ML20072C495

Proposed Tech Specs Re High Negative Neutron Flux Rate Trip

ML20072C495
Person / Time
Site:	Comanche Peak
Issue date:	08/09/1994
From:	TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:
Shared Package
ML20072C487	List: ML20072C484 ML20072C495
References
NUDOCS 9408170265
Download: ML20072C495 (4)

Text

. _ _ .

Attachment 3 to TXX-94211 Page 1 of 4 n TABLE 2.R-1

~'jj h REACTOR TRIP SYSTEN INSTRLMENTATION TRIP SETPOINTS 8M

- 2-S TOTAL SENSOR  ;

o [ ALLOWANCE ERROR ks3 y fjE710NAL UNIT fTA) Z fS) TRIP SETPOINT ALLOWABLE VALUE s ur n om

l. Manual Reactor Trty N.A. N.A. N.A. N.A. N.A 8$ E

,@g ] 2. Power Range, Neutron Flux ae g$ ~

a. High Setpoint 7.5 4.56 1.25 s109% of RTP*

s111.7% of RTP*

$E

b. Low Setpoint 8.3 4.56 1.25 s25% of RTP* s27.7 of RTP*

3. Power Range, Neutron Flux, 1.6 0.5 0 s5% of*RTP* with $6.3% of RTP* with High Positive Rate a time constant a time constant 22 seconds 22 seconds

'? 4. ."z:;- t:;;:, " ;tm Fhr, 1.6 9.5 9 s5% ef R"* e!th $6.3 ef RTP =!th" b "ip ".;, .the hta  : tt= c=st=t  : t!= constant /

22 sec =ds 22 seceads t-cc 5. Intermediate Range, 17.0 8.41 0 $25% of RTP* s31.5 of RTP*

Neutron Flux '

c+ n

{ 6. Source Range, Neutron Flux 17.0 10.01. O s105 cps si.4 x 10 5cps i

' g ss

7. Overtemperature M-16

a. Unit 1 10.53 6.70 See Note 1 1.0+g.10+ See Note 2 g b. Unit 2 10.0 6.75 0.76 8 1.0+1.38+ See Note 1 3s

"" See Note 2 0.96can i EE T

L

• RTP = RATED THEkMAL POWER (1) 1.0% span for N-16 power monitor, 1.10% for T,,g, RTDs and 0.765 for pressurizer pressure sensors.

(2) 1.0% sp2n for N-16 power monitor,1.38% for T,,,, RTDs and 0.96% for pressurizer pressure sensors. l' L

_ - _ _ - - . _ _ _ _ _ _ - - . . - _ - . - _ - - - - . - - _ - _ - - _ . - - - - . _ _ . _ - - - - _ _ - - _- - - _ ,a -

o

. A pachment 3 to TXX-94211 Page 2 of 4  ;

l LIMITING SAFETY SYSTEM SETTINGS BASES REACTOR TRIP SYSTEM INSTRUMENTATION SETPOINTS (Continued)

The various Reactor trip circuits automatically open the Reactor trip breakers whenever a condition monitored by the Reactor Trip System reaches a preset or calculated level.

In addition to redundant channels and trains, the design approach provides a Reactor Trip System which monitors numerous system variables, therefore providing Trip System functional diversity. The func-tional capability at the specified trip setting is required for those antici-patory or diverse Reactor trips for which no direct credit was assumed in the safety analysis to enhance the overall reliability of the Reactor Trip System.

The Reactor Trip System inittetes a Turbine trip signal whenever Reactor trip is initiated. This prevents the insertion of positive reactivity that would otherwise result from excessive Reactor Coolant System cooldown and thus avoids i

l unnecessary actuation of the Engineered Safety Features Actuation System.

Manual Reactor Trin 1

The Reactor Trip System includes manual Reactor trip capability.

Power Rance. Neutron Flux -

In each of the Power Range Neutron Flux channels there are two independent bistables, setting. Theeach with its own trip setting used for a High and Low Range trip Low Setpoint trip provides protection during subcritical and low power operations to mitigate the consequences of a power excursion beginning from low power, and the High Setpoint trip provides protection during power operations to mitigate the consequences of a reactivity excursion from all power levels. l The Low Satpoint trip may be manually blocked above P-10 (a power level of approximately 105 of RATED THERMAL POWEP) and is automatically reinstated below the P-10 Setpoint, t Power Ranos. Neutron Flux. Hiah Rates The Power Range Positive Rate trip provides protection against rapid flux increases which are characteristic of a rupture of a control rod drive housing.

Specifically, this trip complements the Power Range Neutron Flux High and Low i trips to ensupe that the criteria are met for rod ejection from mid-power. l The Power Range Negative Rate t bp provides protection for control od drop accidents. At high power a single or multiple rod drop accident could cause

)

local flux peaking which could cause an unconservative local DN8R to exist.

1 The Power Range Negative Rate trip will prevent this from occurring by tripping the reactor. No credit is taken for operation of the Power Range Negative Rate i trip for those control rod drop accidents for which DN8Rs wi-11 be greater than he DNBR safety analysis limit.

Co mNCHE PEAK - UNITS 1 AND 2 B 2-4 Unit 1 - Amendment No. 14

Attachment 3 to TXX-94211 g Page 3 of 4 TABLE 3.3-1 3

g REACTOR TRIP SYSTEM INSTRtMENTATION m

g TOTAL NO.

MININUN x CHANNELS CHANNELS FUNCTIONAL UNIT APPLICABLE OF CHANNELS TO TRIP OPERABLE N00ES ACTION .

h 1. Manual Reactor Trip 2 1 Q 2 1, 2 1 v.

2 1 2 3*, 4*, 5* 9

2. Power Range, Neutron Flux N

a. High Setpoint 4 2 3 1, 2 2

b. Low Setpoint 4 2 3 1*, 2 2

3. Power Range, Neutron Flux, 4 2 High Positive Rate 3 1, 2 2 Not Use4- c R 4. P:xtr R:rge, " steen-Fivu,

• 4 2

"!gh "~;:tive R:te o 3 1, 2 2+

N

5. Intermediate Range, Neutron Flux 2 1 2 1*, 2 3

6. Source Range, Neutron Flux oo

a. Reactor Trip and Indication my 1) Startup 2

, , 2) Shutdown 1 2 2, 4 2 1 2 3,4,5 5 koo k 7. Overtemperature N-16 4 2 3 1, 2 12 kk 8. Overpower N-16 4 2

%A 3 1, 2 12 22 9. Pressurizer Pressure--Low 4 Id

?? 2 3 6 m, 10. Pressurizer Pressure--High 4 b .* 2 3 1, 2 6 G.)

o.

O

• I~

Attachment 3 to TXX-94211 8 TABLE 4.3-1 -

REACTOR TRIP SYSTEN INSTRUNENTATION SURVEILLANCE REQUIRENENTS

[

n 5 TRIP

,2 ANALOG ACTUATING N00ES FOR 9

CHANNEL DEVICE WHICH~

CHANNEL CHANNEL OPERATIONAL OPERATIONAL ACTUATION SURVEILLANCE FUNCTIONAL UNIT CHECK CALIBRATION TEST TEST LOGIC TEST IS REQUIRED x

1. Nanual Reactor Trip M.A. N.A. N.A. R(14) N.A. 1, 2, 3*, 4*,5*

]

4

[ 2. Power Range, Neutron Flux 2

[ a. High Setpoint S 0(2, 4), Q N.A. N.A. 1, 2 N(3, 4),

Q(4, 6),

R(4,5)

b. Lew Setpoint S R(4) S/U(1) N.A. N.A. 1*, 2

3. Power Range, Neutron Flux, N.A. R(4) Q N.A. N.A. 1, 2 w High Positive Rate I

No uwL 2 4. " ear R;r.g;t, Netetreet-Fitex, EA. R(4) Q LA. EA. 1,-2-R_ -

w ttigh "eget4ve-Rate p l

e3

5. Intennediate Range, S R(4, 5) S/U(1) N.A. N.A. 1*, 2 Neutron Flux 6

E, E, 6. Source Range, Neutron Flux S R(4,13) S/U(1),Q(9) N.A. N.A. 2 , 3, 4, 5 l

- 7. Overtemperature N-16 S D(2,4), Q N.A. N.A. 1, 2

.. N(3, 4),

pp Q(4, 6),

yg R(4,5) aa 52 8. Overpower N-16 S D(2, 4), Q N.A. M.A. 1, 2 AA R(4,5)

&. 5 9. Pressurizer Pressure--Low S R Q(8) N.A. N.A. Id

! .E

'm_

". 10. Pressurizer Pressure--High S R Q N.A. N.A. 1, 2 b . 1

- -- - -