ML20002C871
| ML20002C871 | |
| Person / Time | |
|---|---|
| Site: | Big Rock Point File:Consumers Energy icon.png |
| Issue date: | 04/18/1974 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | Oleary J US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| NUDOCS 8101120246 | |
| Download: ML20002C871 (3) | |
Text
-
- g$b Regulatory Docket File e
993,'2.h[ h h%
C0HSumETS S
o.pMy POYlCr n%" ?Wsd" d'
" j C0mpany 3
,a nto ti
. APR221974
- i a " ' o" c :==
- a ~~a
^ - s
~~a " ~o'
^' cea e'7 788-osso R!CULATORY Watt SECTION April 18, 1974 Q.
DGCKET LERK g
fo CD Mr. John F. O' Leary, Director Re: Docket 50-155 Directorate of Licensing License DPR-6 US Atomic Energy Commission Big Rock Point Washington, DC 20545
Dear Mr. O' Leary:
This letter is written in response to an April 10, 1974 telephone conversation with members of your staff concerning the inverted rin problem in control rods at various boiling water reactor facilities.
The Big Rock Point reactor contains thirty-two (32) control rod blades. Sixteen (16) of these blades, designated Type-I blades, were inserted into the reactor in 1968. The manu-facture of these blades predates General Electric's manufacturing problems.
The other sixteen (16) blades, designated Type-IIA blades, were inserted into the reactor during the 1971 refueling outage. In order to determine the extent of the inverted tube problem on these blades, X-ray photographs of fourteen (14) of these blades were sent to General Electric for analysis. The results of General Electric's analysis are as follows:
a.
One blade examined 100%; no inverted tubes.
b.
Ten blades examined 50%; one inverted tube.
c.
Three blades' pictures unreadable.
A total of 384 tubes were examined in these blades which contain a total of 1,024 tubes. One tube was found inverted. These statistics suggest that there are two or three inverted tubes in the Big Rock Point control rod blades. It is also reasonably certain that no blade has more than one inverted tube.
It is our opinion that, in light of the minimal nature of the inverted tube problem at Big Rock Point, there is no effect on shutdown margin, the consequences of a rod drop accident, or the shape of the scram reactivity insertion curve.
ba31 8'/o//Ab ^%
.('
e 2
Mr. John F. O' Leary Big Rock Point April 18, 1974 With regard to shutdcwn margin, we have demonstrated at each of our last two refuelings the capability to maintain the core at least 0.3% Ak/k suberitical with any two adjacent rods fully withdrawn. This shutdown margin is well in excess of the requirement in the Technical Specifications for demonstrating 0.3% Ak/k suberiticality with one rod withdrawn.
We have found that the problem of inverted B c tubes in control h
blades, to the extent that it exists at Big Rock Point, does not con-stitute an unreviewed hazard either explicit or implied in the Finta Hazards Summary Report. Present shutdown margin checks are sufficient to detect any decrease in core shutdown margin and continued safe operation.of Big Rock Point is in no way compromised.
Yours very truly,
>~unh RBS/mel Ralph B. Sewell Nuclear Licensing Administrator CC: JGKeppler, USAEC
AEC DIS"IEUTION FOR PART 50 DOCKET MAT?~ T AL
)
(TE1PORARY FOPJ1)
~
CONTROL NO:_ 3531 FILE:
FROM:
DATE OF DOC DATE REC'D LTR lid 10 RFT OTFER Consumers Power Company J:ckson, Michigan 49201 4-18-74 4-22-74 X
R. B. Sewell TO:
J. F. O'Imary 1 signed SENT LOCAL PD2 X i: LASS UNCLASS PROP INFO INPUT NO CIS REC'D DOCKET NO:
XXXX 40 50-155 DESCRIPTION:
ENCLOSURES:
Ltr re 4-10-74 phone conversation, furnishing info regarding the inverted pin problem in DO NOT REMOVE control rods at various water reactors freilitie s.........
ACKNOWLEDGED PLANT NAME: Big Rock FOR ACTION / INFO-'MATION 4-23-74 GC BUTLER (L)
SCHWENCER(L)
V[ICiANN(L)
REGAN(E)
W/ Copies W/ Copies W/ 4 Copies W/ Copies CLARK (L)
STOLZ(L)
DICl2R(E)
W/ Copies W/ Copies W/ Copics W/ Copies PARR(L)
VASSALLO(L)
KNIGHION(E)
Wl Cvy ei, Wl Cuylea Wl Cuyle.
Wl CuyLeo KNIEL(L)
PURPLE (L)
YOUNGBLOOD(E)
W/ Copies W/ Copies W/ Copies W/ Copies INTERNAL DISTRTBUTION O m FTT O T5'CH REVIEW DALTON A/T IND vnEC PDR LM...DRIE CRIMES LIC ASST BRAIIPAN SALTZMAN OGC, ROOM P-506A W lIROEDER GAMMILL W IGGS (L)
B. IlURT M1UN121NG/ STAFF OMCCARY KASTNER GEARIN (L) dASE 64 NIGHT BALLARD GOULBOURNE (L)
PLANS GIAMBUSSO VPAWLICKI SPANGLER LEE (L)
MCDONALD M RE (L)(EWR) vST LO DWIRO R ED
)
IWO DEYOUNG(L)(PWR)
@ USTON MULLER SERVICE (L)
C. MILES SKOVHDLT (L)
NOVAK DICKER SHEPPARD (L) dOLLER(L)
ROSS Di1GHTON SLATER (E)
B. KING (E/W-358)
KLECKER P. COLLINS IPPOLITO YOUNGB' ^3D SM.TH (L)
EISENHUT DENISE d DESCO REGAN TEETS (L)
EG OPR DONG PROJECT LDR WADE (E)
FILE & REGION (3)
L4AINAS WILLIAMS (E)
/BENAROYA HARLESS WILSON (L)
MORRIS STEELF VOLIJfER EXTER'!AL DISTRIEUTION
/51 (f
N - LOCAL PDR Chaylevoix. Mich.
l W - TIC (ABER51' THY)
(1)(2)(10)-NATIONAL LAB'S 1-PDR-SAN /LA/NY l
d - NSIC(BUCHANAN) 1-ASLBP(E/U Blds,Rm 529) 1-GERALD LELLOUCHE 1 - ASLB 1-W. PENNINGTON, Rm E-201 GT BROOKHAVEN NAT. LAB
- P. R. DAVIS (AEROJET NUCLEAR) 1-CONSULTANT' S 1-AGMED(Ruth Gussmas)
- )6 - CYS ACES 2]CKZ2I3G SENT TO' LIC. ASST'.
W1 HER! ARK /BLUME/AGBABIAN Rt-B-12 7, GT.
4-23-74 DIGGS 1-GERALD ULRIl3CN.. 0:UIL 1-ED.. MULLER..F-309 G1 1-B & M SWINEBROAD, Rm E-201 GT
.