ML20204E723

Proposed Tech Specs Clarifying Time Constants for Overtemp Delta T & Overpower Delta T Equations for Table 2.2-1

ML20204E723
Person / Time
Site:	Beaver Valley
Issue date:	07/25/1986
From:	DUQUESNE LIGHT CO.
To:
Shared Package
ML20204E592	List: ML20204E587 ML20204E594 ML20204E723
References
NUDOCS 8608010217
Download: ML20204E723 (4)

Text

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ATTACHMENT A Revise the Technical Specifications as follows:

Remove Pages Insert Pages 2-8 2-8 9

2-10 2-10 i

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TABLE 2.2-1 (CONTINUED) -

m '

4 REACTOR TRIP SYSTEM INSTRUMENTATION TRIP SETPOINTS E NOTATION Q . . - -

I NOTE 1: Overtemperature AT[ l 1 ATo K1 -K2 [1+t,S) 1 + K 3 (P-P') -f(AI) g \1+T4 S}/ .

\ 1+T2

_S

/ -

T[l+T5

\ S/ 3-T' M ~

e . .

s where: ATO

= Indicated AT at RATED THERMAL POWER T = AverageJtemperature, *F y T' = 576.3*F (indicated Tavg at RATED THERMAL POWER) m '

O P = Pressurizer pressure, psig O

g P' = 2235 psig (indicated RCS nominal operating pressure)

@* 1+T1 S = The function generated by the lead-lag controller for Tavg dynamic g 1+T2S compensation.

H

@ T1 & T2 = Time constants utilized in the lead-lag controller for Tavg T1 = 30 secs, T2 = 4 secs.

1 = Lag compensator on measured AT 1+T4S

= Time constant utilized in the lag compensator for AT, 1 2 secs.

14 l 1 = Lag compensator on measured T avg 1+TSS

= Time constant utilized in the lag compensator for Tavg i 2 secs.

T5 l i S = Laplace transform operator.

TABLE 2.2-1 (CONTINUED)

• to

$ REACTOR TRIP SYSTEM INSTRUMENTATION TRIP SETPOINTS .

is -

28 NOTATION h

L-*

! yNOT3 2: Overtemperature AT( 1 1 ATo K 4 -K t3S T( 1 S )T-K6 'Y 1 )-T" -f(AI) i i

.< \1+t 4 -

5(1+t3

\ S/ \l+TS / \l+T5S/ - -

C l 3where: ATO

= Indicated AT at RATED THERMAL POWER e -

g T = Average temperature, 'F T" = Indicated Tavg at RATED THERMAL POWER 1 576.3*F K4

= 1.07 m

@ KS

= 0.02/*F for increasing average temperature en T

& K6

= 0.00128 for T > T"; K6 = (0) for T < T" ~

i co l g tas = The function generated by the rate lag controller for Tavg dynamic

! s 1+t3S compensation.

i z

! O T3

= Time constant utilized in the rate lag controller for Tavg, -t = 10 secs.

1 = Lag compensator on measured AT l 1+t4S t4 = Time constant utilized in the lag compensator for AT,12 secs. l

1 = Lag compensator on measured Tavg

] 1+tSS

= Time constant utilized in the lag compensator for Tavg i 2 secs.

l t5 l S = Laplace transform operator.

f(a) = 0 for all AI I

NOTE 3: The channel's maximum trip point shall not exceed its computed trip point by more than 4 percent.

i

l ATTACHMENT B l Proposed Technical Specification Change No. 116, Revision 1 No Significant Hazards Consideration Description of amendment request: Change Request No. 116 Revision 1 would revise our previous submittal to clarify the time constants utilized in the lag compensator of the overtemperature AT and overpower AT equations of Table 2.2-1 for AT and Tavg.

Basis for no significant hazard determination: Based on the criteria for determining whether a significant hazards consideration exists as setforth in 10 CFR 50.92(c), plant operation in accordance with the proposed amendment would not:

(1) Involve a significant increase in the probability of occurrence or the consequences of an accident previously evaluated because: Our previous submittal specified selection of the t4 and t5 time constants utilized in the lag compensator for the overtemperature AT and overpower AT reactor trip response time at values less than the time set forth in Table 3.3-2. This proposed revision provides clarification of those time constants by specifying an upper limit of 2 seconds for t4 and 15. This will ensure that the RTD t values do not affect the overtemperature AT and overpower AT allowable values provided the maximum allowable overall channel response time criteria is not exceeded.

(2) Create the possibility of a new or different kind of accident from any previously evaluated since the lag compensation for the AT and Tavg circuits will be accounted for in the equations and the overtemperature AT response time reflects the safety analysis assumptions.

(3) Involve a significant reduction in the margin of safety since an upper limit of 2 seconds is specified for the 14 and t5 5 ime t constants to provide additional assurance that the overall channel response time will not be exceeded and the OTAT and OPAT allowable values will not be affected by the RTD t values.- ,

Conclusion The proposed changes clarify the t4 and t5 time constants used in the overtemperature AT and overpower AT equations of Table 2.2-1. These changes will not increase the likelihood of a malfunction of safety-related equipment, increase the consequences of an accident previously analyzed, nor create the possibility of a malfunction different than previously evaluated. Therefore, based on the above, it is proposed to characterize the change as involving no significant hazards consideration.