ML20052H284

Proposed Tech Spec Changes Re RTD Response Time

ML20052H284
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/03/1982
From:	ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML20052H281	List: ML20052H280 ML20052H284
References
NUDOCS 8205200137
Download: ML20052H284 (5)

Text

. 1 g .

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g TABLE 3.3-2 (Continued)

@N3 REACTOR PROTECTIVE INSTRUMENTATION RESPONSE TIMES 88 FUNCTIONAL UNIT RESPONSE TIME

> 10. DNBR - Low

, a. Neutron Flux Power from Excore Neutron Detectors 5,0.39 seconds *

b. CEA Positions < 1.09 seconds **

, c. Cold Leg Temperature 53.79 seconds ##

5 d. Hot Leg Temperature < 1.54 seconds ##

F, e. Primary Coolant Pump Shaft Speed 50.80 seconds #

a f. Reactor Coolant Pressure from Pressurizer ~< 3.19 seconds

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11. Steam Generator Level - High Not Applicable

[

• Neutron detectors are exempt from response time testing. Response time of the neutron flux signal portion of the channel shall be measured from detector output or input of first electronic component in channel.

• • Response time shall be measured from the onset of a single CEA drop.

$ # Response time shall be measured from the onset of a 2 out of 4 Reactor Coolant Pump coastdown.

1. 1. Based on a resistance temperature detector (RTD) response time of < 6.0 seconds where the RTD S'

response time is equivalent to the time interval required for the RTD output to achieve 63.2%

of its total change when subjected to a step change in RTD temperature.

N~* If the effective RTD time constant for a CPC channel exceeds 6.0 seconds, the DNBR and LPD penalties for the affected channel (s) shall be increased by the amount indicated on Figure 3.3-1, and the Power Operating Limit on DNB will be decreased by the amount shown in Table 3.3-3.

TABLE 3.3-3 DNBR POWER OPERATING LIMIT ADJUSTMENTS Effective RTD Time Constant Penalty (Seconds) (% Power) 1 6.0 0 6.0 < t 1 8.0 4 8.0 < 1 1 10.0 5

10. 0 < t i 13. 0 9

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3/4.3 INSTRUMENTATION BASES 3/4.3.1 and 3/4.3.2 PROTECTIVE AND ENGINEERED SAFETY FEATURES (ESF)

INSTRUMENTATION The OPERABILITY of the protective and ESF ~ ~ wmentation systems and bypasses ensure that 1) the associated ESF a u ._.. and/or reactor trip will be initiated when the parameter monitored by each channel or combination thereof reaches its setpoint, 2) the specified coincidence logic is maintained, 3) sufficient redundancy is maintained to permit a channel to be out of service for testing or maintenance, and

4) sufficient system functional capability is available for protective and ESF purposes from diverse parameters.

The OPERABILITY of these systems is required to provide the overall reliability, redundancy and diversity assumed available in the facility d9 sign for the protection and mitigation of accident and transient conditions. The integrated operation of each of these systems is consistent with the assumptions used in the accident analyses.

The surveillance requirements specified for these systems ensure that the overall system functional capability is maintained comparable to the original design standards. The periodic surveillance tests performed at the minimum frequencies are sufficient to demonstrate this capability.

The measurement of response time at the specified frequencies provides assurance that the protective and ESF action function associated with each channel is completed within the time limit assumed in the accident analyses. No credit was taken in the analyses for those channels with response times indicated as not applicable.

Response time may be demonstrated by any series of sequential, overlapping or total channel test measurements provided that such tests demonstrate the total channel response time as defined. Sensor response time verification may be demonstrated by either 1) in place, onsite or offsite test measurements or 2) utilizing replacement sensors with certified response times.

The RTD response time for the Core Protection Calculator System (CPCS) is expressed as an effective time constant. The effective time constant is determined based on the utilization within the CPCS calculations. For hot leg temperatures, the effective time constant to be used in Figure 3.3-1 for a given CPC channel is determined from the mean time constant for averaged pairs of hot leg RTD inputs to the channel. This is done because the CPCS utilizes the mean hot leg temperature in its DNBR and LPD calculations. For cold leg temperatures, the effective time constant to be used in Figure 3.3-1 may be considered to be the smaller time constant of the two cold leg RTD inputs for a given channel. This is due to the fact that the CPC utilizes either the maximum cold leg temperature B 3/4 3-1

.o or the minimum cold leg temperature in its various DNBR and LPD calculations for conservatism. However, for. asymmetric steam generator

, protection, the maximum time constant of the two cold leg RTDS input to a given channel must be used in Table 3.3-3 since the CPC utilizes both cold leg RTD inputs in this calculation.

3/4.3.3 MONITORING INSTRUMENTATION 3/4.3.3.1 RADIATION MONITORING INSTRUMENTATION The OPERABILITY of the radiation monitoring channels ensures that

1) the radiation levels are continually measured in the areas served ARKANSAS - UNIT 2 B 3/4 3-la

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