIV.is in accordance with the limit specified in the Inservice Testing Program.
This MSIV closure time is established based upon design specifications for the' valves and is consistent with the accident and containment analyses. This Surveillance is normally performed upon returning the plant to operation following a refueling. outage, because the MSIVs should not be tested at power since even a part stroke exercise increases the risk of a valve closure with the plant 1 i
generating power. As the MSIVs are not to be tested at power, they are exempt from the ASME Code,Section XI (Ref. 7) quarterly valve stroke requirements.
The Frequency for this SR is in accordance with the Inservice Testing Program and is based on the typical refueling cycle. Operating experience has shown that these components usually pass the Surveillance when performed at {
this Frequency. Therefore, the- Frequency was concluded to be acceptable from a reliability standpoint.
J l
1 (continued)
Crystal River Unit 3 B 3.7-11 Amendment No. 149 l
MSIVs y I' . -
8 3.7.2 BASES SURVEILLANCE SR 3. 7. 2. l' (continued)
This SR is modified by a Note that allows entry into and operation in MODE 3 prior to performing the SR. This allows delaying testing until MODE 3 in order to establish plant conditions most representative of those under which the acceptance criterion was generated.
REFERENCES 1. Enhanced Design Basis Document for the Main Steam System, Revision 3, dated January 31, 1990, with Temporary Changes 184, 203, 253, and 254.
- 2. FSAR, Section 10.2.1.4.
- 4. FSAR, Section 14.2.2.1.7.
- 5. FSAR, Section 14.2.2.2.
- 6. 10 CFR 100.
- 7. ASME, Boiler and Pressure Vessel Code,Section XI,.
Inservice Inspection, Article IWV-3400.
Crystal River Unit 3 8 3.7-12 Amendment No. 149
._