ML20024B216

Reviews Current Events - Power Reactors, May-June 1976. No Action Required

ML20024B216
Person / Time
Site:	Crane
Issue date:	10/02/1976
From:	J. J. Barton, Toole R GENERAL PUBLIC UTILITIES CORP.
To:	GENERAL PUBLIC UTILITIES CORP.
References
TASK-*, TASK-GB GPU-2487, NUDOCS 8307070355
Download: ML20024B216 (11)

Text

<

..:...=-

~)

Cc P/4 AV$'7 MRf.

.c

~.

9' '

Z:3 00CUMErlT REVIEW

~

Plant / Unit E Hee The attached CB document has been reviewed for test progran and design modification requirements for the above Plant / Unit.

DOCUPINT:

Operating Experience, dated:

T Current Events - Pcwer Reactors, dated: Mw-Ju u e. l77(, (S-n-x)

Other

, dated:

Review of the attached document has concluded that no action is* required.

l f

,,.y W W fN tartup & Test Manager

• i.Date I

j l0-2 7f Test perintencent Date Review of the attached document has concluded that action is required by:

Problem Report (s) i has/have been issued.

Startup & Test Manager Date Test Superintancent Date W

07055 OISTRIBUTI0ti:

R.W. Heward, Jr.

W.T. Gunn E.D. McDevitt J.E. Kunkel H.A. talson R.J. Toole J.T. Faulkner File 415 8307070355 761002 PDR ADOCK 05000289

~ ~ ~ - -

.,S.

HOL

l a.----..-

\\

' wM.e:-mn...mw=:mwn.#e:=rmym=v &w=4)w%e;g;=:.q s.wm

==mym

~

p-n weMwcmwEw c smM@Ma=*:w % gG n

p p p si m s m m w m s e maa

=

1 ik '

C2 FIC pg -

M UNITED STATES D

• h CURRENT EVENTS NUCl. EAR REGUI.ATORY POWER REACTORS CoMM'ssioN

=

k E7ENTS SELECTED FROM REPORTS SU3MITTED TO THE UNITED STATES NUCLEAR REGUIATORY M

COMMISSION

=l l

1 i

MAY - JUNE 1976 Date, ablished 9/17/76 EMERCENCY DIESEL GENERATOR PROBL ES SURRY-1 A routine start of the emergency diesel generators from the control room of Unit 1 of the Surry Power Station damaged the nu=ber i diesel generator. The EDM-GM Turbo Vee 20, 3310 Bhp engine had a crack in #17 cylinder head which extended 1

between two exhaust valve seats and into the water jacket. The cylinder vall was ruptured, the piston broken and the connecting rod bent.

The cylinder head is an area of high heat stress and this was the most probable cause of the O

crack. The crack permitted water from the water jacket to drip into the cylin-j i

der. The engine had not been operated for twelve days, and this time frama allowed sufficient water to accumulate in the cylinder to form a hydraulic lock.

As the piston started the compression stroke during starting, the noncompressa-bility of the water caused the bend in the piston connecting rod and ruptured the cylinder wall. The broken piston resulted from the bent connecting rod allowing the piston to bottom out and striking the cylinder wall on the return

+.

stroke. The other cylinders were inspected and no damage or indications of water were found.

N The engine was repaired by replacing all daraged parts. The starting procedure 3-was modified to insure the diesel would be rolled with the cflinder test cocks open to check for flooded cylinders prior to =anual start.

About three weeks later, in preparation to start the nu=ber 1 emergency diesel generator, water was observed dripping from the air box drain. Inves tigation revealed water had entered the air box from #1 cylinder via th cylinder inlet ports.

W 07056 The crack in #1 cylinder head extended from an exhaust valve seat approximately thrae-fourths of the distance to the injector well and through to the water Jacket. The crack permitted water from the water jacket to drip into the cylin-der. The piston was near the bottom of the stroke which uncovered the air inlet ports and allowed water to enter the air box and exit the engine via the air box drains.

.a...._-.-.

l h

h m M wn-15 M m w n 22 w - m % @ M m e w w w e$m m eg T

EY,alc j#

s c

h$(( s 22 XOR M

w gp:5 The cylinder head was replaced. Because inspection af ter the last incident M6 failed to detect the cracked head, a = ore stringent inspection was conducted to 3

jfhf ensure no other cylinder heads of this engine were defective, ibh About six weeks later, during preparation to test the starting of nu=ber 1 e=ergency diesel generator, water was detected in #7 cylinder. The crack extended i

between the two axhaust valve seats and through the water jackat. Inspection i

of the engine prior to starting per=itted the detection of water in the cylinder

{ -

and prevented further da= age to the engine.

E

}

This was the sixth cylinder head on this engine to be found with a crack in a j

three =onth ti=e period. The location of #7 head on the engine does tend to i

eli=inate the presumed causes of either cylinder heat imbalance or heat stress as a result of an engine overheat.

It now appears that all failures were the result of a previous engine overheat condition that =ay have heat stressed the cylinder heads to a point where pre-t

=sture metal fatigue frea vibration is causing the cracks 'to appear between the exhaust valve seats. This is an area of high heat and vibrational stress.

To ensure reliability of this engine, weekly testing of the engine will continue.

New cylinder heads base been ordered and total replace =ent should preclude additional failures.

In each instance, the backup e=ergency diesel generator was de=enstrated to 2e operable. In addition, the =anufacturer's representative indicated that the nu=ber 1 diesel engine would have operated and perfor=ed its intended function had it been necessary, so no hazard to the safety er health of the general public exis ted.1-*

i DRESDEN-2 l

On March 17, 1975, the Diesel Generator failed to starr at Unit 2 of the Dresden Nuclear Power Statien and the diesel was taken out of service. During subsequent testing, the diesel again failed to start and the air start =otors were replaced and sent to the =anufacturer (Ingersoll-Rand) for exa=ination. No defect could be found.

nwy; On April 15, the diesel generator was being returned to service af ter repairs when the pinion gears and ring gear ja==ed.

No cause for the failure could be pinpointed.

Y 4

W 07057 am -

..-se

=

M---

,m-mi.

.. - -.. ~.... -..

hsdYe 4*d'- N"hakCgNak%.N NYd@I$$DkMNM@NiMee5NhD1' Mf -

- I -

J.kak=r*J *.e.-.%s h w deh '

N-

.if j

n.

u V

3-( The diesel generator failed to start again on June 4 after successfully starting for a monthly inspection. The diesel generator was then started successfully a tdtd nu=ber of times in an atte=pt to isolate the cause of failure. The diesel generator had started 12 times without incident when, on Tune 12, it failed to te start twice in four atte= pts. The same day, with a factory representative present, the diesel started six consecutive ti=es.

On November 14, vendor representatives were su==oned to the plant to exhaustively investigate the air start system. The ring gear was examined in detail and found to have two small, slightly gouged and burred areas. A series of 22 tests were performed, consisting of rotating the ring gear =anually and engaging the pinion gears from the control switch with the =ain air valved out, simulating an l

actual s tart. At the two gouged and burred areas, the pinion gears failed to engage three out of six times, while at all other points on the ring gear the tests were satisf actory.

The ring gear was dressed in these areas with a hone and file. No diesel genera-8+

tor starting failures have occurred since the burrs were removed from the ring gear.5 CRACKS IN REACTOR PIPING DRESDEN-2 An inservice inspection at Unit No. 2 of the Dresden Nuclear Power Station revealed an unacceptable ultrasonic indication in the isolation condenser i

safe-end. Removal of the 14-inch dia=ecer safe-end and subsequent dye-penetrant examination of the inside pipe surface confir=ed the existe.nce of the cracks.

3 The cracked safe-end was sent to 3accella Colt = bus Laboratories for =etallo-nt graphic analysis. This analysis revealed one circumferential crack at the 7:00 d

position and four axially-oriented cracks at the 1:00, 4:00, 4:45 and 5:00 positions. The depth of the circumferential crack was 0.261 inches, while the axial cracks ranged in depth from 0.255 to 0.300 inches. The circumferential crack was located approx 1rately 3/8-inch from the safe-end-to-pipe veld and was 0.60 inches long at the I.D. surface. The axial cracks ranged from 0.23 to 0.43 inches in length and extended to within 1/16-inch of the safe-end-to-pipe weld.

The metallographic ern*ntion revealed similar features in both the axial and circumferential cracks. They initiated at the I.D. surface and propagated intergranularly in the heavily sensitized microstructure. The fractured sur-faces showed no indication of chlorides, fluorides, sulfides, or other possible 7

corrosives. There were noderate residual stresses from welding and possibly from inner surface grinding (up to 5 mils of cold working were observed). The mechanism for cracking was intergranular stress corresion and has previously occurred at Unic 2 in the High ' Pressure Coolant Injection (HPCI) safe end, the 10-inch core spray piping, and the 4-inch recirculation bypass piping.

W 07058

,..m..

.i..-.

Fvs.+

GSYW W.=W

-4~

1;.=Eci-4 rn a

s

=

The unciad cracked isolation condenser safe-end was type 316 stainless steel.

It was approximately 5-inches long, with a 14-inch 0.D. at the piping end (0.56-inch wall thickness) and a 16-inch 0.D. at the no:zle end (1.08-inch wall thickness). The safe-end was furnace-sensitized during the post-weld stress if relief treat =ent of the pressure vessel.

The safe-end-is to be replaced with a forging of type 316L stainless steel.

The indications were not through wall and in no way affected system operation.

There was no effect to the health and safety of the public.

Also, a final report was received on the metallographic examination on the 10-inch dia=eter stainless steel core spray piping weld:ents at Unit 2.

The cracks were discovered in January 1975 and four of the eight welds were examined in detail by Argonne National Laboraccry.

g-Their report concludes that the cracks were generally circu=ferential and were located in the heat-affected zone near the velds. None of the cracks propogated y

3 through the welds, but were limited to a penetration of about 0.2 inches.

The mode of failure was strictly intergranular stress corrosion that initiated at l!

the inside pipe dia=eter surface and propagated toward the outside diameter.

I The corrective action taken to prevent recurrence was to replace the stainless N

steel portion of the core spray piping from the vessel no::le to ':he second 3

isolation valve with carbon steel pipe. The reactor vessel core spray safe-ends j

were replaced with tp'e 316L stainless steel with an inside diameter clad of 308L weld =aterial.5 I

OUAD-CITIES-1 A dye penetrant examination of the feedwater spargers at Unit 1 of the Quad-Cities Nuclear Power Station revealed one indication of cracking in each of two n

spargers.

The test was being performed, after a negative visual inspection.

l l upon request of the General Electric Cocpany, which was concerned over the 3

occurrence of cracking in several feedvater spargers of s1=11ar design.

The sparger crack indications were a 1.5-inch linear indication on the 60*

g sparger and a 2-inch linear indication on the 150* sparger. Both indications were through the junction box-co-ther=al sleeve veld.

E Af ter removal of the spargers, a dye penetrant examination of the inner bend f

radius revealed numerous linear indications on all four nozzles.

tions averaged two inches in length; the longest The indica-Maximus indication depth was 5/32 inch into the base metal. indication was five inches.

The najority of the L

i 1

1 W

07059

' l -} r '~" C~"~M~

' ' 7 '.'-~_._1~~J.~ ~ ~ ~ '-~~ -

~

~

- " ~ '^

- - g~opgam::ry$;Y552N t.w +mg

--. -. g

..m e_ g-

~,,.g &g M 74 4, fge'AER=5?@44.WS f5

. jib *T

$h

• 5

1. ^

.,.$5:$

MsgssNe

p;W~P h

• '. Segerg%

.;p h I r W* w m w N Ii p,$ x. 4 5 k$

M 2M M^

3W3 L

m p.tl5.

t. z :

v;eu m. v+ m w re-g _ h y W @ w n.w.w m-vrt M ef.vw &t.-~rP ri 2-es.,,j:yg.hpm wPc.g.:nser.

.u. >

n-ua s

4,F

-i

-S-indications were segregated on the upper half of the no::les. The cause of sparger cracking was attributed to fatigue caused by flow induced vibration, and compounded by stresses induced by inherent ther=al gradients between the feed-water piping and reactor vessel internals. Leakage between the sparger and the feedwater no: le contributed significantly to vibration of the sparger assembly and also imposed ther=al stresses on the nostle.

New feedwater spargers designed and manufactured by General Electric Company have been installed. These spargers have an interference fit to eli=inate leakage and thus reduce vibration and thermal induced stress cycling.

The safety implications of the event were minimal because the reactor was shut-down for refueling and although =inor cracking was present, the feedvater spargers and no::les were still capable of performing their designed functions.

There was no effect on safe plant operation nor on the health and safety of the public as a result of this occurrence.8 SMALL FIRE DURING CCNSTRUCTION During modification of an existing grating in the dr/well at Unit No. 1 of the Browns Ferry Nuclear Plant, veld slag f all onto a 16-inch I-beam inscalled on a 45-degree angle. The slag ran down the beam and ignited four lengths of breath-ing air hose in a plastic wrapper and an electric extension cord at an elevation j

17 feet below the welders. Ignition occurred af ter the craf tsmen installing the i

grating had lef t the area.

i The roving fire watch was notified of smoke coming from the reactor building in the vicinity of the TI? (Traversing Incore Probe) room. The fire watch was unable to find the source of smoke and called the control room to request operator assistance. Three operators arrived al=ost i= mediately and deter =ined the smoke was coming from within the dryvell. The fire alarm was sounded and the fire was promptly extinguished following the arrival of the fire brigade.

It was extin-guished by using dry chemicals and de beralized water. There was no damage or detriment to any system operating abiliry as a result of this event. This event will not cause delay in returning the Browns Ferry Units to service.

To prevent recurrence, the concurrence of a senior licensed operator or a certified Quality Control Inspector will be required when the fore =an deter =ines that a fire vacch is not required at the welding site. 3 a

ERROR IN FILING OF PL\\NT DR&*INGS C

t w,

.p 4:

./. e

'Jith the Cooper Nuclear Station at 81* power, one of 'the rea'ctor recirculation pumps tripped. This was the first trip of this type at Cooper and a check of the. control circuit indicated no malfunction, so a cause for the trip could not W

07060.

., ~

m m.~r:. w. g g;=-

• Q 3

?

?

?~r.:~

Mh".Q.

bW

.ww

%we,-em RAG y2t;;=

M. %

s A

be determined. About two weeks later, a second reactor recirculation pump trip occurred.

This time, the licensee found that a ventilation temperature switch i

9 was tripping fres vibration induced by a motor generator drive =otor.

The trip of the ventilation ta=perature switch caused the reactor recirculation pu=ps to trip. The te=perature switch was disconnected and was to be replaced by an improved type of switch.

During an unannounced inspection, the NRC inspector had planned to review the recent pu=p failures and asked one of the plant engineers to review the trip circuit diagram logic for the pu=ps with him. When the engineer began to ex-plain the circuit, he noted what he though was an error in the print. The drawing (Revision 11) showed the pump could be tripped by the te=perature switch and a lube oil pressure switch. The engineer believed there should also be another contact in the circuit to also provide a pu=p trip.

An identical drawing (Revision 10) in the engineering stick file did show another contact in the trip circuit. Examination of the pump trip circuit shewed the circuit to be actually wired in confor=ance with Revision 10 of the drawing.

The engineer and the inspector then attempted to determine the origin of changes in Revision 11 of the drawing. They found the above change and 14 additional changes on separste drawings had been transmitted to the licensee by the Archi-tectual Engineer (Burns and Roe, Inc.).

drawings were " approved for construction."The transsittal letter noted the The licensee's Docu=ent Control Depart =ent apparently processed these drawings as an "as-built" revision and placed them into the drawing system.

Revision 11 drawings had been intended to illustrate plant changes required for a modifica-tion planned for the fortheccing refueling outage. These drawings should have been clearly identified for " construction only" and should not have been placed in the drawing system.

The temaining 14 drawings that accompanied the transmittal letter will be re-viewed to determine if these drawings were also modified erroneously.

licensee will determine if other drawing transmittals were made which resulted The in drawing changes that were =ade in error. M INADVERTETT CONTAMINATIONS FIT PATRICK While acwing the lawn cri the eas sth $8pa u - 4 d e -, - 4 ~. %4

• n 7 og ege

' James A. Fttefatrick Nuclear Power Plant, the janitor discovered an area of ground that was especially soft, and vapors could be seen rising from the ground.

A radiation survey indicated readings above the background level.

W 07061

m

,a

- -- :_ g.

q...

- A backhoe was i==ediately brought to the area and the area was roped off. A s=all hole was dug and a sa=ple of water and mud were taken for analysis.

The source of leakage was a flange in a bondstrand pipe that carries water from a

che Waste Sample Tanks in Rad Waste to the Condensate Storage Tanks that are located outside of the Administrative Building. A sump pump was located in the area to keep the hole free of water so that repair of the pipe could be =ade.

The leak was repaired by replacing the section of bondstrand with type 304 stainless steel pipe. As a final solution, the entire length of bondetrand will be replaced with stainless as soon as practicable. The Architect / Engineer (Stone & Webster Engineering Corp.) has been requested to investigate all under-ground piping that does or could be used to transport radioactive water.

An estimated 1000 cubic yards of dirt will have to be shipped offsite for burial.

It was estimated that the total activity released from the time of discovery i

until the leak was stopped was 413 mC1.

It is highly unlikely that there was a significant release prior to excavation because there were no peripheral drains to transport the water directly to the sewer. Surveys of the lawn indicated no activity above normal background ten feet away from the. leak at the time of discovery.I1 k % s A L b ;. 7.:<,;;la-

[ [,/

t e.

CONNECTICUT YANKEE When the Haddam Neck Plant of the Connecticut Yankee Atemic Power Company was shutdown for refueling operations, a small through wall leak was discovered in the sump area into the safety injection cubicle. Nine days later, a second wall leak was noted coming.into the lowest level of the radwaste building.

Af ter an extensive unsuccessful search to locate the source of leakage, it was decided to investigate the vasta liquid steam generator blowdown discharge piping where it joins the service water effluent line. This required core drilling through the 12-inch reinforced concrete floor. The source of leakage was then identified as a fillet weld on the 24-inch service line that had eroded and was allowing leakage to the area below the dr"*ng room floor.

The waste discharge pipe directs steam generator blowdown and inter =ictent radioactive vaste liquid effluent into the service water discharge which even-cually flows into the discharge canal.

j With the change in steam generator chemistry control from phosphate to all volatile treatment, an increase in steam generator blowdown was required.

It is W

07062

)

i 1

-+

a gy**:xinP =4~ -.-w sn he.Q w ;

ffw.

W=wm=%=L..

cryMr w a f p ccQ 2g pl W ? W Nf "s.+ W;- mi.-m w w. w suhh?$#??lgp$?$$

CKste-

.5$="'3'$'k :

t"

• C: ~

?h ER

.O M

UW wg{ -

believed that this continuous blowdown of increased volu=e caused a rapid deterioration of the piping =acerial where the hot blevdown water contacted the relatively cold service water effluent.

~

f a repair consisting of a saddle and sleeve was welded over the defective areas.

The plant engineering group will evaluate a design that includes a heat ex-U changer to cool the steas generator blowdown to prevent ther=al shock and a

~

change in piping configuration which will place the piping connection above ground where it will be visible.

There was a release of radioactive tritium. Through underground seepage, the tritiu= found its way to the lowest point in the area, the contain=ent external g

su=p, and from there to the discharge canal. Sa=ples of the sud and water in the area of the leak showed the concentration of all ig limits of 10 CFR 20, Appendix 3, Table 1, colu=n 2. ',rsdionuclides within the j g EXPOSURES l

ZION 1 1

O ati

]I Two contractor personnel were working together reinstalling insulation at the piping elbou of a Resistance Te;perature Detector (RTD) line of Unit No.1 of the Zion Generating Station. They each were wearing film badges and indirect i

reading 0-200 =R pocket dosimeters. They were under the occasional surveillance

%g of a contract radiation protection technican, who was timekeeping to esti= ate g

accumulated worker dose. At the end of their shif t, both worker's dosimeters

[ ! d were found discharged. The ti=ekeepers estimate of dose recieved was approx 1:stely K

1 270 =ress and 320 mress, respectively.

1 l

l One film badge was sent for processing as a routine check of timekeeping accuracy. An exposure of 3,460 mres was indicated on the fils. Subsequently, the second worker's badge was sent for processing; the film read 3,390 mrem.

This brought their respective current calendar quarter whole body doses to 3,870 mress and 4,310 mrems.

A subsequent survey indicated a high radiation level existed only in a localired area near the piping albow. An adequate survey prior to issuance of a work permit and recognition of the potential hatard by requiring #a high range self-reading dosimeter sy have prevented the overexposures. U Point of

Contact:

\\

\\

Theodore C. Cincula Office of Management Information and Program Control U.S. Nuclear Regulatory Co ission W

07063

. p - ~: T z.: =- r- = -. =..... =r. :..... --

^-----~--

NMEN3?NIYNEMENNNE@@@@dEY7Ed

.r

_9-REFERENCES 1.

LER 76-04, Docket No. 50-280, May 12,1976.

2.

LER 76-06, Docket No. 50-280, May 27,1976.

3.

LER 76-10, Docket No. 50-280, August 2,1976.

4.

IE Inspection Report Nos. 50-280/76-6 and 50-281/76-6, June 11,1976.

5.

LER No.75-39A, Docket No. 50-237, April 13, 1976.

6.

LER 76-21, Docket Number 50-237, July 14,1976.

7.

LER 75-11A, Supplemental Report, Docket Nu=ber 50-237, June 29, 1976.

8.

LER Number 76-6, Docket Nu=ber 50-254, February 18, 1976.

9.

LER Nu=ber 76-5, Docket Number 50-259, May 20,1976.

10.

IE Inspection Report 50-298/76-04, May 12,1976.,

11.

LER 76-34, Docket No. 50-333, July 1,1976.

12.

LER Number 76-13, Docket Number 50-213, July 12,1976.

13.

IE Inspection Report Nos. 050-295/76-13 and 050-304/76-11, May 11,1976.

14.

Docket Number 50-295, April 29,1976.

e i

W C7064 i

i L._

~'

(

.. ~. - - ~ - - - - - - - - - - - - -

~'

o E$*T**~ % v ($.w$

GM5 s"

L W V* Y ?~fiM C 3 %. M.-y,;. W 3. Qw N

.Mr=, 4E --.. A.#--r-h f r~., 'n> c.7.4,C'WD. 3.~.n *.Q: tm.~~w LS 'b'li:

Myg -

WT A Q.sy.3N.a wi r A

y9

< = *#<Q&*N]*3-(hyse-QCm,.

T r4-e.'-

p y_; f

<m 4,,.f m,,,p",.,,_w y g.

-Q~?g r

,tQ

% hs m,s. ~ w e,Wrses,9y.n.;;5, e y te%e;.py%. p i,49: w, e,9,,,gt

^ r g ?**

~ y;rc c.yg[gg.* -

yw g..

. tow. % = & -.,1, g+

.v. _ _

y 3 g[q

s. g,

ga p ~..

zu

. m. f _g__

n W

-g r y :

N UNefEO STATE 3 f'_' ',]

F M

NUCLE AR stGu(ATOmv CCMutsSION

• ~i..,

PCST AGE AND PEES # AeQ W ASHINGTON. D. C.

20555 5

g CPPICI AL eussNESS esswsa r o e, c a==.**.o=

,a L

J

1. ENALTV PQ A petV ATE USE. 5300 m

Wc.

tr M

if W.'

h* ' '

j e-

+W n.<

EG w

1 7.h E

4 W

nt w

wW w

w.,k J%N 7 maarr v S T A Ril'D 5 Tgs7 u s u a f;g 3 h

['rRrtEimat pI'9 TIC Ur f L T Ties un e

~~-:

"IDDLt7rw oeyy3y,.VANT4 17057 e

fK

+

b D11 w.

D Si Ne 2

assa bye AJ n

-YM ir[

l

,i W

07065 a

1 4

l 4u

_ ph 6

• M

-_u