ML20084V023

Responds to AEC Re Insp & Evaluation of Tori for Both Units.During Refueling Outage,Relief Valve Piping Supports Modified to Accommodate Blowdown Reaction Forces W/Greater Margin of Safety.Insp Scheduled for Jan 1973

ML20084V023
Person / Time
Site:	Dresden
Issue date:	03/24/1972
From:	COMMONWEALTH EDISON CO.
To:	Boyd R US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084V010	List: ML20084V023 ML20084V027
References
NUDOCS 8306290718
Download: ML20084V023 (1)

Text

- - - - - - -- -

, ,e o _ -,

&mw.i  :. % : iD.. % &...av.,.w ~.JG.. Mh.M

- .. . 45s cf.

c l; _..x. _%2. -. . . . m , . ;,, ' , f RW ts' , <. :s .s:

.s.,. yp y-- 1..~.,q

, - i

. 3-.., j -". g y h y % g :

. __ -nw + n#.f. .

tC. 3 2'.

y r .m . u ..

- 9+: s ~-@& . ~ m%%m%.:"'N. ,Qfq&7/tsw&e2 W f"$

1, ,:

a x.

4' . _

g.-

e=, -

-u Q 1t "b .

I"i . C'.-

%.* M =

?.f6 y

c

y. aal-ggy,

,. -w t h - .

c.,

jj Commonwealth Edison C_ompany OhE F i f, % T NATEONAL PLAIA 4 9a QMICAGO. BLLIMOIS 'j I'!

[ a

• e...

r. ...,o...<. ... ... . <,,,c..... ...........

4]

r.

b March 24, 1972 s f 1 Q t

, 10 ,

, Mr. Roger S. Boyd, Assistant Director p kdy , () -

[ '

t for Boiling Water Reactors Division of Feactor Licensing

'I

,k* . gl l~ U.S. Atomic Energy Commission Re.Mry Fue Cy. k  !

,/

Washington, D.C. 20545 '

Subject:

Inspection and Struqtural Capability of the Dresden Units 2 and 3 Tori I '

7

Dear Mr. Boyd:

W 3 This is in respense to your letter of March 13 concerning

, k.

the inspection and evaluation of the tori for Dresden Units 2 and 3.

.t At the present tino, Dresden Unit 2 is undergoing a y

a refueling outage. During this outage, the relief valve piping supports have been modified to accommodate the blowdown reaction

• O.

• forces with a greater margin of safety. This modification is

. complete. Prior to this modification, the supports had been

(- inspected and no indication of distress was found. In addition, i during the present outage, the baffles will be inspected. The 7 torus is presently being drained and this inspection of the baffles J should be completed within the next week.

An inspection of the piping supports and baffles in the Dresden Unit 3 torus has been scheduled for January 1973. This ,

schedule is based on the fact that no abnormal structural conditions ,

were observed on Unit 2 during its inspection. In addition, the  !

rehef valve piping was modified approximately one year ago and is not the same as the Monticello design.

1l e,,

- o -

d s

' & bUg 4 p

Y 15; c

' AAOO[94""p.)

~

~~

i 8306290718 720526 '

en

.w g g

~

PDR ADOCK 05000237 l

+1 ' G PDR 9 l .

a Y J * [:  :( b -

W '

hu, w, n<wx.f& Ww; 9mw.w

v

= ' , -

- 4 r L '? ~ ,. l~'..lj,%AW

- - * ~m

%~~1 g n;q g , ;- u.-.- -

w. m. a. s - av . -

q@Q{5 ~

. = On. .a.~ ~ -- n s w s, W T

, r-0D

' ^

1. a'fp'/6 f UNITEQ STATES f\' g

.;3 ATOMIC ENERGY COMMISSION wm nm. , o~ m . .. e

"'" " p' MAR 131972

!)ocket Nos. 50-237 nnd 33-249 Commonwealth Edison Company ATTN: Mr. Byron Lee, Jr.

Assistant to the President P.O. Box 767 Chicago, Illinois 60690 Gentlemen:

The Dresden 2 and 3 facilities still have baffics installed in the torus suppression pools. We have concluded, based on our evaluation of previous analyses. that these baffles are not required to assure that the suppression pools will perform their intended functions regard-ing condensation of steam discharged to the tori.

A recent inspection made by Northern States Power Company at their Monticello plant revealed damage to the torus baffles and other d-y struct zal components installed in the suppression pool. The Northern States Power Company, assisted by the General Electric Company, has -

removed all of the torus baf fles and has also taken corrective steps '

regarding other utructural damage, including the anchorages for the blowdown discharge pipes .

If you have not already done so, please plan an inspection of the tori of your facilities with special emphasis on the structural condition of anchorages, baf fles, and other structural appurtenances. Subsequently, provide us with your evaluation of the effects of all blowdown forces into the tori on the installed torus baffles, other torus structural components, and blowdewn vent pipe anchorages and a proposed course of action to avoid any safety problems in the event these effects exceed acceptable structural design criteria.

Please let us know within two weeks your schedule for the inspection and the submittal of the reques ted information.

Sincerely,

.' O 3 _ - - ?.S '

Roger S. Boyd, Ass'fstant Director for Boiling Water Reactors

[

N gg Division of Reactor Licensing tc

See neM page t

}

cor car nmioN M5

. - _ _ - - _ _ . - _ _ _ _ ~ _ - _ _ _ . _ _ _ - --

r_

Ceauaonweaj th Edison Coc:pany ,2-MAR 131972 l

cc: John W. Rowe isham, Lincoln & Beale f

Counselors at Law I

l

_ _ _ _