- _ _ _ _ _ _ _

e .

E Idaho. Inc.

.__^"

INTERIM REPORT

Accession No.

Report No. EGG-EA-5106

C:ntract Program or Project Title: Electrical, Instrumentation and Control Systems Support

Subject of this Document: Electrical, Instrumentation & Control Aspects of ProposedTechnical Specifications Change Regarding Blocking of SafetyInjection Signals when Pressure is Below 2000 psig.H. B. Robinson, Unit 2

Type of Document:Technical Evaluation Report

S. E. MaysAuthor (s):

February 1980otte of Document:

.

R:sponsible NRC Individual and NRC Office or Division: Paul Shemanski. Division ofOperating Reactors

This document was prepared primarily for preliminary or internal use. It has not receivedfull review and approval. Since there may be substantive changes, this document shouldnot be considered final.

EG&G Idaho. Inc.k +jidaho Falls. Idaho 83401 .C

, H.iP.' Pearson, Supervisor[" Information Processing

Prepared for theU.S. Nuclear Regulatory Commissionand the U.S. Department of Energy

Idaho Operations OfficeUnder contract No. EY-76-C-07-1570

NRC FIN No.

A6256INTERIM REPORT

bJC'$!- i', h n g j T g d j d.,

ASSi.M:.o U Sqi;8004090%%

.. _ _ _ _ _ _ - - - - . _ _ _ _ _ _ _ _ _

-.

EGG-EA-5106

February 1980

ELECTRICAL. INSTRUMENTATION AND CONTR0!. ASPECTS OF|

PROPOSED TECilNICAL SPECIFICATIONS tilANCE RECARDING |5

:

ilLOCKING OF SAFETY INJECTION SIGNALS WilEN PRESSURE !,

|'IS BELOW 2000 PSIC.11. B. ROBINSON, UNIT 2

!1

S. E. Mays|

,

1

!i

!

U.S. Department of Energy !

Idaho Operations Offico e Idsho National Engineering Laboratory,

,. w .m s. , ,,,. u). G;,gy a., .. . m. ,' ' " a. pW,hg sw, . Mry'

kf~{ \! ,

$|tia[/ | g* N .r oa m q y,,,,, ,,,,N*Ci

~

Ne 055 ( ,, ,,

5$Y. $$ 5'C $? u.m . _" * ?'"*' Ww---acafW****

--,MM.

u ; u' ;

gg. ( Q ,~ K W h w ;' % T ~ j Lg * D'**~ SIT,M'"JC 4.y.;44_n _.3.gn,x-e--~wu -4._,$

~W\~ x-e~y

.]_..a ,,. A b_ . NAk hM "... __y -g,.'*

, .,

# ' "-*. l~-

4'. N _

'

d W N73,,: ~-

? k[r [dk h -.. m . ..

.

This is an Informal report intended for use as a preliminary or working document

!

O$' )It'.f } *j[j(f f6Ch[}p .

/kbM8[d[!L.OfiO[J[)f'fPrepared for the'U.S. Nuclear Regulatory Commission

Under DOE Contract No. DE-AC07-761D01570 0 g g g IdahoFIN No. A6256 $Q!

!L

Ap E G c G ,.......Fopu tcao m(Rev 11 F9)

INTERIM REPORT

Accession No.

Report No. EGG-EA-5106,

C ntract Program or Project Title:

Electrical, Instrumentation and Control Systems Support

Subject of this Document:Electrical, Instrumentation and Control Aspects of Proposed Technical SpecificationsChange Regarding Blocking of Safety Injection Signals when Pressure is Below 2000 psig,11. B. Robinson, Unit 2

Type of Document:Technical Evaluation Report

Author (s):

S. E. Kays

.

D t) of Document:February 1980

,

R:sponsible NRC Individual and NRC Office or Division:

Paul Shemanski, Division of Operating Reactors

This document was prepared primarily for preliminary or internal use. lt has not receivedfull review and approval. Since there may be substantive changes, this document shouldnot be considered final.

EG&G Idaho, Inc.Idaho Falls, Idaho 83415

>

Prepared for theU.S. Nuclear Regulatory Commission*

Washington, D.C.Under DOE Contract No. DE-AC07 76|D01570

NRC FIN No. A6256

INTERIM REPORT

fkO h C i,t piri gt h jiggiftd y g .-|r

1030F

.

,

TECHNICAL EVALUATION REPORT

ELECTRICAL, INSTRUME!(IATION, AND CONTROL ASPECTS OF -

PROPOSED TECHNICAL SPECIFICATIONS CHANGE REGARDING BLOCKINGOF SAFETY INJECTION SIGNALS MIEN PRESSURE IS BELOW 2000 PSIC

H. B. ROBINSON, UNIT 2,

Docket No. 50-261'

February 19809

S. E. Mays-

f

b

=

2/14/80'

.. i

CONTENTS

1.0 IITTRODUCTION . 1. . . . . . . . . . . . . . . . . . . . . . . . .

2.0 DISCUSSION . 1. . . . . . . . . . . . . . . . . . . . . . . . . ..

3.0 EVALUATION . 3. . . . . . . . . . . . . . . . . . . . . . . . . ..

4.0 REFERENCES . 3. . . . . . . . . . . . . . . . . . . . . . . . . .

.

0

.

9 9

11

1 ;'

TECHNICAL EVALUATION REPORT

ELECTRICAL, INSTRUMENTATION, AND CONTROL ASPECTS OFPROPOSED TECHNICAL SPECIFICATIONS CHANGE REGARDING BLOCKING

OF SAFETY INJECTION SIGNALS WHEN PRESSURE IS BELOW 2000 PSIG

'

H. B. ROBINSON, UNIT 2

,

1.0 INTRODUCTION

The objective of this review is to evaluate if plant safety isdegraded by allowing the proposed changes to the H. B. Robinson, Unit 2Technical Specifications to allow blocking the "High Differential Pres-sure Between any Steam Line and the Steam Header" Safety InjectionSystem (SIS) initiation when primary plant pressure is less than2000 psig (as in cooldown operations). This change was proposed byCarolina Power and Light Company in their letter Utley to Schwencerdated March 6, 1979.

.

.

2.0 DISCUSSION. _

The present H. B. Robinson, Unit 2 Technical Specifications allowblocking the " Pressurizer Low Pressure and Low Level" SIS initiation

when primary pressure is less than 2000 psig (as in cooldown oper-ations). However, the same switch which blocks this signal also blocksthe "High Differential Pressure Between any Steam Line and the Steam

Header" SIS initiation. Table 3.5.3 of the Technical Specificationspresently does not allow this signal to be blocked under any condi-tions. Therefore, Carolina Power and Light Company has requested thatTabic 3.5.3 of the Technical Specifications be changed to allow block-ing the "High Differential Pressure Between any Steam Line and theSteam Header" when primary plant pressure is less than 2000 psig.

>

Section 14.2.5 of the H. B. Robinson, Unit 2 Final Facility.

Description and Safety Analysis Report (FEAR) discusses the factors

protec ting the core in the event of a steam line rupture. The SIS

initiation and rapid closure of the main steam isolation valves isrequired to ensure that the possible return to criticality will not

I

F-

result in sufficient heat flux to cause core damage and to ensure thatadequate shutdown margin is maintained.

SIS initiation and rapid closure of the main steam isolation valves.

during a steam line rupture can be initiated by any of the followings ignals . .

(1) Pressurizer Low Level and Low Pressure

(2) High Differential Pressure Between any Steam Lineand the Steam Header

(3) - High Containment Pressure

(4) High Steam Flow in 2/3 Steam Lines Coincident withLow T or Low Steam Pressure.avg .

Technical Specifications, Table 3.5.3 allows blocking signal (1) above .

when primary pressure is less than 2000 psig. The proposed changewould also allow signal (2) above to be blocked when pressure is lessthan 2000 psig.- This would leave only signals (3) and (4) above avail-able for SIS initiation and rapid closure of the main steam isolationvalves in the event of a steam line rupture. Table 3.5.3 of the ~ Tech-nical Specifications requires a minimum of two containment pressurechannels to be operable with one degree of redundancy. It also requires

operability of at least one steam line flow channel per loop, two T ,ychannels with one degree of redundancy, and two steam pressure channelswith ~ one degree of redundancy. Therefore, SIS initiation and core

protection is provided by two separate redundant systems if both sig-nals (1) and (2) above are blocked when the primary pressure is below

42000 psig.

.

Furthermore, as noted in NRC Memo f rom J. H. - Sniezek to 'D. Eisenhut,dated April 5,1978, the steam header pressure transmitter range. is sonarrow that safety injection will occur during nonnal cooldown opera-tions unicas the "High. Differential Pressure Between any Steam Line and

2

,

, , - -_ _s____- ___

__ - _ - - _ __ __ _ _ _ . -. . _ _ - - _ _ . ._

,

the Steam Header" signal is blocked. Such a safety injection couldresult in an uncontrolled cooldown and possible plant overpressurizationwhich is undesirable.

''

3.0 EVALUATION

+.

The NRC staff position stated in generic letter of November 28,1978 required that all licensees " review the design of all safety actu-ation signal circuits which incorporate a manual override feature to

j ensure that overriding of one safety actuation signal does not also; cause the bypass (block) of any other safety actuation signal, thatj sufficient physical features are provided to facilitate adequate admin-1

[ istrative controls, and that the use of each such manual override isannunciated at the system level for every system impacted." It isrecommended that the switch which blocks both the " Pressurizer LowLevel and Low Pressure" signal and the "High Differential Pressure

*

Between any Steam Line and the Steam Header" signal be modified tocanply with this staff position.,

!

It is recommended that the proposed change to Table 3.5.3 of the P

H. B. Robinson, Unit 2 Technical Specifications to allow blocking the"High Dif ferential Pressure Between any Steam Line and the Steam Header"

signal when primary pressure is less than 2000 psig be allowed. Ade-quate protection from a steam line rupture is provided without thissignal by independent and redundant systems. Additionally, this will

i prevent inadvertent SIS initiation during cooldown due to the limitedrange of the Steam Header Pressure transmitter.

4.0 REFE RENCES;

1. CPLC letter (Utley) to NRC (Schwencer) dated March 6,1979..

2. H. B. Robinson, Unit 2 Technical Specifications, Table 3.5.3.

3. H. B. Robinson, Unit 2 Final Facility Description and Safety Anal-,

ysis Report.

3,

- - _ . ... _ _- - .. __ _ -.

- ._ , _ _ ._ -. -- . _ _ . _ . - _ . . - - _ _ . _ _ . _ __ .. ._._

i

Ii

1

i

1

j 4. NRC Mano J. H. Snlezek to D. Eisenhut, dated April 5,1978. ;

i

5. NRC generic letter dated November 28, 1978, Containment Purging

| During Normal Plant Operation.,

,

i.*

,

d

a e

'fI >

.i >

i i

A

;

i4

e

d

14

.

>

.

t

*!<

. ,

o

:

It

i

t

.j.

|.

,

,

i'

it

\ 4i.

k

! !*

i i

,

I't

1i

L

4 .

iI

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