ML20154J171

Discusses Review of Licensee Describing Sys to Mitigate Effects of High Energy Line Breaks in Steam Generator Blowdown Sys & Auxiliary Steam Sys.Possibility of Including Branch in Review Requested

ML20154J171
Person / Time
Site:	Byron, Braidwood, 05000000
Issue date:	03/03/1986
From:	Olshan L Office of Nuclear Reactor Regulation
To:	Rosa F Office of Nuclear Reactor Regulation
References
TAC-59441, NUDOCS 8603100496
Download: ML20154J171 (2)

Text

_ _ - _ . _ _ - _ _ _

co ac4 ,

)C/fd hh0 E 0 3126 MEMORANDUM FOR: F. Rosa, Chief. Electrical, Instrumentation and Control Systems Branch [9gf N FROM: L. 01shan, Project Manager PWR Project Directorate #5 Division of PWR licensing-A

SUBJECT:

REVIEW ASSISTANCE FOR BYRON /BRAIDWOOD SYSTEM TO AUTOMATICAl.lY IS01. ATE HIGH ENERGY t.INE BREAKS l By letter dated August 2,1985, (copy attached), Commonwealth Edison described a system it was installing to mitigate the effects of high energy line breaks in the Steam Generator Blowdown System and Auxiliary Steam System. The proposed system which has since been installed on Byron 1, utilizes temperature sensors and isolation values to isolate the breaks.

A TAC was written (TAC #59441) and routed to Auxiliary Systems Branch.

Their review, being done by D. Katze, is nearly complete. F. Burrows of your branch has recently informed me that perhaps your branch should also be involved in the review. If you believe that your branch should also partake in this review, please let me know so that we can discuss schedule, review status, assigned reviewer, etc.

I.. Olshan, Project Manager PWR Project Directorate #5 Division of PWR I.icensing-A

Enclosure:

As stated Distribution:

NRC PDR local PDR PD#5 Reading File L. 01shan M. Rushbrook 0FC : 5  :  :  :  :  :  :

NAME 1shan  :  :  :  :  :  :

DATF : 3/3 /86  :  :  :  :  :  :

OFFICIAL RECORD COPY hhbob P

4

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1. vq[o 8 c UNITED STATES b{ ,I NUCLEAR REGULATORY COMMISSION WASHING TON, O. C. 20555 s .

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. m oa w HEMORANDUM FOR:

F. Rosa, Chief Electrical, Instrumentation and Control Systems Branch FROM: t.. Olshan, Project Manager PWR Project Directorate #5 Division of PWR licensing-A

~

SUBJECT:

REVIEW ASSISTANCE FOR BYRON /8RAIDWOOD SYSTEM T AUTOMATICAl.lY ISOLATE HIGH ENERGY LINE BREAKS By letter dated August 2,1985, (copy attached), Commonwealth Edison described a system it was installing to mitigate the effects of high energy Steam line System. breaks in thesystem The proposed Steam Generator Blowdown System and Auxiliary Byron I, utilizes temperature senso,which has since been installed on the breaks. rs and isolation values to isolate A TAC was written (TAC #59441) and routed to Auxiliary Systems Branch.

Their review, being done by D. Katze, is nearly complete.

your branch has recently informed me that perhaps your branch shouldF. Burrows of also be involved in the review.

also partake in this review, please let me know so that we can discuss schedule, review status, assigned reviewer, etc.

A$

l. 01shan, Project Manager PWR Project Directorate #5 Division of PWR licensing-A

Enclosure:

As stated

Lo Commonwealth Edison One First habonal Plata Crucago ilhno3

• Address Reply to Post Office Box 767 Chicago. Illinois 60690 August 2, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 i

j

Subject:

Byron Station Units 1 and 2

.t Braidwood Station Units 1 and 2 2

Environmental Effects of High Energy Line Breaks

{ NRC Docket Nos. 50-454, 50-455 r

r 50-456 and 50-457 References (a): May 17, 1985 letter from K. A. Ainger to H. R. Denton (b): May 20, 1985 letter from B. J. Youngolood to D. L. Farrar

'I

Dear Mr. Denton:

Refersace (a) informed you of revised predicted environmental patameters resulting from high energy line breaks in the Steam Generator Blowdown (SD) and Auxiliary Steam (AS) systems. High energy line breaks in these systems were found to have a greater potential effect on environmental conditions than originally predicted. In order to justify continued operation of Byron Unit I until permanent mooifications could be installea, we have posted personnel at designated locations in the Auxiliary Building so that the breaks coulo be promptly detected and terminated manually before environmental conditions exceeded predicted values.

Included in reference (a) was a conceptual description of our plans for the permanent modifications to the of detect and isolate these breaks along with our schedule for installation modifications.

Reference (b) provided your concurrence with our temporary measures to deal with the effects of these lines breaks and also requested that we submit the details of the permanent modifications for NRC review. Enclosed is a detailed technical description of the permanent modifications that will be installed by August 31, 1985 on Byron Unit 1.

The mooifications consist of temperature sensors mounted in potentially affected areas coupleo with automatic isolation of the systems, control room alarms, and appropriate procedures.

H. R. Denton August 2, 1985 Similar modifications, depending on specific break loc'ations, will be installed respective fuel on Byron Unit 2 and Braidwood Units 1 and 2 prior to their load dates.

.. Please address any questions regarding this matter to this office.

are provided Oneforsigned original and fifteen copies of this letter and enclosure NRC review.

Very truly yours, K. A. Ainger Nuclear Licensing Administrator Im Enclosure cc: Byron Resident Inspecto 0457K

ELB MONITCRING/ ISOLATION DESIGN FOR SD AND AS SYSTEMS In order to assure that a high energy line break (HELB) in the Steam Generator 810wdown (50) or the Auxiliary Steam (AS) Systems does not result in significant increases in Auxiliary Building temperatures, modifications are being made to isolate those systems in the event of a break. Due to the internal flow resistance of the systems and the potential for a variety of break detection.

sizes, system flow monitoring was found to not be an optimal method of

?

break The modifications, therefore, consist of temperature f sensors mounted in potentially affected areas coupled with automatic L isolation of the systems, control room alarms and appropriate procedures.

t i SD SYSTEM MODIFICATIONS Tne SD System consists of blowdown lines from each steam generator which penetrate the containment boundary ano travel through the Main Steam Tunnel toBuilding.

Auxiliary a point (station location Q-10) where the lines penetrate into the In the Auxiliary Builcing ble piping is then routed into the blowdown condenser room. Breaks are postulated at the point where the piping enters the as shown on Figure IC.

Auxiliary Building and in the blowdown condenser room on FigureTemperature IC, Sensors are being installed at the locations indicated At each of these sensor locations, redundant IE instruments will be installed, receiving power from electrical divisions 11 and 12, respectively.

knen the temperature in either area reaches 1500F, an alarm will be sounded in the control room and the four SD containment isolation valves will be automatically closeo as shown on Figure 18. These valves are snown on Figure 1A (S0002, B, D, F ano H). As shown on Figure IA, the SD System has only one containment isolation valve on each line due to the fact that it is a closed system insice the containment and requires only one automatic isolation valve to meet GDC requirements for containment isolation.

As a redundant feature to assure that the system is isolated in the event of a malfunction of one of the 50002 valves, procedures will be developeo to require local manual isolation of the system by closing the 50001 valves when the alarm in the control room is activated. This can be accomplished because the 50001 valves are located in the safety valve rooms which are remotely located from Auxiliary building break locations.

AS SYSTEM MODIFICATIONS The AS System provides low pressure (50 psig) steam to various Auxiliary building loacs inclucing the boric acid and radwaste systems.

Auxiliary steam is furnished either by the AS boiler or by extraction steam.

In either case the AS routed to the Auxiliary Building flows through pressure

c, regulating valves AS013 and AS167 in the Turbine Building and is then routed in the Auxiliary Building in the AS Tunnel where it is distributed to various losos (see Figure 2A). At postulated break locations in the Auxiliary Building where the break is large enough to affect a large general area and the break effects cannot be shown to be restricted to non-safety areas, temperature sensors are being installed to alarm if the temperature reaches 1500F and to initiate automatic isolation of the AS System from the Auxiliary Builcing areas. Figures 2C through 2F show the break locations and sensor locations.

- Tne temperature sensor design provides IE redundant instrumentation at the necessary locations. When the temperature reaches 1500F, a signal will be initiateo to close tne A5013 and AS167 valves (Figure 28) and an alarm will annunciate in the control room. These valves fall closed and are located in the Turbine Building in the Category II portion of the AS System. The electrical system (caoles, conduit, and solenoids) for the AS013/AS167 isolation is made up of IE components which have been reclassi-fled as non-safety because they cross into the Turbine Building, while in the Auxiliary Building the system is seismically supported. To assure that steam flow is isolated in the event of failure of the A5013 or AS167 valves, procedures will be developed requiring local manual closure of valve A5012 after receipt of the control room alarm. This will provide redundancy in the isolation of tne AS System and can be accomplished because the A5012 valve is locateo Builoing in the Turbine Building remotely located from the Auxiliary break locations.

d 0435K

. , w

{lGURE 1A STEAM GENERATOR BLOWDOWN CONFIGURATION

'- ~

( UNIT 1 A' . .

-s  :

]

) ~

. .~.

SDOO1 B,D, F orH -

1 SDOO28,D, F orH -

,s

.4.- -

4 _-

~

+ ._

a I i 1 '

BLOWDOWN

[*'. , \ . .;l. . 3;. . CONDENSER

.. c n .1. .... -

STEAM - ^ < t. ,

{ GENERATOR

- ISOLATION VALVE ROOM _ STEAM TUNNEL AUXlLIARY BUILDING

--4 4_ --1---

CONTAINMENT

• WALL i .

S e

• l l

g - . . . .u -

FIGURE 18 S.G. BLDN ISOL VALVES '

TEMPERATURE CONTROL

( BLOCK DI AGRAM ) -

AREA 1 AREA 2

_ S D PIPE PENETRATION CORNER )

CONDENSER ROOM  ;

(E21)E11 (E21)E11 (E22)E12(E22)E12 '

TEMP. (E21)E11 (E21)E11 (E22)E12 (E22)E12 TEMR TEMP. TEMP.

I SWITCH TEMP. TEMP. TE!*1P. TEMP.

SWITCH SWITCH SWITCH SWITCH SWITCH SWITCH SWITCH U _U < <-

U U V -

U U U(E21)E11 I(E22)E12 RESET RESET HAND SWITCH HAND SWITCH , .

SOL = DESCRIPTION OF OPERATION 0

(2)lSDOO2B WHEN TEMPERATURE REACHES 150' F IN ANY OF TWO AREAS,THE CORRESPONDING SOL C = TEMPERATURE SWITC+iES WILL ACTUATE TO C LOSE ALL FOUR ISOLATION VALVES.

(2)lSDOO2D REDUNDANT SWITCHES ARE PROVIDED TO SOL . AVOID ANY MALFUNCTION.

C ~ .

VALVES REMAIN CLOSED UNTIL THEY ARE (2)lSDOO2 F MANUALY RES-ET. -

SOL _ '

C

~ -

(2)lSDOO2H

..-.- .v STEAM GENERATOR BLOWDOWN SYSTEM HELB MONITORING h _

s (UNIT 1) 73-6

, h (1 SDO1ES 3 (1 SDO1E A 3)

(1SDO1ED 3 -

1SDO1EC 3) OSDO1F 6)

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1 / 2

-HF- #

[3 .

I . ;. .

,3", ?- 1 I i 1

_I o

0 k e , .yQ'd r i. I I I I

• [,ff./.k 1Ill _

III I -,

- - 1 - -

A3OO s L H

H L

A301 A304 ' ' ~

• N 3

H ' :p A302 A305 - -

i A303 'I (ISDO1LA 14 h N

• E TS E TS TS E f6

_k TS E _t 1 2 -

v

[j, 3 '

, TS g TSQhd(1SDO1LB 14)

~

//

l 2

E TS LEGEND. TYPICAL FOR FIGURES E TS -

2C,2D,2E L 2F R 13 LOWDOWN CONDENSER TUNNEL _ _ AUX.

( $ . TEMPERATURE SENSOR 1SDO1A EL,364'- O'

' HIGH ENERGY LINE BREAK NO.

-AREA ' BLDG. .

i( )LINE IDENTIFICATION g , . -me

, FIGURE 2 A AUXILIARY STEAM CONFIGURATION .

(UNIT 1) l .

l OASO13 ~Y~

OAS 012 l Ch -

s

--C3

~

l AUXILIARY  : )

STEAM BOILER O AS167 -Y-r TURBINE AUXILIARY

. EXTRACTION ES BUILDING BUILDING i STEAM i e 1

i l

O ,

4 ,

FIGURE 2B AUX.STE%M ISOLATION VALVE '

TEMPERATURE CONTROL (BLOCK DIAGRAM)

RECYCLE EVAP. RECYCLE EVAP. RADW. EVAP.OA RADW.EVAP.OB RADW EVAP OC AUX STM TUNNEL OA OB E 11 E 12 E 11 E 12 E 11 E 12 E 11 E 12 E 11 E 12 E11 E 12 TEMR TEMR TEMR TEMP. TEMP. TEMP. TEMP. TEMP. TEMP. TEMP. TEMP. TEMP.

SWITCH SWITCH SWITCH SWITCH SWITCH SWITCH SWITCH SWITCH SWITCH SWITCH SWITCH SWITCH U e U e U e m U < U e U

) ,

) m n

) ) ) U U l' DESC RIPTION 'OFOPERATIO N RESET RESET WHEN TEMPERATURE REACHES 150* F HAND SWITCH HAND SWITCH

, IN ANY OF SIX AREAS, THE CORRESPO,N DING TEMPERATURE SWITCHES WILL ACTUATE TO CLOSE AUX.STM.lSOL. VALVES (OASO13, OAS167). REDUNDANCY IS PROVIDED TO SOL AVOID ANY MALFUNCTION.

! A e VALVE REMAINS CLOSED UNTIL IT IS l MANUALY RESET.

! OASO13-AFSV AND ..

I O AS 167- AFSV ' -

l ~

l SOL '-

j B * .

OASO13- AFSV AND OAS167- AFSV

. i v u n c. e v AUX. STEAM SYSTEM HELB MONITORING (UNITS 1 &2) 22 23 (AS TDNNEL AT COL M-23) '

i, _ 6*- O ' _ _

21'- 3" ~

, p i s ?l,Vs'.1: yYe .* 5 d *

! .,':tji*i-:; ,,

" i.,;::y- .*3r -

a (O AS 33C - 6)  ; '}

, (O AS .

3OC -i 4)  : -

l i

(OAS O3F-16) = -

~

TS .

i i

i l .$,'lh::

• ..:. TS

.:f*se-s

, .s .:,: ..

~.; . . . *:

. :. s e ;.

i BOTTOM TUNNEL o

i EL. 394*-O' AO2O e

1

- q' - . -

l o a n+ O n

,g

\ l'k,-'{'): [ 3I es:a:.. . ' .

_(' i 'l :s.

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e h . .'- l AOO7 l $. .'5.;

Q$' ,

, qi -

j l

i bI i

l I AO13 I

- ,~

l ~

. I d..

LEGEND: -. ,'

i l SAME AS FIGURE '1C 1

k i

s. . . .

AUXILIARY STEAM SYSTEM HELB MONITORING (UNITS I&2 ma , r.

y -

(RECYCQ WASTE EVAPORATOR ROOMS)  ;

. f 00S a w.

I ,

p- OASO3KB-6} (OASF6AA1 (OASO3KA 6) g .  ;. a f

@ASF6AB-lh (OAS03LA 4 DOD) 1 LEGEND r--U><1 "

(OASO3LB-4 SAME AS ( =

r OAS35AB-2)E D FIGURE IC ~'

@AS3 c y

@AS35AA-2) _

, tie =1 E55=i O (OAS35AD-3/4) "

- -84 i

. EEEH EEEHI O' i U- --

>Q i

" 5 SLBTLBE l -

EVAP. , N n _:-~ SLBTUBE

.3 ABO 2DA EVAP.

u EVAR '

CABO2DB COND.

u EVAP.

9 ' .

COND.

V J

N f  % ._

'o (OAS36 BA-l) ,

\

(

kv OAS i

h e

v

~

(OASF5AAlt- U 3 l OASF7AB N'2 MOOD '

y - -,

g - - -

(OAS36AB-l)

-4>< IAOO3

- -V - OASO4BB 27

, J i

N --{ 36 M

TS B TS E \\ O X

" _4 -

Q', I lill i

\K '

m

~

OTS ,  :>0 '"3 h; ~4 (CAS36C-II IAOO2] (QASO4AA-2) Ih '

' t*'t gll }l kOASO4C-3) -

04M-2) 17 * (~ gp, 7 (OA596A _lO) ' - _

17'6~

EL346'-O' 7 . _ _. ..... .. .

Q3)

AUXILIARY STEAM SYSTEM HELB MONITORING (UNITS 1&2)

AUXILIARY STgAM (RADWASTE EVAP. ROOMS) 7 3'- 6 * '

{

8 I

$>[' O (OWXY9AB 20) j3 T _ E TS E TS E TS

a. ka Y -

5 TS E TS ' ~

l (OAS32AA 10 (OAS3 2AB 1 OAS29A 10)

N 2AO10 2AOO8 -

4- m '

< VAPOR BODY "

U g U 4 '-

2AOO9 g -

s g - TANK OWXO7DC m 4 e-- __ - -j N I e-

_ z -

m g- ..3 -4 m

X T 2A614 -

I g y i 3 VAPOR < VAPOR x"

,Os BODY TANK v 3 3 OWXO7DA 3

BODY TA)4K "

O -

2AO12 O X OWXO7D8,/ ' X s l i 3 '

2A623 N / ' ,

- V< i s N i d /

A606- N  % G,,

3 /

2A604 ( 2A624 /

A600 --

A 605 - -

2A615 -

p. ---/y 2A618 -

, _ (_

,4 2A609 2A619 I l.

A601 "h

~ '

F- -~

2A610 - '" '"

2A620 -

s

~

I

- - ~ -2A622 i

A 602 I 1 2A 611 --

M 2 A613 'l _

^

!p yp 2A603 MP 2A612 I OWX31PA HEATING PUMP OWX31PB t[ HEATING

( ELEMENT ELEMENT OWX31PC i HEATING OWXO6CA ELEMENT OWXO6DB

.(OWX 113 AC 18 .

\.

(OWX113 AA 18 (OWX113 AB 18) i .

OT g PERATURE SENSOR LEGEND .

?ROTECTING THESE AREAS e a uc 4 e r .c sc EL 414'-O' ALSO PROTECT AREAS SHOWN ON FIG. 2F (401'-O T' .

.. .m .r (23)

AUXILIARY STEAM SYSTEM HELB MONITORING (UNITS 1 &2)

AUXILIARY STEy (RADWASTE EVAP. ROOMS) 73'- 6' h

. =

l4 g' CAS33AA- 4 ) OAS32AA-10)(OWX 105BB-2 OAS32 AB-103 r '

(OAS 3O B - 4")  ;.,

OASO3F-16) -(OAS 0 3G - 14 OA S29 A - 10) 7 ,_

g OWXI06eA-2}- y @ - -=

I fW p -- -

tw* O OWX105BC- 2$

<XI 05AA-2)- h f jp;;>c1 x 7'p31

-l 1-f '

1. 1. ' d' ,

[ -- W N ,{ l  : M 1AO251 E

J1A603 b IO5AE-2) , (OWXIO5AC-2~

OWXIO5AD-2)

WXIO5AB-2) NIOSAF-2:

l  %

--OAS95AA-2) h AS95AB-2) - g DAS95AC-2 I

f14608 Q Mg4) C WXY9ABPQ) f- (OWXY94G2d

/ ,." L-. 1A0211

• M462d d

w

/ . -

w - _

i J RAD. EVAe "

AD. EVAe I \ 1I A617 RAD.EVAR CONDEN$ER CONDENSER CONDENSER ONXC8 DNXO8C B , DWX08DC

= -

=

WXY9AA-20) (OAS33BB-4 ) .

NOAS 3OC MF - ' '

CAS33BA-4) yH - \

- -- = w r

\ . --

IFGEND-OAS33AB-4) NOTE: b,$h TEMPERATURE SENSORS s,

' .SAME AS FIG.1C

~'- '

EL., 401'-O PROTECTING THESE AREAS ARE THE SAME AS THOSE l'

i NDICATED ON FIGURF 2E (EL 414*-O')

__ __ -