ML19263D388

Review of Intergranular Stress Corrosion Cracking Completed. Changed Piping Matl or Design to Have No Nonconforming or svc-sensitive Piping.Replacing Sections of Piping W/316L Stainless Steel W/Max Carbon Content of .02%

ML19263D388
Person / Time
Site:	Limerick
Issue date:	03/26/1979
From:	Boyer V PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Baer R Office of Nuclear Reactor Regulation
References
NUDOCS 7903290130
Download: ML19263D388 (5)

Text

-

. .

,

,

.-

PHILADELPHIA ELECTRIC COMPANY a

2301 M ARKET STREET PHILADELPHI A. PA.19101 (215)841-4500 V.S.DOYER n v a m.,wa March c6,19 79 Mr. R. L. Baer, Chief Light Water Reactors Branch #2 Division of Project Management U. S. Nuclear Regulatory Commission Washington, D. C. 20555

SUBJECT:

Limerick Generating Station, Units 1 and 2 Dockets No. 50-352 and 50-353

REFERENCE:

Letter dated September 8, 1978 E. J. Bradley to Mr. Karl Kniel

Dear Mr. Baer:

In Mr. Bradley' u letter to Mr. Kniel dated September 8, 1978, he advised that we were reviewing recommendations f rom both General Electric and our architect / engineer and studying various options to mitigate intergranular stress corrosion cracking.

We have concluded our review and effer the following response to the NRC Staff Position contained in NUREG-0313.

We iio.c tisaugeu piping material or design to the extent that we will have no piping which is non-conforming and service sensitive and we will have very little piping which is non-conforming and non-service sensitive.

These are the changes which are being implemented:

The following sections of piping are being replaced with 316L stainless steel with a maximum carbon content of 0.02%. (System sketches are included for reference).

Reactor Water Clean Up: RHR suction through the containment flued head.

Head Spray: The flange mating to the RPV flange out to valve F022.

7903200 /30 T\

M

• *

.

.

Page 2 Shutdown Cooling Suction: Recirculation piping out to valve F009. Valve F077 remains unchanged.

Shutdown Cooling Return: Recirculation piping out to valves F050A and B.

LPCI: From RPV safe ends out to valve 41A, B, C, and D. Valves F065A, B, C, and D remain unchanged.

Core Spray: From RPV safe end extensions out to valves F006A and B. Valves F007A, B, C, and D remain unchanged.

Also the entire recirculation system piping is being changed to Type 316 stainless steel with a maximum carbon content of 0.02%.

Of the valves in the above systems, those made from Type 304 stainless steel castings with a high delta ferrite content or from carbon steel were not changed because of their resiocance to intergranular stress corrosion cracking. All of the 304 type stainless steel forged valves are being changed to 316L with the exception of F009.

All of the austenitic stainless steel safe ends will have carbon contents of less than 0.035%.

We consider the following piping to be non-conforming and non-service sensitive:

llead Spray: From valve F022 to the outer isolation valve.

Shutdown Cooling Suction: From and including valve F009 to the outer isolation valve.

Shutdown Cooling Return: From valves F050A and B to the outer isolation valve.

Core Spray: Between the isolation valves.

Inservice inspection and leakage monitoring guidelines of KUREG-0313 will be addressed in the FSAR which is in preparation.

Very truly yours,

/ Jc V. S. Boyer PAT /dh13/3

.

.

.

.

RHR SHUTDOWN COOLING SUCTION & RETURN l

.

I i

,

/  ; .

/ .i .

IFo:7 IfbCO Ir&>O ' ~ ^ ~ '

u-

._ ll ,tyr

'

IV pp y ff 94.-

_

-g-m/ . - . wI - . - - . -

68f3 '/ DCA DCA

, ( 3) (f)

- 1~ ..

,

(

' gj IF077 IF009 9 95

_.

% .._ Q __ _ _ 2 0 - .

Ty _.

,

' l

• t

, i

,

DCA DtA M (0 (2) O) ( 2)

PIPE CLASS CBB - CARBON STEEL SA-106 Gr. B DCA(1) - STAINLESS STEEL SA-358 TP 316L ( 5 0.020%C)

DCA(2) - STAINLESS STEEL SA-358 TP 304 f

, .

.

.

RHR-LPCI IFOI? IFOM trO LE i

-

~

>{ . - b] 12 ' . -( 1

--

- -- - - p3 gA . - .- _ H . --_ -

-

RPV

-

pf_ . [sj gg _ __.. . p.q M _

H . . --

lI

,

'

.I

~

CrFaE. 7 OcA DLA i DCA r2 '

M l (2) l (i)

OA CORE SPRAY

\ Foot 17o 0 6 . Irc77 l 1 ho cr3 gh __ _ __ y '! -p. ___g- . _p . _ _ . - _ _ [__ ,4 .__

-~

. / '

,

! /l PPV

-c - -.__.___.. 4._..

06E lipcA IDCA

( 2.) l Ot A lLYA (U (s)

W.

l

\

PIPE CLASS EBB - CARBON STEEL SA-106 Gr. B CBB - CARBON STEEL SA-106 Cr. B DCA(1) - STAINLESS STEEL SA-358 TP 316L ( IE 0.020%C)

DCA(2) - STAINLESS STEEL SA-358 TP 304 DLA - CARBON STEEL (IMPACT TESTED) SA 333 Cr. 6

.

.

'

,.

RWCU i

i lF027 Ipo0I ;i;;;

f - .-

. - J,.-j - - . . . l l,1 ---- ..( y-i

, h , ,

F

- - -

- p. . g _ . ,

'

D;g  ! pcA  ::t I D;4 c,3# ( #3 D c ts

( 2) (21 l

RNR Sucrior)

IIEAD SPRAY

'

(Foz3 IFo22 IPO!9 t

---

il D4

,

-Hl  !\l i

see Da L-Gi38 Il / s)

~

Oc6 Oc gy,;

PIPE CLASS ECB - STAINLESS STEEL SA-376 or SA-312 TP 304 DCB - STAINLESS STEEL SA-376 or SA-312 TP 304 GBB - CARBON STEEL SA-106 Gr. B DCA(1) - STAINLESS STEEL SA-358 TP 316L ( C 0.020%C)

DCA(2) - STAINLESS STEEL SA-358 TP304

.