05000270/LER-1977-012-01, /01X-0:on 770927,primary to Secondary Leak Found Coming from 2B once-through Steam Generator.Cause Undetermined.Leak Plugged
| ML19317F329 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 10/07/1977 |
| From: | Ken Wilson DUKE POWER CO. |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| Shared Package | |
| ML19317F325 | List: |
| References | |
| LER-77-012-01X, LER-77-12-1X, NUDOCS 8001100704 | |
| Download: ML19317F329 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| 2701977012R01 - NRC Website | |
text
~
~
. f-Q v
DUKE POWER Ont!'A!W OCONCE Ut;IT 2 Report Number:
R0-270/77-12 Occurrence'Date:
October 7,1977
. Report Date: February 15, 1978 Facility:
Unit 2, Seneca, South Carolina Identifica' tion of Occurrence:
Primary-to-Secondary Leak through B
~
Once Through SteamcGenerator (OTSG)
Conditions Prior to Occurrence:
80 percent Full-Power Description of Occurrence:
' On September 27, 1977 air injector radiation monitor RIA-40 indicated a primary-to-secondary Icak of approximately 0.2 gpm.
Power was reduced to 67 pc.rcent to ' reduce powdex contamination. Subsequently, because of an apparently incrcasing Icak rate the unit was shut down on
~
October 7, 1977.. Af ter a 21 day outage and several unsuccessful attempts to find the leak the unit was -returned to power operation on October 28, 1977. A second unsuccessful attempt to-locate the leak was made from November,3 to 12, 1977.
On December 29, 1977 the unit was shut down to repair a-_ control rod stator, remove install.ed steam generator instrumentation 'and make -another attempt at 17 ocating the indicated leak.
b
.Tu e-77-25 was discovered to be leaking. Fiber optic and eddy-current examinations indicated a 90 circumferential' crack near.
the upper tube sheet. The tube;was stabilized and plugged.
The instrumented ' tubes (6), which showed considerable wall thinning, were also plugged A11 -(7) previously plugged tubes were re-plugged as a precautionary measure., Hydrostatic tests showed no further Icaks and the unit was-returned to power operation on January 16, 1978.
~.
Apparent Cause of.0ccurrence:
The exact cause of_tlue incident cannot be determined. The primary-to-secondary 11cak could have been _ caused.by either' tube 77-25 or any of the:seven replugged. tubes. The Nucicar Steam Supply System supplier, Babcock 'and Wilcox, and Duke Power Company are continuing to investigate the ' tube. leak problem. '
1 O
- - m 6
Gi J
f; s
'80.01100 ] o
DI KE l'O',il:R Co*tt'ANY OCONCE UNIT 2 (Cont'd)
Analysis of Occurrence:
All liquid and gaseous waste releasts were controlled and accounted for within applicabic criteria.
Plant personnel exposure totalled 11.48 man-rem.
The reactor coolant boundary was re-established by the tube repair. Therefore, the health and safety of the public were not endan-gered.
Corrective Action
Tube 77-25 was stabilized and plugged.
Previously instrumented tubes which showed appreciable wall thinning were also plugged. All pre-viously plugged tubes were re-plugged.
5 4
9 e
t 4.
.1 SUMMARY OF HAJOR OTSG TUBE EXPER1ENCE AT OCONEE~
.# TUBESLEXAMINED
- GENERATOR ROR. TUBE
. ELEVATION 1DATE TUBE. LEAKER CONDITION ACTION RO#
(excludes.. leakers)
LANE.
1-AL
'7 7 '
.17j Tubesheet
~10/31/76 Yes
'ths
. Crack Plugged
' R0-269/76-17 153 1-A 77 18 Tubesheet.
10/31/76 Yes-No
. Distorted Eddy Plugged Current Signal 1-B 114. 109-14th. Plate 12/8/76 No Yes No Visual
' Nailed-R0-269/76-19 139 Inspection 1-B 113 115 14th Plate 12/8/76 No No Distorted Eddy-Plugged Currant Signal 1-B 113 110 14th Plate 12/8/76 No No Similar to Nailed 114/109 1-B '
75 18 Tubesheet 12/8/76 Yes No 300 Crack Nailed
- 1-B
'75 12
.Tubesheet 1/15/77 Yes Yes 350. Crack Nailed R0-269/77-2
'140 1-B 81 128 Tubesheet 1/15/77 RNo No Eddy Current Nailed Indication 1-B 32 13 14th Plate 2/28/77 No Yes Eddy Current Nailed RO-269/77-8 3%
I.ndication 1-B 33 14 14th Plate 2/28/77 No No Eddy Current Nailed Indication 1-B 77 25 14th Plate 2/28/77 Yes No Eddy Current P.emoved Indication 1-B 2
7 13th Plate 2/28/77 No No Eddy Current Plugged Indication 1-3 2
8 13th Plate 2/28/77 No No Eddy Current Plugged
~
Indication 1-B 101 40 4th Plate 2/28/77 No No Eddy Current Plugged Indication
_ _1._
~
SUMMARY OF MMOR OTSG TUBE EXPERIENCE AT OCONEE (CONT'D).
- TUB'ES EXAMINED LANE l GENERATOR ' ROW, TUBE.
ELEVATION
- DATE TUBE LEAKER CONDITION ACTION
. ROP (excludes leakers) 1-B -
77-25 Tubesheet 3/22/77
.Yes Yes Weld Crack Replugged R0-269/77-11 100 1-BL
.77 3,5,8' ---
.3/22/77 Yes 1No Distorted Plugged Eddy Current
- - Signal 1-B.
77 15.
Tubesheet 5/7/77 Yes Yes Crack Plugged R0-269/77-16 507 Removed 5/7/77 Yes No 1-B
!77 ~
18 5/7/77
- - No
~No Distorted Plugged 1-B
' 17 5
Eddy Current Signal 2-B 77 23 Tubesheet 12/4/76 Yes Yes 270 Crack, Removed R0-270/76-15 133 Hole 2-B 77-27 15th Plate 12/4/76 Yes No Wear Appearance Removed 2-B 124 42 12th Plate 12/4/76 No No Eddy Current Flugged Indication, 40-60%
2-B 118 52 12th Plate 12/4/76 No No Similar to Left 124/42, 15%
3-8 77 11 15th Plate 7/21/76 Yes Yes No Visual Plugged R0-287/76-10 9
Inspection 3-B 77 19 15th Plate 2/14/77 Yes
.Yes Eddy Current Nailed R0-287 /77-2 142 45 Crack L3-8 77 12,13,14,15 2/14/77 Yes No Eddy Current Nailed 16,17,18,20, 21 3-B 75 2
2/14/77 Yes No Eddy Current Nailed
m CONEE'(CONT'D) k--
SUMMARY OF MAJOR OTSG TUBE EXPERIENCE AT O
'# TUBES EXAMINED '
(excludes leakers)
LANE ACTION
- - RO #
_. '..j
~
TUBE JLEAKER CONDITION ELEVATION DATE
- - GENERATOR'. ROW, TUBE q.
133 JRO-287/77-8' 3-B T78' 1
f15th Plate-' 6/10/77' No Yes. ~90 Crack 6-1/8" Nailed.
longitudinal B..
77 2
Tubesheet 7/14/77-Yes Yes 60 -90 ' Crack Nailed R0-287 /77-10
'120 Nailed' 7/14/77 Yes
.No 2-B
,77 25' Tubesheet 1/14/78 Yes Yes 90 Crack Nailed
' R0-270 /7 7 :3-B.
. 77 1-1/14/78-Yes No Eddy Current Plugged Indication, SOAK 2-B 75 - 21 Plugged 1/14/78 Yes No Eddy Current Indication, SOAK B 77 4
1/14/78 Yes No Eddy Current Plugged Indication, SOAK 2-B-77 18 1/14/78 Yes No Eddy' Current Plugged Indication, SOAK 2-B 77 19 1/14/78 Yes No Eddy Current Plugged Indication, SOAK 2-B 77 21 1/14/78 Yes No Eddy Current Plugged Indication, SOAK 2-B 78 4
Y e
O A
... +.N.nes w.-
- - m.
.eembaspee 4e p e -
=>w
= w
.ese
e. e a U. S. Nuct EAR n g cutAT OMY Ceuuse,e, icy EXHIBIT A N aC FOR*d y,4 LICENSEE EVENT REPORT 111H tettA s raWT OR TYPE ALL RECUIRED 14 FCAV AfiCW CcNTmot stocit: 1 I
l l
l l j@
4lll11111]@l j. lg 01 01 -1010101 010 l 101 0] @ 3 i
$7 0.A 7 se yCgt.sg tyrt JO lo lil in i e I n i elv 12j@16 JS UCt%gg nuassEM
) 7) 8]@
14 7
8 9 UCteette COQ (
l O I s i Ol0 1012 l 710.Ol_1 10 l O l7 17 I 7 ]@[0 3
73
..,r y o.n cose*T lolil Md Evt r e rt f
occ. r,,u n.
h ified as coning 3
EVENT DESCmFTION AND PRCS A8L$ CONSECUE**CESa primary-to-secondary leak wa e
e l_On September 27. 1977 down on October 7 for 21 days but the j
o 2 QJ 2] I f rom the 2B OTSG. ' The unit was shut was begun on j
Another unsuccessful shutdown l_ leak could not he located.
d stator the y
During an unscheduled outage to repair a control ro o 4 lo1511 November 3.
13 other tubes were y
1eak was located an (the Icaking tube was plugged.
(see
@l This is the 13th OTSG tube Icak at Oconee
@ l_niunood or renlunned.
h d by the repairs.
J i
attached). _The RC boundary was re-establ s e c
v.tv e su a..
stecces QJ a j 1 cces scaess c
c:ureusvt: ce I,c 1 c l@ l,Ej@ [u _J@ l 11l Tl E I X l Cl 11]@ W sistiu causs Cece cces coes 3
i.
- o aCYt tic 8e.
u i.
i OCCUAst%CE mtPCMT o s
.a
$20Vi=T1 AL coes n
h,"uarao !_avtur ve>a l-.-]
10 I 1 l 2l y
10l 1l W
[---j y
aircat =o.
2r
- s sa n
u j,y,,, L :.7 l 7l l
. e z.=w.t:x.. r.:mr
. x : m ::,,
u a
2
- s LE.,jhl.X3 LAdh L. Aj@
l 018l9 l 3 )
[lj@
[Lj@
(N_j@
In101115]@
: = @ a::
c r a.
u@
The corrective action,
=
m u
CAcss cesemencN ANocometenvt AcncNs g i The cause of OTSG tube leaks at Oconec is undetermined.
t d tubes.
Future g
the olunninn of leaking or previously instrumen e i l_taken was 3
i gj l_ action will be determined by research now in progress.
1 1
L1.LLI l-art I
E, CISCOVf RY OESCneFT1Gre l
- 34 0 R l A [_jhI_ Onor, tor Observat ion CTMEM TTATUS
%Po*E4 so ATVS l 01 81 d @ l___
'NA 3 lEj@ Srsvr tectrica ce.ett,se @
assovat oc acnvnv h i
8,jnvny c
=etresso o* = stress J
l s^
80 8 L2J@ L2!el
=
' ' eenscu 'e*6 xposO ts eticanevo= @
j l_016l9]@d@l_ Total exposure of 11.48 man-rem during t nas
=vuna
=
8 7
,1..c,. d'..uv'.'.,u
[
0tScmitt1CM esunsea m to fiTal l_ ni ol0j@l nA n
naCE To eaciuty I
4033 Cs om ca het Ct50p6p T10te llJ.2J t,_2J@l-ur-NAC USE cNLY j
liiiiiiiiiiii e
io fit 51 L.xl@7"3c,,ne;h33y,'"*"l Erel,,n,t i nn of unscheduled outanes I
(704) 373-8197 i
sauscrencrrasn_K. R. Wilson
, s cu,,
e ee is