ML19312B961
ML19312B961 | |
Person / Time | |
---|---|
Site: | Oconee ![]() |
Issue date: | 12/31/1973 |
From: | DUKE POWER CO. |
To: | |
Shared Package | |
ML19312B960 | List: |
References | |
NUDOCS 7911270745 | |
Download: ML19312B961 (11) | |
Text
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3.5.2 control Rod Group and Power Distribution Limits Applicability This specification applies to power distribution and operation of control rods during power operation.
Obiective To assure an acceptable core power distribution during power operation, to set a limit on potential reactivity insertion from a hypothetical control rod ejection, and to assure core subcriticality after a reactor trip.
Specification 3.5.2.1 The available shutdown margin shall be not less than 1% Ak/k with the highest worth control rod fully withdrawn.
3.5.2.2 Operation with inoperable rods:
Operation with more than one inoperable rod,as defined in a.
Specification 4.7.1 and 4.7.2.3, in the safety or regulating rod groups shall not be permitted.
b.
If a control rod in the regulating or safety rod groups is declared inoperable in the withdrawn position as defined in Specification 4.7.1.1 and 4.7.1.3, an evaluation shall be initiated immediately to verify the existance of 1% Ak/k hot shutdown margin.
Boration may be initiated either to the worth of the inoperable rod or until the regulating and transient rod groups are fully withdrawn, whichever occurs first.
Simultaneously a program of exercising the remain-
)
ing regulating and safety rods shall be initiated to verify operability, c.
If within one (1) hour of determination of an inoperable rod as defined in Specification 4.7.1, it is not determined that a 1% Ak/k hot shutdown margin exists combining the worth of the inoperable rod with each of the other rods, the reactor snall be brought to the hot standby condition i
until this margin is established.
d.
Following the determination of an inoperable rod as defined in Specification 4.7.1, all rods shall be exercised within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and exercised weekly until the rod problem is sol-ved.
e.
If a control rod in the regulating or safety rod groups is declared inoperable per 4.7.1.2, power shall be. reduced to 60% of the thermal power allowable for the reactor cool-ant pump combination.
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c.
Except for physics tests or exercising control rods, the control rod withdrawal limits are specified on Figures 3.5.2-1A1, 3.5.2-1B1, 3.5.2-1A2, and 3.5.2-1B2 for four pump operation and on Figure 3.5.2-2A and 3.5.2-2B for three or two pump operation.
If the con-trol rod position limits are exceeded, corrective measures shall be taken immediately to achieve an acceptable control rod position.
Acceptable control rod positions shall be attained within four hours.
d.
Except for physics tests, power shall not be increased above the power level cutoff (see Figures 3.5.2-1) unless the xenon reactivity is within 10% of the equilibrium value for operation at rated power and j asymptotically approaching stability.
i 3.5.2.6 Reactor Power Imbalance shall be monitored on a frequency not to exceed two hours during power cperation above 40 percent rated power.
Except for physics tests, imbalance shall be maintained within the envelope defined by Figure 3.5.2-3A and 3.5.2-3B.
If the imbalance is not within the envelope defined by Figure 3.5.2-3A and 3.5.2-3B, corrective measures shall be taken to achieve an acceptable imbalance.
If an acceptable imbalance is not achieved within four hours, reactor power shall be reduced until imbalance limits are met.
3.5.2.7 The control rod drive patch panels shall be locked at all times with limited access to be authorized by the superintendent.
Bases The power-imbalance envelope defined in Figure 3.5.2-3A and 3.5.2-3B is based on LOCA analyses which have defined the.cximum linear heat rate (see Figure 3.5.2-4) such that the maximum clad temper o 1111 not exceed the Interim Acceptance Criteria.
Corrective measures w..
ou taken immediattly should the indicated quadrant tilt, rod position, or imbalance be outside tLsir specified boundary.
Operation in a situa* ton that would cause the interim acceptance criteria to be approached should a LOCA occur is highly improbable because all of the power dis-tribution parameters (quadrant tilt, rod position, and imbalance) must be at their limits while simultaneously all other engineering and uncertainty factors are also at their limits.* Conservatism is introduced by application of:
a.
Nuclear uncertainty factors b.
Thermal calibration c.
Fuel densification effects d.
Hot rod manufacturing tolerance factors The 30 percent overlap between successive control rod groups is allowed since the worth of a rod is lower at the upper and lower part of the stroke.
Control rods are arranged in groups or banks defined as follows:
- Actual operating limits depend on whether or not incore or excore detectors are used and their respective instrument and calibratien errors.
The method used to define the operating li=its is defined in plant operating procedures.
1 3.5-8 4
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3 5
5 l
l 1
ROD INDEX I S THE PERCENTAGE SUM OF THE WITHDRAWAL OF THE OPER ATING GROUPS.
2.
THE ADDI TION AL RESTRICTI ONS 0.J W I THDR AW AL (H ASHED ARE A) ARE IN EFFECT AFTER 285 FULL POWER DAYS OF OPERATION.
125 188 235 284 100 92
/
172 250 POWER 80 RESTRICTED REGION LEVEL CUT 0FF j
PERMISSIBLE OPERATING u
j GO 8
REGION
<=
~
5 e
40
g a.
20 t
t t
g g
50 100 150 200 250 300 Rod Index,"
Withdrawal 0
25 50 75 100 I
I t
I a
0 25 50 75 100 GROUP 7 i
i GROUP 8 0
25 50 75 t00 J
GROUP 5 CCNTROL R00 GROUP WITH0RAWAL LIMITS FOR 4 PUMP OPERATION l
UNIT 1 l
onthn) OCONEE NUCLEAR STATION 3.5-8b s
Figure 3.5.2-1A1
3 I
I g
g 1
ROD INDEX I S THE P ERCENTAGE SlM OF THE WI THDR AWAL OF THE OPER ATt NG GROUPS.
2 THE ADDITION AL RESTRI CTI ONS ON WI TH DR A A AL (H ASHED ARE A) ARE IN EFFECT AFTER 285 FULL PO*ER DAYS OF OPERATION.
125 265 284 100 f
q M
E 92 -
POWER LEVEL J 246 RESTRICTED AEGION 3
CUTOFF
=
[
80 WITH0RAWAL LIMIT o
et N
N S
60 y
PERMISSIBLE OPERATING REGION g
40
~
20 0
i i
i 50 100 150 200 250 300 Rod index, 5 Withdrawal 0
25 50 75 100 8
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0 25 50 75 100 GROUP 7 i
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25 50 75 100 GROUP 6 i
t f
g g
GROUP 5 CONTROL R00 GROUP WITH0RAWAL LIMITS FOR 4 PUMP OPERATION UNIT 1 3.5-8c (mteowta OCONEE NUCLEAF STATION j
Figure 3.5.2-1 A2 l
w.
)
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s 1.
ROD INDEX I S THE PERCENTAGE SUM OF THE WITHORAWAL OF TH E OP ER AT I NG GROUP S.
- 2. THE ADDITIONAL RESTRICTIONS ON WITHDRAAAL (HASHED AREAS) ARE MODI FI ED AFTER 435 FULL POWER D AYS OF OPERATION. (SEE FIGURE 3.5.2 1B) 291.4 WITH0RAWAL LIMIT 125 189 246 100 90 85.5.__
b 182 264
=
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POWER y 80 RESTRICTED y,
REGION l.EVEL CUT 0FF M
60 g
.d PERMISSIBLE
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OPERATING
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f g
REGION f
h 40 20 t
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50 100 150 200 250 300 Rod index, 'I Withdrawal 0
25 50 75 100 I
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t I
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25 50 75 100 i
f f
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Group 6 0
25 50 75 100 t
t t
t I
Group 5 CONTROL R00 GROUP WITH0RAWAL LIMITS FOR 4 PUMP OPERATION m UNIT 2 3 5-Sd
'gou rma OCONEE NUCLEAR STATION Figure 3.5.2-181
s
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e a
i s
i 1
ROD INDEX l S THE PERCENTAGE SUM OF THE WI THDRAWAL OF THE OPERATING GROUPS.
2 THE ADDITIONAL RESTRI CTlONS ON WI THDRAWAL (HASHED AREAS) ARE IN EFFECT AFTER 435 FULL POWER DAYS OF OPERATION.
291.4 125 270 100
,j 90 85.5 -
POWER ]
f 80 250 RESTRICTED g
REGION LEVEL Withdrawal Limit j
CUT 0FF 60 k
PERMISSIBLE g
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o s
OPERATING 2
g O
REGION 40
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f f
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1 50 100 150 200 250 300 Rod Index.
') Withdrawal 0
25 50 75 100 e
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1 I
Group 7 0
25 50 75 100 l
i f
f I
Group 6 0
25 50 75 100 t
t t
t i
Group 5 CONTROL R00 GROUP WITH0RAWAL LIMITS FOR 4 PUMP OPERATION UNIT 2 3.5-8e k OCONEE NUCLEAR STATION Figure 3.5.2-182
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1 1
ROD INDEX 1 S THE PERCENTAGE SUM OF THE #1 THDRAWAL OF THE OPERATING GROUPS.
5; a
b100 125 291.4 s
u
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RESTRICTED REGION g 80 5
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PERMISSIBLE
=
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2 REGION 3
40 e
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50 100 150 200 250 300 Rod index, $ Withdrawal 0
25 50 75 100 R
R R
t I
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25 50 75 100 f
f i
e Group 6 0
25 50 75 100 e
i t
t l
Group 5 CONTROL R00 GROUP WITH0RAWAL LIMITS FOR 3 AND 2 PUMP OPERATION i
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UNIT 1 3.5-8f
- ent row OCONEE NUCLEAR STATION l
Figure 3.5.2-2A I
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i t.
ROD INDEX t S THE PERCENTAGE SUM OF THE WI THDR AWAL OF THE OPERATI NG GROUPS.
=
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~
b100 125 8
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RESTRICTED
=
REGION g 80 w
2
.c g
60
.S PERMISSIBLE S
s OPERATING 2
REGION o
40 20 i
i 50 100 150 200 250 300 Rod Index, ' Withdrawal 0
25 50 75 100 1
1 I
e t
Graup 7 0
25 50 75 100 i
t i
t t
Group 6 25 50 75 100 t
t i
Gr0uu 5 CONTROL R00 GROUP WITH0RAWAL LIMITS FOR 3 AND 2 PUMP OPERATION l
UNIT 2 3.5-8g
- E ste OCONEE NUCLEAR STATION Y
Figure 3.5.'2-28
3 POWER LEVEL,fi 120 RESTRICTED REGION 20.4
+5 100 --
80 __
-31 61 60 __
61 -
+24 40 -_
PERMISSIBLE OPERATING REGION 20 _ _
l l
l l
-40 20 0
20 40 Core imbalance.fs OPERATIONAL POWER lMBALANCE ENVELOPE 1
( g UNIT 1 ount.rowen OCONEE NUCLEAR STATION 3.5-8h Figure 3.5.2-3A
m POWER LEVEL, f,
RESTRICTED REGION
-20.4
+6.1
~~100
__ 80 4
-29 61
__60 61
+22 PERMISSIBLE OPERATING REGION 40
_20 40 20 0
+20
+40 Care imbalance, ",
OPERATIONAL POWER IMBALANCE ENVELOPE UNIT 2 3.5-81 (ouu r' win OCONEE NUCLEAR STATION o
M Figure 3.5.2-3B
)
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14 l
12 0
2 4
6 8
10 12 Axial Location From Bottom Of Core,Ft; l
LOCA LIMITED MAXIMUM ALLOWABLE LINEAR HEAT RATE 3.5-83
'sY. OCONEE NUCLEAR STATION at rom Figure 3.5.2-4