Text

Proposed Tech Specs Re Quadrant Power Tilt Ratio
	ML20082F461
Person / Time
Site:	North Anna
Issue date:	11/18/1983
From:	; VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	;
Shared Package
ML20082F459	List: ML20082F456; ML20082F461;
References
	NUDOCS 8311290047
	Download: ML20082F461 (14)
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POWER DISTRIBUTION Lb ?S QUADRANT POWER TILT RATIO LIMITING CONDITION FOR OPERATION 3.2.4 THE QUADRANT POWER TILT RATIO shall not exceed 1.02.

APPLICABILITY: MODE 1 above 50% of RATED THERMAL POWER

ACTION:

a.

With the QUADRANT POWER TILT RATIO determined to exceed 1.02 but s 1.09:

1.

Within 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months s:

a) Either reduce the QUADRANT POWER TILT RATIO to within its limit, or b) Reduce THERMAL POWER at least 3% from RATED THERMAL POWER for each 1% of indicated QUADRANT POWER TILT RATIO in excess of 1.0 and similarly reduce the Power Range Neutron Flux-High Trip Setpoints within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

2.

If during the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after the QUADRANT POWER TILT RATIO exceeds 1.02, Action Statement a.1.b has been implemented and the hot channel factors have been determined using a full-core flux nap, then the power level and Power Range Neutron Flux-High Trip Setpoints may be adjusted based on the analysis of the full core flux map to ensure compliance with Specifications 3.2.2 and 3.2.3.

Any power level increase resulting from flux-map verification of compliance with the hot channel factor specifications will supersede the power level reduction implemented by Action Statement a.1.b.

Twenty-four (24) hours after identification of the Quadrant Power Tilt Ratio exceeding 1.02 Action Station a.3 must be complied with.

3.

Verify that the QUADRANT POWER TILT RATIO is within its limit l within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after exceeding the limit or reduce THERMAL POWER to less than 50% of RATED THERMAL POWER within the next 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and reduce the Power Range Neutron Flux-High Trip Setpoints to s 55% of RATED THERMAL POWER within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

4.

Identify and correct the cause of the out of limit condition l

prior to increasing THERMAL POWER; subsequent POWER OPERATION above 50% of RATED THERMAL POWER may proceed provided that the QUADRANT POWER TILT RATIO is verified within its limit at least once per hour for 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months or until verified acceptable at 95% or greater RATED THERMAL POWER.

See Special Test Exception 3.10.2 i

8311290047 831118 PDR ADOCK 05000338 p

PDR NORTH ANNA - UNIT 1 3/4 2-12 j.

POWER DISTRIBUTION LIMITS QUADRANT POWER TILT RATIO LIMITING CONDITION FOR OPERATION (Continued b.

With the QUADRANT POWER TILT RATIO determined to exceed 1.09 due to misalignment of either a shutdown or control rod:

1.

Reduce THERMAL POWER at least 3% from RATED THERMAL POWER for each 1% of indicated QUADRANT POWER TILT RATIO in excess of 1.0, within 30 minutes.

2.

Verify that the QUADRANT POWER TILT RATIO is within its limit within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months after exceeding the limit or reduce THERMAL POWER to less than 50% of RATED THEREL POWER within the next 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and reduce the Power Range Neutron Flux-High Trip Setpoints to less than or equal to 555% of RATED THERMAL POWER within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

3.

Identify and correct the cause of the out of limit condition prior to increasing THERMAL POWER; subsequent POWER OPERATION above 50% of RATED THERMAL POWER may proceed provided that the QUADRANT POWER TILT RATIO is verified within its limit at least once per hour for 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months or until verified acceptable at 95% or greater RATED THERMAL POWER.

c.

With the QUADRANT POWER TILT RATIO determined to exceed 1.09 due to causes other than the misalignment of either a shutdown or control rod:

1.

Reduce THERMAL POWER to less than 50% af RATED THERMAL POWER within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and reduce the Power Range Neutron Flux-High Trip Setpoints to less than or equal to 555% of RATED THERMAL POWER within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

2.

Identify and correct the cause of the out of limit condition prior to increasing THERMAL POWER; subsequent POWER OPERATION above 50% of RATED THERMAL POWER may proceed provided that the QUADRANT POWER TILT RATIO is verified within its limit at least once per hour for 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months or until verified at 95% or greater RATED THERMAL POWER.

SURVEILLANCE PEQUIREMENTS 4.2.4.1 The QUADRANT POWER TILT RATIO shall be determined to be within the limit above 50% of RATED THERMAL POWER by:

a.

Calculating the racia at least once per 7 days when the alarm is OPERABLE.

b.

Calculating the ratio at least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months during steady state operation when the alarm is inoperable.

NORTH ANNA - UNIT 1 3/4 2-13

1 POWER DISTRIBUTION LIMITING CONDITION FOR OPERATION (CONTINUED) 4.2.4.2 The QUADRANT POWER TILT RATIO shall be determined to be within the limit when above 75 percent of RATED THERMAL POWER with one Power Range Channel inoperable by using the movable incore detectors to confirm that the normalized symmetric power distribution, obtained from 2 sets of 4 pairs of symmetric thimble locations or a full-core flux map, is consistent with the indicated QUADRANT POWER TILT RATIO at least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

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NORTH ANNA - UNIT 1 3/4 2-14

POWER DISTRIBUTION LIMITS DNB PARAMETERS LIMITING CONDITION FOR OPERATION (Continued) 3.2.5 The following DNB related parameters shall be maintained within the i

limits shown on Table 3.2-1:

Reactor Coolant System T,yg a.

b.

Pressurizer Pressure c.

Reactor Coolant System Total Flow Rate APPLICABILITY: MODE 1 ACTION:

With any of the above parameters exceeding its limit, restore the parameter to within its limit within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months or reduce THERMAL POWER to less than 5% of RATED THERMAL POWER within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

SURVEILLANCE REQUIREMENTS 4.2.5.1 Each of the parameters of Table 3.2-1 shall be verified to be within their limits at least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

4.2.5.2 The Reactor Coolant System total flow rate shall be determined to be within its limit by measurement at least once per 18 months.

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l NORTH ANNA - UNIT 1 3/4 2-15 l

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TABLE 3.2-1 DNB PARAMETERS 2

O M

LIMITS 2 Loops In Operation **

2 Loops In Operation **

I 3 Loops In

& Loop Stop

& Isolated Loop PARAMETER Operation Valves Open Stop Valves Closed U

~

5587*F Reactor Coolant System T, pressurizer Pressure 22205 psig*

Reactor Coolant System 2278,400 gpm Total Flow Rate t

U z~

Y E

Limit not applicable during either a THERMAL POWER ramp increase in excess of 5% RATED THERMAL POWER per minute or a THERMAL POWER step increase in excess of 10% RATED THERMAL POWER.

- Values dependent on NRC approval of ECCS evaluation for these conditions.

POWER DISTRIBUTION LIMITS AXIAL POWER DISTRIBUTION LIMITING CONDITION FOR OPERATION 3.2.6 The axial power distribution shall be limited by the following relationship:

l

[F (Z)]g = (R )(P )(1.03)(1 + o})(1.07)

Where:

a.

F (Z) is the normalized axial power distribution from thimble 3

j at core elevation Z.

b.

P is the fraction of RATED THERMAL POWER.

c.

K(Z) is the function obtained from Figure 3.2-2 for a given core height location, d.

R, for thimble j, is determined from at least n=6 incore flux maps covering the full configuration of permissible rod patterns above P % of RATED THERMAL POWER in accordance with:

n j

ij i=1 Where:

0 R

=

ij

[F (Z)] Max and [Fg(Z)]g is the maximum value of the normalized axial distribution at elevation Z from thimble j in map i which had a measured peaking factor without uncertainties eas or densification allowance of NORTH ANNA - UNIT 1 3/4 2-17 l

POWER DISTRIBUTION LIMITS LIMITING CONDITION FOR OPERATION (Continued) e.

6 is the standard deviation associated with thimble j, expressed as a fraction or percentage of R, and is derived from n flux maps from the relationship below, or 0.02, (2%) whichever is greater.

n II n-1[=1(Rj ij)

-R d

=

j ij f.

The factor 1.07 is comprised of 1.02 and 1.05 to account for the axial power distribution instrumentation accuracy and the measure-ment uncertainty associated with F using the movable detector q

system, respectively.

g.

The factor 1.03 is the engineering uncertainty factor.

APPLICABILITY: MODE 1 AB0VE P % OF RATED THERMAL POWER', where the value for P is establisEed in the Core Surveillance Report per Technical Specification 6.9.1.10.

ACTION:

a.

With a F (Z) factor exceeding [F (Z)] 3 by less than or equal to 4 percent, reduce THERMAL POWER one percent for every percent by which the F (Z) factor exceeds its limit within 15 minutes and within the l

next two hours either reduce the F (Z) factor to within its limit 3

or reduce THERMAL POWER to P,% or less of RATED THERMAL POWER.

b.

With a F (Z) factor exceeding [F (Z)] g by greater than 4 percent, reduce THERMAL POWER to P,% or less of RATED THERMAL POWER within 15 minutes.

l

The APDMS may be out of service when surveillance for determining power distribution maps is being performed.

NORTH ANNA - UNIT 1 3/4 2-18 l

POWER DISTRIBUTION LIMITS SURVEILLANCE REQUIREMENTS 4.2.6.1 F)(Z) shall be determined to be within its limit by:

a.

Either using the APDMS to monitor the thimbles required per Specification 3.3.3.8 at the following frequencies.

1.

At least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , and 2.

Immediately and at intervals of 10, 30, 60, 90, 120, 240 and 480 minutes following:

a) Increasing the THERMAL POWER above P % of RATED THERMAL POWER, or b) Movement of control bank "D" more than an accumulated total of 5 steps in any one direction.

b.

Or using the movable incore detectors at the following fre-quencies when the APDMS is inoperable:

1.

At least once per 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , and 2.

At intervals of 30, 60, 90, 120, 240 and 480 minutes following:

a)

Increasing the THERMAL POWER above P % of RATED THERMAL POWER, or b) Movement of control bank "D" more than an accumulated total of 5 steps in any one direction.

4.2.6.2 When the movable incore detectors are used to monitor F (Z), at least 2 thimbles shall be monitored and an F (Z) accuracy equivalent to that 3

obtained from the APDMS shall be maintained.

NORTH ANNA - UNIT 1 3/4 2-19

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POWER DISTRIBUTION LIMITS QUADRANT POWER TILT RATIO LIMITING CONDITION FOR OPERATION i

3.2.4

_THE QUADRANT POWER TILT RATIO shall not exceed 1.02.

f APPLICABILITY:

MODE I above 50% of RATED THERMAL POWER

J.

ACTION:

a.

With the QUADRANT POWER TILT-RATIO determined to exceed 1.02 but less than or equal to 1.09:

1.

Within 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months s:

l a) Either reduce the QUADRANT POWER TILT RATIO to within its limit, or e

b) Reduce THERMAL POWER at least 3% from RATED THERMAL POWER for each 1% of indicated QUADRANT POWER TILT RATIO in excess of 1.0 and similarly reduce the Power Range l

Nertron Flux-High Trip Setpoints within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

i 2.

If during the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after the QUADRANT POWER TILT RATIO exceeds 1.02, Action Statement a.1.b has been implemented and the hot channel factors have been determined using a full-core flux map, then the power level and Power Range Neutron Flux-High Trip l

Setpoints may be adjusted based on the analysis of the full core l

flux map to ensure compliance with Specifications 3.2.2 and 3.2.3.

Any power level increase resulting from flux-map verifica-tion of compliance with the hot channel factor specifications I

will supersede the power level reduction implemented by Action Statement a.1.b.

Twenty-four (24) hours after identification of the Quadrant Power Tilt Ratio exceeding 1.02 Action Statement a.3 must be complied with.

3.

Verify that the QUADRANT POWER TILT RATIO is within its limit l within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after exceeding the limit or reduce THERMAL POWER to less than 50% of RATED THERMAL POWER within the next 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and reduce the Power Range Neutron Flux-High Trip Setpoints to l

1ess than or equal to 55% of RATED THERMAL POWER within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

4.

Identify and correct the cause of the out of limit condition 3

l prior to increasing THERMAL POWER; subsequent POWER OPERATION above 50% of RATED THERMAL POWER may proceed provided that the QUADRANT POWER TILT RATIO is verified within its limit at least once per hour for 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months or until verified acceptable at 95% or greater RATED THERMAL POWER.

See Special Test Exception 3.10.2 i

NORTH ANNA - UNIT 2 3/4 2-12 t

POWER DISTRIBUTION LIMITING CONDITION FOR OPERATION (Continued) 4 I

b.

With the QUADRANT POWER TILT RATIO determined to exceed 1.09 due to misalignment of either a shutdown or control rod:

1.

Reduce THERMAL POWER at least 3% from RATED THERMAL POWER for l each 1% of indicated QUADRANT POWER TILT RATIO in excess of 1.0, within 30 minutes.

2.

Verify that the QUADRANT POWER TILT RATIO is within its limit l within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months after exceeding the limit or reduce THERMAL POWER to less than 50% of RATED THERMAL POWER within the next 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and reduce the Power Range Neutron Flux-High Trip Setpoints to less than or equal to 55% of RATED THERMAL POWER within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

3.

Identify and correct the cause of the out of limit condition l prior to increasing THERMAL POWER; subsequent POWER OPERATION above 50% of RATED THERMAL POWER may proceed provided that the QUADRANT POWER TILT RATIO is verified within its limit at least once per hour for 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months or until verified acceptable at 95% or greater RATED THERMAL POWER.

c.

With the QUADRANT POWER TILT RATIO determined to exceed 1.09 due to causes other than the misalignment of'either a shutdown or control rod:

1.

Reduce THERMAL POWER to less than 50% of RATED THERMAL POWER within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and reduce the Power Range Neutron Flux-High Trip Setpoints to less than or equal to 55% of RATED THERMAL POWER within the next 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

2.

Identify and correct the cause of the out of limit condition prior to increasing THERMAL POWER: subsequent POWER OPERATION above 50% of RATED THERMAL POWER may proceed provided that the QUADRANT POWER TILT RATIO is verified within its limit at least once per hour for 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months or until verified at 95% or greater RATED THERMAL POWER.

SURVEILLANCE REQUIREMENTS l

4.2.4.1 The QUADRANT POWER TILT RATIO shall be determined to be within the limit above 50% of RATED THERMAL POWER by:

l a.

Calculating the ratio at least once per 7 days when the alarm is l

OPERABLE.

b.

Calculating the ratio at least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months during steady state operation when the alarm is inoperable.

l l

f NORTH ANNA - UNIT 2 3/4 2-13 1.

SURVEILLANCE REQUIREMENTS 4.2.4.2 The QUADRANT POWER TILT RATIO shall be determined to be within the limit when above 75 percent of RATED THERMAL POWER with one Power Range Channel inoperable by using the movable incore detectors to confirm that the normalized symmetric power distribution, obtained from 2 sets of 4 pairs of symmetric thimble locations or a full-core flux wap, is consistent with the indicated QUADRANT POWER TILT RATIO at least once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

p l

l l

NORTH ANNA - UNIT 2 3/4 2-14

O e

ATTACHMENT 3

DISCUSSION OF PROPOSED TECHNICAL SPECIFICATION CHANCES The purpose of the power reduction currently included in Specification 3.2.4 as a requirement, when the quadrant power tilt ratio exceeds 1.02, is to provide linear heat rate and DNBR protection for the reactor fuel. However, the reduction of 3 percent reactor power for each 1% by which quadrant tilt exceeds its limit, could provide excessive margin between the actual hot channel factor values, and the limits identified in Specifications 3.2.2 and 3.2.3.

The additional provision to perform full-core flux mapping in order to measure the explicit values for the F and F hot channel factors, will identify the margin 9

AH available with respect to the Technical Specifications limits for these hot channel factors.

Identification of this margin will allow subsequent power increases, to maximize power production capability, without eliminating the necessary linear heat rate and DNBR protection.

The allowable flux mapping and power level adjustment would be applicable only during the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after the quadrant power tilt ratio exceeds 1.02.

If the quadrant tilt cannot be returned within its limit within the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , then the power reduction to 50% power would be required.

For North Anna Unit 2, the requirement for hourly quadrant power tilt calculations is extraneous and is not necessary in order to ensure linear heat rate and DNBR protection. The 3 percent power reduction for each 1 percent of quadrant tilt, and subsequent reduction to 50% power if the tilt limit is not met, provides the necessary reactor core protection without need for hourly tilt monitoring.

Neither of these changes adversely affects the safe operation of the plant. The probability of occurrence, or the consequences of an accident or malfunction of equipment important to safety, previously evaluated in the safety analysis report is not increased, the possibility for an accident or malfunction of a different type than any evaluated previously in the safety analysis report is not created, and the margin to safety as defined in the Technical Specifications basis is not reduced. These changes do not involve a significant safety hazards consideration.

_.- _-..-.

ML20082F461

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