ML20058K639
| ML20058K639 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 01/22/1975 |
| From: | Fiorelli G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Thornburg H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 9102130405 | |
| Download: ML20058K639 (5) | |
Text
,
scr rs xi txrativtbwmusdT $1' hYNTIfkT MtTCC 9 'k
-O hfir'? dr D R.]J t
l OIRECTOR ATE OF REGULATORY OPER ATIONS 1, '
/ '-
REGION lil
'o,%ss o' g 799 ROOSEVELT ROAD mm j
GLEN ELLYN ILLINOls 6o137 (312) s* s-2e6o January 22, 1975 H. D. Thornburg, Chief, Field Support and Enforcement Branch Directorate of Regulatory Operations, Headquarters DIRECTORATE OF REGULATORY OPERATIONS NOTIFICATION OF AN INCIDENT OR OCCURRENCE - MONTICELLO CRACKS IN 4" BYPASS PIPING The attached co=munication from the licensee covering the discovery of pipe f ailures in the A and B loop 4" bypass piping is forwarded with the reco=mendation that it be issued as a " Blue Sheet."
(
W G. Fiorelli, ief Operations Branch Enclosure As above R. F. k'arnick, RO:III Coordinator, RO:EQ cc:
J. G. Keppler, RO:III DR Central Files RO Files I
9102130405 750122 CF ADOCK 05000263 CF
No.
Date:
1/21/75 DIRECTORATE OF REGULATORY OPERATIONS NOTIFICATION OF AN INCIDENT OR OCCURRENCE Facility:. NORTHERN STATES POWER COMPANY
{
(MONTICELLO)
Problem:
CRACKS IN 4" RECIRCULATION PIPING r
The licensee informed Region III by telephone on January 21, 1975, that UT inspection of the 4" stainless steel bypass lines around the primary 3
recirculation pu=p discharge valves had been performed in accordance with R0 Bulletin No.74-10A dated Dece=ber 17, 1974.
Indications of circumferential cracks were found in three shop welds of pipe-to-elbows, upstream of the bypass valve.
Two of the indications were identified in Loop A,one in Loop 3.
The location of three defects is different from those identified in Dresden 2 and Quad Cities 2 described in DRO Notification of an Incident or Occurrence dated December 17, 1975, and December 24, 1974, respectively.
t The bypass piping layout at the Monticello plant is different from Dresden
}
and Quad Cities. Operations to date at Monticello have been conducted with the bypass valves open while the bypass valves at Dresden and Quad l
Cities were closed during operations up until recently.
~
i The following information was provided by the licensee:
1.
The unit was shut down on January 9, 1975, for a planned refueling outage.
While shut down, the inspection requested in R0 Bulletin 74-10A was performed.
I 2.
Ultrasonic testing revealed the following indications:
i a.
Two indications in Loop A at isolable piping-to-elbow shop welds upstream of the bypass valve.
(Attachment 1) b.
One indication in Loop B at an isolable piping-to-elbow shop weld upstrea= of the bypass valve.
(Attachment 2)
I 3.
The involved welds had been ultrasonically tested in November 1974; t
no unacceptable indications were detected at that time.
A comparison
{
of signal traces from the November 1974 examination with the current i
examination disclosed an apparent growth from acceptable non-linear indications to linear indications of up to 1/4 of the pipe circumference with crack depths of up to 1/4 to 1/2 of the pipe wall thickness.
4.
The licensee plans to RT the suspected crack areas January 22, 1975, and is currently reviewing corrective action.
I i
1 t
rt
..._=
4 I
t t
i i
i Action Taken by Reculatorv Onerations i
1.
RO:III followup is continuing and further RO action is contingent on additional findings and corrective action to be taken by the licensee.
I t
2.
A representative of the Minnesota State Board of Health was informed.
l i
1 Attachments:
I As Stated i
i 7
i e
4
)
h l
l
[
I I
[
c
---n-.
.._.2
,_..n
v To Get. Pump
^
Riser Header To-RER Syar,em t
1 REAJ-16 I
l p RBAJ-15 e REAJ-lh e REAJ-13
< ="
REAJ-12' I-Mo2-Sl4A.
h 4
/
b REAJ-1r f
r4 BBAZ-9 e
i bv'-
Lwear In dic.aticr35 RBAJ-7 dk
'R an u -s 4 Br.J 4,
y N HO2-53A REAJ -
RCAJ &
l Hecirculation.A.
Bypass Line Modified-Isometrie U Ret. 78K. 382-1. -
p,,
j f7 E[G Chhs esst j (c,,,e a.,,,)
.~
4 ADW13 t.
RFAT-12 RDW15 M2 2' Sk RBDJ b /1 6. Q.f N%
m
).
) -
nBu-1af~ r. M cr / C a t / C t?
i-
.see ib erf RB W 9 RBBJ-16 +
RD W 8
/
p RBfkT-17 "I-g-
,3335 c
RBBJ-19 REW6 i
L.
.RDW5:
e>
Recire.
RB E 3
' Loop "B" i-g l
i l
i RBlV-2
- O i-EI W
b7 Mo 2-53B
...c Feeirculation "B" Ironet.rie "N.
Ref. Dvs. FSKa383-2 Ret..G..E. 100. 13A.
A f ic.c h >a cnt 2
____