ML19339B324
| ML19339B324 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 03/26/1974 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Minnick L YANKEE ATOMIC ELECTRIC CO. |
| References | |
| NUDOCS 8011060744 | |
| Download: ML19339B324 (1) | |
Text
UMTEo STWES f
a e
(, Denscreanvr cr creucarcay c,cacy(gn,
. $,. g. 4 ATOMIC ENERGY COMMISSIO
/
/,
f.
.o cecogn o
(, [.7d '8 631 PACK AVENUE
\\
KlNG OF PRUS$l A, PENNSYLVANI A 19406 i-ll n
N 2 6 B74 I
(!
l' t
[;N-
$ :.gp F.
Yankee Atomic Electric Company Docket No. 50-29 Attention:
,Mr. L. E. Minnick Vice President 20 Turnpike Road b-Westboro, Massachusetts 01581 IEh L
V:
Centlemen:
E 1
The enclosed DRO Bulletin No. 3 " Failure of Structural or Seismic
-:I Support Bolts on Class I Components" is sent. to provide you with I
information reported by' Connecticut Yankee as an abnormal occur-
[..
rence at The Haddam Neck reactor facility.
s l
'1his information may have applicability at your facility (ies).
Action f
requested on your part is identified in Section B of the enclosed Bulletin.
[
c
- c Sincerely, e
~
}
@T/.k
[ James P. O'Reilly y
a Director f
1 Ericlosure:
F DRO Bulletin No. 74-3 p
cc:
Mr. H. A. Autio, Plant Superintendent
~'r-bcc:Jt$ FILES
, ~ " ' - ~ ~ '
/DR Central Files
~
PDR t
DTIE State of Massachusetts 2
h/)
=
l E
\\
i
- ~
omcx>
C 0 '.R
., by b,h 7)!..
sunnwe >
(
./26/.7.
om >
_,ro.. Asc-m g.s.3n Ascu me
""110o0797 q
lb I
t
(
)
t 4
[
1 Directorate of Regulatory E
h Operations Bulletin 74-3 I
j March 26, 1974
{
a t
E
' l~%-
FAILURE OF STRUCTURAL OR SEISMIC SUPPORT BOLTS ON CLASS I COMPO Fg I
+
y We recently received information from the Connecticut Yankee Atomic
{
g j
Power Company, describing bolt f ailures found during routine in-service i
inspections at the Haddam Neck pressurized water reactor which may relate to the installation and serviceability of seismic support bolts
}
g or other seismic support structures at your facility.
r g
[
u[
Description of Circumstances a.
L During a visual inspection, several steam generator seismic support holddown bolts were observed to be loose.
Subsequent inspections lj A.
@4.
by ultrasonic and impact testing of all 256 bolts identified a
.e 2
g total of 24 which had f ailed and were unable to perform their de-h A preliminary evaluation indicated the bolts had sign function.
2 failed in tension apparently from over-torque during the original j
It was later ascertained by metallurgical and elec-
[
installation.
tron microscopic techniques that the failures were the result of 4
stress corrosion, associated with the high pre-etressing, stress t
j risers at the root of the bolt threads and the presence of moisture i
f originally from the concrete and continuing from miscellaneous
{
spf,11s, Icakages or high humidity commonly found within containment f,
I areas.
k In reviewing this problem it was noted that Section XI of the Boiler and Pressure Vessel Code does not specifically address the J
inspection of support structures for vessels except for the
" support attachment (vessel support skirts) which includes the
+
velds to the vessel and the base metal beneath the weld zone and along the sup/ port attachment for a distance of two base met thicknes s."l and pumps within the system boundary "whose structural integrity is
?'
relied upon to withstand the design loads and seismic induced
]
displacements" are subject to examination.2/
4 i
B.
Action Requested 1
Since the various support structures for vessels within con-0 1.
tainment are subject to the same environment as other support structures described above, but are not subject to the same a
v 1/ASME Boiler and Pressure Vessel Code;Section XI; Table IS-251:
Para. H.
i 2./ Ibid; Para. K-2.
1 l.
ugen m Up 5'5
=
ew==.
-.--gr e. -w,.,.g. r....
~
- .4
m 1
- \\
('
l r
'}s '/
e
/
F di E
i hg examination, it is requested that during your next scheduled I
outage, you selectively examine a representative portion of
]!
the vessel support members and structures, including the bolting material for twa Seismic Category 7. vessels (as de-
[L j
N --
W((
fined in Regulatory Guide 1.29) whose structural integrity is i
relied upon to withstand design and seismic displacements.
Q This examination should include sufficient coverage of each 1
L support structure to provide confidence of serviceability.
(
L-
];
2.
It is requested that you notify the R0 Regional Office in
)
?
writing within 20 days of your proposed schedule for this a
1;j inspection including the date that your detailed written k
programs and procedures will be available for RO inspection.
(,
Your program shall include, but not be limited to: structures t;
j to be examined; inspection methods to be used; and number of
}
'A bolts per structure examined.
D
.y p.
J 3.
If failures are revealed during your inspections, you are Y,
instructed to promptly report these as " Abnormal Occurrences"
[f f
in accordance with the requirements of your license.
-g
'io
's Yv D
t.
e Y
b g
i a
I' I
w-k
\\-
d ei;4 Y
j r
i}
-- v:;
~ ny---- : - -,-
r -- ; v ~ ~.-
m.-,,..~_..,
.