ML20155C159
| ML20155C159 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 09/28/1988 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20155C157 | List: |
| References | |
| NUDOCS 8810070261 | |
| Download: ML20155C159 (12) | |
Text
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ATTACIMDfI_A P ROFDS E D_Cil AN G E S._TQ_ AEE EN DIK_A IICIDILCA L_S EICI rlCATICtLOE_fACIL LTY QEE RAT IN G_ L ICIN S E S_11 Ef -1L._N Ef2614_ll ET21LRI D_B Ef_15 BYRCtLSTAIlott BRAIDH000__ STAT 10tl Revised Pagest 3/4 1-14 Revised Pages 3/4 1-14 3/5 1-15 3/4 1-15 B 3/5 1-4 B 3/4 1-4 I
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REACTIVITY CONTROL SYSTEMS
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3/4.1.3 HOVABLE CONTROL ASSEMBLIES GROUP HEIGHT LIMITING CON 0! TION FOR OPERATION 3.1. 3.1 All full-length shutdown and control rods shall be OPERABLE and positioned within 2 12 steps (indicated position) of their group step counter demand position.
APPLICABILITY:
MODES la and 2*,
ACTION:
a.
With one or more full-length rods inoperable due to being immovable as a result of excessive friction or mechanical interference or known to be untrippable, determine that the SHUT 00WN MARGIN require-ment of Specification 3.1.1.1 is satisfied within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
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b/.
With one full-length rod trippable but inoperable due to causes ether than addressed by ACTION a. above, or misaligned from its group step counter demand height by more than 2 12 steps (indicated position), POWER OPERATION may continue provided that within I hour:
1 1.
The rod is restored to OPERABLE status within the above alignment requirements, or 2.
The rod is declared incperable and the remainder of the rods in the group with the inoperable rod are aligned to within 2 12 steps of the inoperable rod while maintaining the rod sequence and insertion limits of Figure 3.1-1.
The THERMAL POWER level shall be restricted pursuant to Specification 3.1.3.6 during subsequent operation, or 3.
. The rod is declared inoperable and the SHUTOOWN MARGIN requirement of Specification 3.1.1.1 is satisfied.
POWER OPERATION may then continue provided that:
a)
The THERMAL POWER level is reduced to less than or equal to 75% of RATED THERMAL POWER within the next hour and within the following 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> the High Neutron Flux Trip betpoint is reduced to less than or equal to 85% of RATED THERMAL POWER.
b)
The SHUTDOWN MARGIN requirement of Specification 3.1.1.1 is determined at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />;
- See Special Test Exceptions Specifica+. ions 3.10.2 and 3.10.3.
f BYRON - UNITS 1 & 2 3/4 1-14 i
1 E
REACTIVITY CONTROL SYSTEMS LIMITING CONDITION FOR OPERATION ACTION (Continued) c)
A power distribution map is obtained from the movable incoredetectorsandF(Z)andFhareverifiedtobe 9
within their limits within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; and I
d)
A reevaluation of each accident analysis of Table 3.1-1 is performed within 5 days; this reevaluation shall confirm that the previously analyzed results of these accidents remain valid for the duration of operation under these conditions; C,.
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j SURVEILLANCE REQUIREMENTS 4.1.3.1.1 The position of each full-length rod shall be determined to be within the group demand limit by verifying the individual rod positions at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> except during time intervals when the rod position deviation monitor is inoperable, then verify the group positions at least aqce per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
4.1. 3.1. 2 Each full-length rod not fully inserted in the core shall be determined OPERABLE by movement of at least 10 steps in any one direction at least once per 31 days.
BYkON - UNITS 1 & 2 3/4 1-15
REACTIVITY CONTROL SYSTEMS BASES MOVABLE CONTROL ASSEMBLIES (Continued) 18, 210, and 228 steps withdrawn for the Shutdown Banks provides assurances that the Digital Rod Position Indicator is operating correctly over the full range of indication.
Since the Digital Rod Position System does not indicate the actual Shutdown rod position between 18 steps and 210 steps, only points in the indicated ranges are picked for verification of agreement with demanded
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, Sin 3k, We dic TheACTIONstatementswhichh(ermitlimited tions from the basic requirements are accompanied by aqditional restrict ns whi'ch ensure that the original design critaria are met.'</isalignment of rod requires measurement of peaking factors and a restriction in THERMAL POWER.
These restrictions provide assurance of fuel rod integrity during continued operation.
In addition, those safety analyses affected by Xgnitaligned rod are reevaluated to confirm that the results remain valid during
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The maximum rod drop time restriction is consistent with the assumed rod drop time used in the safety analyses.
Measurement with T,yg greater than or equal to 550*F and with all reattor coolant pumps operating ensures that the measured drop times will be representative of insertion times experienced during a Reactor trip at operating conditions.
Control rod positions and OPERABILITY of the red position indicators are required to be verified on a nominal basis of once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> with more frequent verifications required if a rod position deviation monitor is inoper-able.
These verification frequencies are adequate for assuring that the applicable LCOs are satisfied.
I BYRON UNITS 1 & 2 B 3/4 1-4
O Insert to page 3/41-15 c.
With more than one full-length rod trippable but inoperable due to causes other than addressed by ACTION a. above, or misaligned from its group step counter demand height by more than 112 steps (indicated postion),
POWER OPERATION may continue provided that:
1.
Within I hour, the remainder of the rods in the group (s) with the inoperable rods are aligned to within 112 steps of the inoperable rods while maintaining the rod sequence and insertion limits of Figure 3.1-1. The T!!ERM AL POWER level shall be restricted pursuant to Specification 3.1.3.6 during subsequent operation, and 2.
The Inoperable rods shall be restored to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Otherwise, be in !!OT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
Insert to page B3/41-4 (continue with paragraph)
With multiple inoperable or misaligned, but trippable, rods; alignment af the remaining rods in the bank (s) to within 112 steps of the inoperabic rods, and restriction in TilERMAL POWER assures fuel rod integrity during continued operation.
For Specification 3.1.3.1 ACTIONS b. and c.. It is incumbent on the plant to confirm trippability of the inoperable rod (s). This confirmation may be, for example, by verification of a control system failure, usually electricalin nature l
(such as an Urgent Failure Alarm), or that the failure is associated with the control rod stepping mechanism. In the event the plant is unable to verify i
the rod (s) trippability, it must be assumed to be untrippable and thus falls under the requirements of ACTION a.
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e49/065
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REACTIVITY CONTROL SYSTEMS k'
3/4.1.3 MOVABLE CONTROL ASSEMBLIES i
GROUP HEIGHT 1
LIMITING CONDITION FOR OPERATION j
3.1.3.1 All full length shutdown and control rods shall be OPERABLE and positioned within 1 12 steps (indicated position) of their group step counter demand position.
APPLICABILITY: MODES la and 2".
ACTION:
a.
With one or more full-length rods inoperable due to being immovable as a result of excessive friction or mechanical interference or known to be untrippable, determine that the SHUT 00VN MARGIN require-ment of Specification 3.1.1.1 is satisfied within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and be in H07 STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
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-b.
Wf th-meet-Ban-one-f ttWength rod -inoperaMe-oe-mtiaMgned-f rom-the group-+tep-<ount+r de and-pont4cn-by-mor+-than-t-12-step 5-findicated>
posit 4en)rbe-in HO!=$rTMOBY-w& thin-6-houry i
[6 With one full-length rod trippable but inoperable due to causes other than addressed by ACTION a. above, or misaligned from its group step counter demand height by more than 212 steps (indicated position), POWER OPERATION may continue provided that within 1
[
hour:
1.
The rod is restored to OPERABLE status within the abnve alignment requirements, or 2.
The rod is declared inoperable and the remainder of the rods in the group with the inoperable rod are aligned to within 1 12 steps of the inoperable rod while maintaining the rod sequence and insertion limits of Figure 3,1-1.
The THERMAL POWER level shall be restricted pursuant to Specification 3.1.3.6 during subsequent operation, or l
3.
The rod is declared inoperable and the SHUTDOWN MARGIN requirefrent of Specification 3,1,1.1 is satisfied.
POWER h
OPERATION may then continue provided that:
a)
The THERMAL POWER level is reduced to less than or equal to 75% of RATED THERMAL POWER within the next hour and i
within the following 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> the High Neutron Flux Trip Setpoint is reduced to less than or equal to 85% of RATED THERMAL POWER.
t:)
The SHUTDOWN MARGIN requirement of Specification 3.1.1.1 is determined at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />; "See Special Test Exceptions Specifications 3.10.2 and 3,10.3.
BRAIDWOOD - UNITS 1 & 2 3/4 1-14
(,
REACTIVITY CONTROL SYSTEMS LIMITING CONDITION FOR OPERATION i
ACTION (Continuedj c)
A power distribution map is obtained from the movable incoredetectorsandF(Z)andFhareverifiedtobe g
within their limits within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />; and d)
A reevaluation of each accident analysis of Table 3.1-1 is performed within 5 days; this reevaluation shall confirm that the previously analyzed results of these accidents remain valid for the duration of operation under these conditions;
(, ( f,s,.rt M A Ael>~ c., A SURVE!LLANCE REQUIREMENTS 4.1.3.1.1 The position of each full length rod shall be determined to be within the group demand limit by verifying the incividual rod position? at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> except during time intervals when the rod position deviation monitor is inoperable, then verify the group positions at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
4.1.3.1.2 Each full-length rod not fully inserted in the core shall be determined OPERABLE by movement of at least 10 steps in any one direction at least once per 31 days.
BRAIDWOOD - UNITS 1 & 2 3/4 1 15
REACTIVITY CONTROL SYSTEMS BASES
$VABLECONTROLASSEMBLIES(Continued) 18, 210, and 228 steps withdrawn for the Shutdown Banks provides -assurances
,1 that the Digital Rod Position Indicator is operating correctly over the full range of indication.
Since the Digital Rod Position System does not indicate the actual shutdown rod position between 18 steps and 210 steps, only points in the indicated ranges are picked for verification of agreement with demanded hl e.,4-i e l
EI k.ca.hh ce The ACTION statements which, permit limited variations /from the basic 1
original design criteria are met.'"' Misalignment of agns"which ensure that th requirements are accompanied by(additional restrictio rod requires measurement of peaking factors and a restriction tii THERMAL POWER.
These restrictions provide assurance of icel rod integrity during continued operation.
In addition, misaligned rod are reevaluated to confirm those safety analyses af fected by,a'D future _pgion.* 4 a.na s* A W'8 that the results remain valid during Inwt g,, mc pN.le ed The maximum rod drop time restriction is consistent with the assumed rod drop tim + used in the ufety analyses.
Measur:::nt '>ith T,yg greater than er equal to 550'F and with all reactor coclant pumos operating ensures that the measured drop times will be representative of insertion times experienced during a Reactor trip at operating conditions.
1 Control rod positions ana OPERABILITY of the rod position indicators are required to be verified on a nominal basis of once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> with more frequent verifications required if a rod position deviation monitor is inoper-1 able.
These verification frequencies are adequate for assuring that the I
applicable LCOs are satisfied, t
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k BRA 10W000 - UNITS 1 & 2 B 3/4 1-4
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. Insert to page 3/41-15 e.
With more than one full-length rod trippable but inoperable due to causes i
other than addressed by ACTION a. above, or misaligned from its group
?
step counter demand height by more than + 12 steps (Indicated postion).
POWER OPERATION may continue provided that:
1.
Within I hour, the remainder of the rods in the group (s) with the Inoperable rods are aligned to within + 12 steps of the Inoperable rods while maintaining the rod sequence and insertion limits of Figure 3.1-1. The THERM AL POWER level shall be restricted pursuant to specification 3.1.3.6 during subsequent operation, and 2.
The Inoperable rods shall be restored to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Otherwise, be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
. Insert to page B3/41-4 (continue with paragraph)
With multiple inoperable or misaligned, but trippable, rods: alignment of the remaining rods in the bank (s) to within ; 12 steps of the inoperable rods, and restriction in THERMAL POWER assures fuel rod integrity during continued operation.
For Specification 3.1.3.1 ACTIONS b. and c.. It is incumbent on the plant to confirm trippability of the Inoperable rod (s). This confirmation may be, for example, by verification of a control system failure, usually electricalin nature (such as an Urgent Failure Alarm), or that the failure is associated with the control rod stepping mechanism. In the event the plant is unable to verify the rod (s) trippability,it must be assumed to be untrippable and thus falls under the requirements of ACTION a.
- 49/065 i
ATTACllMENT_B DE S C RI ET IDtl AN D_ SUmiARLO LP R0POS E D_CIIAN G E S The proposed changes involve Technical Specification 3.1.3.1, Moveable Control Assemblies, Action Statements b and c and the Bases Section for this specification for the Byron and Braldwood Stations. This change is to address multiple Inoperable, but trippable, control rods. This condition exists when a group or several gioups of control rods become Immovable by a rod control system failure.
In this situation, the control rods will not step in or out, but will drop if a reactor trip were initlated.
The Technical Specifications currently do not recognise the fact that in this situation the control rods would still perform their safety function.
Yet, because more than one control rod is immovable, the plant is forced to repair the f ailure or be in HOT STANDBY in six hours. Westinghouse believes this drastic action is unnecessary and the NRC has allowed Shearson Harris, Seabrook, Vogtle South Texas and Hillstone to change their Technical Specifications to address this situation.
The Byron and Braidwood Technical Specification 3.1.3.1, Action Statement b, would be expanded to address multiple immovable, but trippable, control rods.
Specifically, the action statement would permit power operation when more than one rod is trippable, but inoperable, provided that within one hour the remainder of the rods in the group (s) with the inoperable rods are I
aligned to within 112 steps of the inoperable rods while maintaining the rod sequence and rod insertion limit. This condition would be permitted until the inoperable rods are restored to an operable status, but, not to exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Otherwise, the unit must be placed in HOT STANDBY within the next six hours.
It is incumbent on the plant to confirm trippability of the Inoperable control rod (s).
In the event the plant is unable to verify trippability, the control rod (s) must be assumed to be untrlppable and thus, Action A will apply. The Basis Section for this specification would be changed to reflect this condition.
5170K
9 ATIACitiENLC EVALUATIOtLQ L S I GNRIC AHLilA Z ARD S_. CON SI D E R ATION Commonwealth Edison has evaluated this proposed unendment and determined that it involves no significant hasards considerations. According to 10 CFR 50.92(c), a proposed unendment to an opersting license involves no significant hasards considerations if operation of the faellity in accordance with the proposed snendment would nots (1)
Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3)
Involve a significant reduction in the margin of safety.
This change will provide new Action Statement requirements to Specification 3.1.3.1 to restrict rod movement and thermal power levals with multiple inoperable, but trippable, control rods.
This change addresses the situation where more than one rod is inoperable / immovable.
In this condition the rods are unable to provide the normal control function, however, the safety related function of trippability la unaffected. This situation can be caused, for example, by a blown fuse in the non-safety related control circuitry.
The previously evaluated accident conditions applicable to this change are the possible rod misalignment, rod ejection, and dropped rod scenarios.
These accidents have been analysed in Chapter 15 of the FSAR.
The proposed netton requirement changes ensure that the control rod configuration is kept within the bounds of the configurations assumed for these analyses.
If rods are misaligned and cannot be brought to within the alignment limits, the Action Statement requires that the plant be placed in llOT SilUTDOWN within sis hours. This time limit is unchanged from the current specification.
In addition, a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> time limit is placed on operation while in this Action Statement to prohibit indefinite operation with reatricted operational flexibility. Therefore, this change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
This change does not involve any modification la the operational limits or physical desian of the control rod drive mechanisms.
The revised action requirements assure that the control rods and thermal power level are restricted to within the configurations analysed in the FSAR.
As such, the change to the Action Statement does not create the possibility of a new or j
different kind of accident from any previously analysed.
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The revised action requirements restrict rod movement and thermal power level in accordance with the limit of existing Technical Specifications.
No new limits are made and conditions in the reactor after completing the action requirement will be within normal operating ranges. Therefore, the j
changes do not involve a significant reduction in the margin of safety.
-l Based on the above considerations, Commonwealth Edison has determined i
that these changes involved no significant hazards consideration.
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