ML19317D227

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Proposed Tech Spec 3.5 Incorporating Control Rod Position & Axial Imbalance Limits to Period After 100 Plus or Minus 10 Effective Full Power Days
ML19317D227
Person / Time
Site: Oconee  Duke Energy icon.png
Issue date: 01/23/1978
From:
DUKE POWER CO.
To:
Shared Package
ML19317D226 List:
References
NUDOCS 7911190613
Download: ML19317D227 (14)


Text

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ATTACINENT 1 OCONEE 1, CYCLE 4 PROPOSED TECHNICAL SPECIFICATION CHANGES 591119o(/ 3

. ("i (3) Except cs pr vid:d in specificaticn 3 5.2.4.b, th) rccctor shall be brought to the hot shutdown condition within four hours if the quadrant power tilt is not reduced to less than 6.03% Unit I within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

3.41% Unit 2 3.41% Unit 3

b. If the quadrant tilt exceeds +6.03% Unit I and there is simultaneous 3.41% Unit 2 3.41% Unit 3 indication of a misaligned control rod per Specification 3.5.2.2, reactor operation a.ay continue provided power is reduced to 60%

of the thermal power allowable for the reactor coolant pump combination.

c. Except for physics test, if quadrant tilt exceeds 9.44% Unit 1, 9.44% Unit 2 9.44% Unit 3 a controlled shutdown shall be initiated immediately, and the reactor shall be brought to the hot shutdown condition within four hours.
d. u<,ever the reactor is brought to hot shutdown pursuant to 3 5.2.4.a(3) or 3.5.2.4.c above, subsequent reactor operation is permitted for the purpose of measurement, testing, and corrective action provided the thermal power and the power range high flux setpoint allowable for the reactor coolant pump combination are restricted by a reduction of 2 percent of full power for each I percent tilt for the maximum tilt observed prior to shutdown.
e. Quadrant power tilt shall be monitored on a minimum frequency of once every two hours during power operation above 15 percent of rated power.

3.5.2.5 Control Rod Positions

a. Technical Specification 3.1.3.5 does not prohibit the exercising of individual safety rods as required by Table 4.1-2 or apply to inoperable safety rod limits in Technical Specification 3 5.2.2.
b. Except for physics tests, operating rod group overlap shall be 25% + 5% between two sequential groups. If this limit is exceeded, corrective measures shall be taken immediately to achieve an accep-table overlap. Acceptable overlap shall be attained within two hours or the reactor shall be placed in a hot shutdown condition within an additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />,
c. Position limits are specified for regulating and axial power shaping control rods. Except for physics tests or exercising control rods, the regulating control rod insertion / withdrawal  ;

limits are specified on figures 3 5.2-1A1 and 3.5.2-1A2 I (Unit 1); 3.5.2-181, .t.5.2-182 and 3 5.2-1B3 (Unit 2);

3.5.2-Ici, 3.5.2-Ic2 and 3.5 2-Ic3 (Unit 3) for four pump operation, and on figures 3.5.2-2Al and 3.5.2-2A2 l (Unit 1): 3 5 3-2B1, 3.5.2-282 and 3.5.2-283 (Unit 2):

3 5 2-2ci, 3.5 2-2c2 and 3 5 2-2c3 (Unit 3) for two or three 3.5-8 A 53/53/50 11/23/77

,n.

pump opero..an. Als3, excepting physics tcs.., er ex3rcising c:ntrol rods, tha cxial power sh: ping control rod Ins 2rtien/

withdrawal limits are specified on figures 3.5.2-4Al, and

. 3.5.2-4A2 (Unit 1); 3.5.2-4B1, 3.5.2-482, and 3 s5.2-4a3 (Uni t 2).,  !

If the control rod position limits are exceeded, corrective measures shall be taken immediately to achleye an acceptable control rod position. An acceptable control rod position shall then be attained within two hours. The minimum shutdown margin required by Specification 3.5.2.1 shall be maintained at all times.

d. Except for physics tests, power shall not be increased above the power level cutoff as shown on Figures 3 5 2-1A1, and 3.5.2-1 A2 l (Unit 1), 3.5.2-1B1, 3.5.2-1B2, and 3.5.2-1B3 (unit 2), and 3.5.2-Ici, 3.5.2-Ic2, 3.5.2-Ic3 (Unit 3), unless the following requirements are met.

(1) The xenon reactivity shall be within 10 percent of the value for operation at steady-state rated power.

(2) The xenon reactivity worth has passed its final maximum or minimum peak during its approach to its equilibrium valve for operation at the power level cutoff.

3 5.2.6 Reactor power imbalance shall be monitored on a frequency not to exceed two hours during power operation above 40 percent rated power.

Except for physics tests, Imbalance shall be maintained within the envelope defined by Figures 3.5.2-3A1, 3 5 2-3B1, 3.5 2-382, 3 5 2-3B3, 3.5.2-3ci, 3.5.2-3c2, and 3 5.2-3C3 If the imbalance is not within the envelope defined by these figures, corrective measures shall be taken to achieve an acceptable imbalance. If an acceptable imbalance is not achieved within two 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 manager or his designated alternate.

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3 5-9

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Bases s -

. Th2 power-imbalcnco cnvalepa dafin d in Figurcs 3.5.2-3Al, l 3.5.'2-381, 3 5 2-3B2, 3.5.2-383, 3.5.2-3C1, 3 5 2-3C2 and 3 5 2-3C3 is based on LOCA analyses which have defined the maximum linear heat rate (see Figure 3.5.2-5) such that the maximum clad temperature will not exceed the Final Acceptance Criteria. Corrective measures will be taken immediately should the Indicated quadrant tilt, rod position, or imbalance be outside their specified boundary. Operation in a situation that would cause the Final Acceptance Criteria to be approached should a LOCA occur is highly improbable because all of the power distribution 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 power spike factors (Units 1 and 2 only)
d. Hot rod manufacturing tolerance factors
e. Fuel rod bowing power spike factors The 25% + 5% 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:

Group Function 1 Safety 2 Safety 3 Safety 4 Safety 5 Regulating 6 Regulating 7 Xenon transient override 8 APSR (axial power shaping bank)

The rod position Iimits are based on the most 1imitIng of the following three criteria: ECCS power peaking, shutdown margin, and potential ejected rod worth.

Therefore, compliance with the ECCS power peaking criterion is ensured by the rod position limits. The minimum available rod worth, consistent with the rod l

position limits, provides for achieving hot shutdown by reactor trip at any l time, assuming the highest worth control rod that is withdrawn remains in the full l out position (1). The rod position 1imits also ensure that inserted rod groues will not contain single rod worths greater than 0.65%

ak/k at rated power. These values have been shown to be safe by the safety analysis (2,3,4,5) of hypothetical rod ejection accident. A maximum single inserted control rod worth of 1.0%Ak/k is allowed by the rod position limits at hot zero power. A single inserted control rod worth of 1.0% ak/k at beginning-of-life, hot zero power would result in a lower transient peak thermal power and, therefore, less severe environmental consequences than a 0.65% ak/k ejected rod worth at rated power.

    • Actual operating limits depend on whether or nct incore or excore detectors l are used and their respective instrument calibration errors. The method used l to define the operating limits is defined in plant operating procedures.

3.5-10

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- Control rod groups are withdrawn in sequenca beginning with Grcup 1.

Groups 5, 6, and 7 are overlapped 25 percent. The normal position at power is for Groups 6 and 7 to be partially inserted.

The quadrant power tilt limits set forth in Specification 3 5.2.4 have been estabilshed to prevent the linear heat rate peaking increase associated with a positive quadrant power tilt during normal power operation from exceeding 9.00% for Unit 1. The limits shown in Specification 3 5 2.4 l 5.10% for Unit 2 5.10% for Unit 3 are measurement system independent. The actual operating limits, with the appropriate allowance for observability and instrumentation errors, for each measurement system are defined in the station operating procedures.

The quadrant tilt and axial imbalance monitoring in Specification 3.5.2.4 and 3.5.2.6, respectively, normally will be performed in the process computer.

The two-hour frequency for monitoring these quantitles will provide adequate surveillance when the compute- Is out of service.

Allowance is provided for* withdrawal limits and reactor power imbalance limits to be exceeded for a period of two hours without specification vic' tion. Acceptable rod positions and imbalance must be achieved within the two-hour time period or appropriate action such as a reduction of power taken.

Operating restrictions are included in Technical Specification 3 5 2 5d to prevent excessive power peaking by transient xenon. The xenon reactivity must be beyond its final maxir.ium or minimum peak and approaching its equill-brium valu2 at the power level cutoff.

REFERENCES FSAR, Section 3 2.2.1.2 FSAR, Section 14.2.2.2 FSAR, SUPPLEMENT 9

%W FUEL DENSIFICATION REPORT BAW-1409 (UNIT 1)

BAW-1396 (UNIT 2)

BAW-1400 (UNIT 3) 5 0conee 1, Cycle 4 - Reload Report - BAW-1447, March 1977, Section 7.11 l

l 3.5-11

j (2T4,102)

(253,102) e ' (300,102)

OPERATION IN THIS REGION go IS NOT ALLOWED

_ (274,9 0)'

MINIMUM  !

00 -

(265,80) POWER SHUTDOWN LEVEL

$ LIMIT CUTOFF 2 TO -

OPER ATION IN g THIS REGION 60 -

IS RESTRICTED (266,60) 8 50 (Iso,sO) g 4'O -

5 c.

30 - PERMISSIBLE OPERATING REGION 20 -

(1l0,15) 10 -

(64,0) t I f I f f O 60~ 10 0 14 0 18 0 220 260 300 ROD INDEX, */o WITHDRAWN OCONEE 1 CYCLE 4 ROD POSITIO!.

LIMITS FOR FOUR PUMP OPERATION AFTER 100 + 10 EFPD

\ OCONEE NUCLEAR STATION

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Figure 3.5.2-1A2 3.5-13

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3.5-13a i

' * ,10 2) 40 0 gg o

. OPERATION IN THIS REGION IS NOT ALLOWED WITH 3 Puur to - 2 M3 PWPS mest c (252,80) la Tres a- maso a so -

8

~

II '50 ) (172, 50)

E g 40 -

d PERMISSIBLE

< 30 -

8 OPERATING REGION g 20 -

- (110 ,85 )

g 10 -

2 (64,0) 0 10 0 14 0 ISO 220 260 500 ROD INDEX,*/o WITHDRAWN OCONEE 1 CYCLE 4 R00 POSITION LIMITS FOR TWO AND THREE PUMP OPERATION AFTER 100 + 10 EFPD

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. OCONEE NUCLEAR STATION Figure 3.5.2-2A2 3.5-18a

.(. _ _ _

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3.5-18b

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POWER, 5 of 2568 NWt RESTRICTED REGION 110 --

( 17.3.102) igg _ _ , (9.0.102)

(8.8,90)

( 15.3,90) 30 80 70 PERMISSIBLE OPERATING 60 RANGE 50 40 30 20 10 I I O l l

-20 -10 0 +10 +20 Core Imaalance, 2, OPERATIONAL POWER IMSALANCE ENVELOPE, Unit 1 k OCONEE NUCLEAR STATION 3,5-21 W Figure 3.5.2-3Al ,

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ENTIRE PAGE DELETED i

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100 _

("** } i (32.0,102) RESTRICTED REGION 90 - (8.6,90) .

,(34.4,90) 80 - < .(6.2,80) < ,(34.4.80) 70 - (6.1,70) < (34 4.70)

(85.4,60)

" 60 <w (6.1,60) _

m y (0,60) (100,60) 50 PERMISSIBLE f 40 -

OPERATING f REGION

30 20 10 0 l I I I I I l l 1 0 10 20 30 40 50 60 70 80 90 100 APSR, 5 Withdrawn l

l APSR POSITION LIMITS FOR OPERATION AFTER 100 (110)

EFPD, UNIT 1 A

l Jut Man, OCONEE NUCLEAR STATION

3. 5-23d Figure 3.5.2-4A 2 l

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