ML17037C142

Letter Reporting an Incident, During Radiography and Ultrasonic Testing, That Disclosed a Series of Cracks Extending Around the Upper 180 Degrees of the Inside Diameter, Exist in the Stainless Steel Safe-End of the Core Spray..

ML17037C142
Person / Time
Site:	Nine Mile Point
Issue date:	03/10/1970
From:	Burt P Niagara Mohawk Power Corp
To:	Morris P US Atomic Energy Commission (AEC)
References
Download: ML17037C142 (8)

Text

4g%

+Pl '

t p E4 USAEC MASH US GOVERNMENT k~)LRKl MF ATOMIC ENERGY COMM HDQTRS 19705(hA l0 pg g g) 4O

'V.S. ATOHfC EN)RGY COMM.

N M 9MILE OStl T)YX'uillT ~ Yg

%710-547-0657 3"10-70 '%00 PM EST ATTENTIONX DR PETER " . p 9

DIVISION OF REACTOR LICENSING +ffjp, GENTLEMEN' /gN lq ~

SUBJECTS DOCKET NO. 50"220, "P ~ Oi Le XDPR- 17 I

RADIOGRAPHY AND ULTRASONIC TESTING ON MARCH 8 1970 DISCLOSED THAT A SERIES OF CRACKS EXTENDING AROUND THE UPPER 180 DEGREES bF THE INSIDE DIAMETERS EXISTED IN THE STAINLESS STEEL SAFE-END OF THE CORE r

SPRAY NOZZLE LOCATED AT AZIMUTH'40 DEGREES OF THE NINE MILE POlNT NUCLEAR STATION REACTOR VESSELS TMO VERY SMALL LEAKS MERE DETECTED SEVERAL DAYS PREVIOUS 'UHICH LED TO THE APPLICATION OF NON-DESTRUCTIVE TESTING+ UHEN DISCOVERED~ THE REACTOR HAS OUT OF SERVICE IN A COLD

'I

'SHUT-DObN CONDITl ON,

I* 4I 4 IT IS

.-nkvd'-- X'tl~.>W

~ s' ' 'l'p c p a >.,s%tg 't p NECESSARY TO REHOVK THE EFFECTED NATERIAL OF THE SAFE"END FOR HETALURGICAL EXAHINATlON AS SOON AS POSSIBLKe THEREFORE'HE HATER LEVEL IN THE REACTOR VEST BE LOL'JERED TO FOUR FEET OVER THE ACTIVE FUEL+, THIS ALLOt'JS A THREE-INCH CONTROL BAND TO THE INVERT OF THE CORE SPRAY NOZZLE ~ TECHNICAL SPECIFICATIONS 2 ~ 1 ~ i XW, PGe 6 DO NOT PERY)lT LOt'JKRING TO BELOW'EVEN FEET ELEVEN 'INCHES OF NOld<AL LEVEL.

THIS CORRESPONDS TO FOUR FKKTq EIGHT INCHES ABOVE TO TOP OF ACTIVE FUEL. %SEE BASES PG ~ 9%+

THEREFORE~ t'JK'EQUEST A TKNPORARY CHANGE IN TECHNICAL SPECIFICATIONS TO ALLOtJ LOUERING TO FOUR FEET ABOVE ACTIVE FUEJ. t'JHICH IS ELEVATION 294 FEET. Ig ORDER TO ASSURE CO@)PLKTK SAFETY'HE FOLLOWING'TEPS UILL BK TAI<ENX tJATKR LEVEL N, HANOHKTL'R LOOP ESTABLISHED TO OUTSIDE DRYtJKLL READABLE SEVERAL FEST ABOVE AND BKLOiJ REQUESTED LEVEL HONITORED BY OPERATOR X UI)H CONY)UNICATIONS TO CONTROL ROON.,

X, CLOS D CIRCUIT UNDERWATER TYPE TELEVISION,IN VESSEL AT WATERLINE MONITORED 'IN CONTROL 'ROOH.-

743 I I. <XPOSURK

4 )

Z.

II W

>>1A R'FVEL' 'f '1v' Fxi.'-"'u ~-;

II EXPOSURE OF 105 R/HR bILL EX>>IST AT VESSEL-FLANGE ~ REGULAR CONCRETE FLOOR SHIELD PLU'GS bILL BE .REINSTALLED ABOVE VESSEL ATTENUAT'INC'IELD TO FsZLOt'00 NR/HR ~ THE FLOOR. AREA.[~JILL BE DECLARED A HIGH-

,tADIATIGN ARFA -ANB ACCESS RESTRICTED. 'XPOSURE LEVELS i')ILL BE 1

SLO'>>'EELY t'MONITORED AS 'EVEL IS LOUERED IN VESSEL ~

AREAR'RESENTLY EnPQSU2Z IN THF UORK AT 27 NR/HR GN COt<'i ACT ViLL B~

i AI~:T,>I"ZB AS LOU.AS PR>>ACTICAL <iITH LEAD SHEET SHIELDING INSIDE THE VESSE1.

III'ONTROL GF LEVEL LGl" INTO THE VESS L FRGH THE CONT OL ROD DRIVE SY$ TEii IS ABOUT 65.

GPY ~ BR>>AII~AGE TO HGLB LEVEL IS AT PRESENT AND WILL BE iiAINTAINED THROUGH R>>EtlOTELY OPERATED" VALVES BET>iEEg THE CLEAN-UP SYSTEti AND ZITHLP CGtJDEiv'SER OR EQUIPhEHT BRAIN TAN<< ~ OPERATION IS FRGY> THE CONTROL R>>00tl ~ ONE OF THREE CONDENSATE PUHPS GILL BF, IN" CONTINUOUS OPERATION UHEREBY CONDENSATi". CA'N BE ADDED TO THE VESSEL BY REhOTE FEED>>~ATER VALVE OPERATION FROM THE CONTROL ROOtio IV+ HEAT RLYiGVAL REGULAR hEAT REtiGVAL SYSTEYiSp REACTOR CLEAN"UP ANB/OR SHUT-D04N COOLING <lILL BE AVAILABLE AND IN SERVICE IN THEIR tqGRl>>iAL- OPZRATIivG iiIOBZS.

I h(

ll C

U f

't I

1

UPON CONPLETION OF PIPE CUTTING OPERATIONS AN EXPANDABLE PIPE PLUG HILL,BE INSERTED IN TPE NOZZLE AND RE1NFORCED <~JITH JACK SCREl>S FROH THE OU7SIDE iN ORDER TO PREVENT THE PLUG FROID BEING BLOt'JN OUTo 4ATLR LEVEL UILL THEN BE RETURNED TO A POiNT NEAR THE FLANGE READABLE I

OiN CLOSED CIRCUIT'ELEVISION AS AT PRESENTo LEVEL hAY BE INCREASE'D TO REFUELING LEVEL SHOULD INVESTIGATIONS SH04 'NEED. FOR CORE UNLOADING~

RESULTS Oi'HETALUR'GICAL,EXAMINATION UILL DETERt'1INE METHOD OF REPAIRp

.BUT IN NO EVENT KILL REACTOR BE. OPERATED UITHOUT PRIOR NOTICE OF U o So'TOl'1IC ENERG7 COHYiiSSIONo /

/

INVESTIGATION OF ALL OTHER SAFEENDS ON VESSEL ARE PROCEEDING bITH P ~ To p UoTo p AND R ~ To HETHODS ~

P. ~ A~ BUiRT STATION SUPERINTENDENT N I~i 9NILE OSLJ

u1 l o vl at<v

~ s "QQG3 p.",:, -'.,:'Q>V'8".

eg a e T i> uvAOE6~

N01103S 3',l",'i."..S '11VN SU3lHVAAV~H al ~r p %p