ML20058C762
| ML20058C762 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 06/28/1982 |
| From: | Hood A SPS TECHNOLOGIES |
| To: | Jackin I NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML20058C714 | List: |
| References | |
| NUDOCS 8207260441 | |
| Download: ML20058C762 (16) | |
Text
b Attachment F 4
l World Headquarters The Benson East Jenkintan Pentsi vania 19M6 d
L k!ChhiOLOGIES June 28, 1982 Mr.
I. N. Jackin U. S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL.
60137
Dear Mr. Jackin:
Accompanying ~this letter is a trip report covering a visit I made at the request of C. D.
Sellers of U.S.N.R.C.,
Bethesda, Md., in connection with technical problems relative to the installation of bolts at the LaSalle County Nuclear Generating Station on June 25 and 26, 1982.
The report covers engineering discussion and certain recommendations and a conclusion I drew after examination of the available evidence relative to problems presented to me.
Yours sincerely, T
SII R
A. Craigguvud, anager Advanced Metallurgical Products ACH/pml enc.
cc:
C '. E. Norelius - NRC C.
D.
Sellers - NRC 1
8207260441 820719 UN DR ADOCK 05000373 PDR
-. _m
Attachment F World Heacquarters The Benson East I-(
Jenountown Pennsvivania 19046 W
t 2issnoom itcwNotocits June 28, 1982
SUBJECT:
Visit to U. S. Nuclear Regulatory Commission Region 3 and LaSalle County Nuclear Generating station on June 25 and 26, 1982 This report covers the visit I made to the above locations on 6/25 and 6/26, 1982 relative to a problem regarding tight-ness of bolts on the area in containment and outside containment of the Unit one reactor.
I was contacted by C. D.
Sellers of the U.S.N.R.C.
on June 24 and asked to accompany him to U.S.N.R.C.
on June 25.
I had previously had discussions with Mr. Sellers on mechanical fastening technology at Bethesda.
SPS Technologies is a major producer of precision mechanical fasteners and offers consulting advice relative to fastener design and installation upon request from industry and government agencies.
I was initially briefed on 6/25 at the Region 3 office.
The problem is made up of two elements.
The first refers to an allegation that records relating to calibration of torque wrenches used at the reactor site may have been in error over a period of several months.
In addition, a check by one of the reactor inspectors of NRC of a valve attach-ment within a containment revealed two loose bolts that could be rotated with the fingers.
The second element related to the engineering implica-tions of the calibration errors and the loose bolts.
The first element will be dealt with by the NRC and Commonwealth Edison, the utility operating the nuclear station.
I will only deal with the second element of the problem.
The reactor is currently on zero power and is planned to be started up for the first time preparatory to going to full power on Tuesday, June 29, 1982.
A meeting was held at the LaSalle Nuclear Station at 1:00 P.M. on 6/25.
A copy of the list of those in attendance accompanies this report.
Also, an outline of the meeting subjects and information relating to the valves in the con-tainment area is enclosed.
Attachment F World Headquaders The Benson East 5f(
Jenkintown Pennsylvania 19046
- tcnr.otoo:ts a s s72.ao m
SUBJECT:
Visit to U.
S. Nuclear Regulatory Commission Region 3 and LaSalle County Nuclear Generating Station on June 25 and 26, 1982 1.
Motor Operator / Yoke Connection Tightness Check Quality Assurance management from C. E.
Co. said that all bolts in the subject valve attachments would be rechecked with a click torque wrench by turning the bolt head clockwise.
I suggested that a dial type wrench be used and that the data for each bolt be recorded in terms of the torque it took to get the bolt head turning.
Where the torque was too low, it could be brought up to the required minimum.
Where it was too high, it could be backed off and retightened to the proper value.
C.
E. Quality Assurance management agreed to do this for the 24 valves within containment immediately.
They agreed to do it for the approximately 125 valves outside containment within 6 months.
It was stated that many of the bolts were ASTM-A193-B7 (Cr-Mo 125 ksi UTS).
C.
E.
Engineering management pointed out that many of the bolts were only called out to be " wrench tight" while others had no upper and lower tolerance for torque.
After much discussion, C. E.
agreed to establish clamping load requirements for these joints and specify an allowable upper and lower torque range for each bolt.
Where certain bolts are not accessible l
with a torque wrench, C. E. Engineering and Quality t
Assurance indicated they would establish an engineering procedure and justify theit action.
I suggested that they could use a snug fit and an angle of turn as an alternative in inaccessible areas.
2.
LaSalle County Expansion Anchor Installation and Inspec-tion values This element relates to the installation of expansion-type anchor bolts in concrete at various locations at the reactor site.
Attachment F World Headquaners The Benson Eau 5
Jesntown Penns/ vama 19046 it(HNotocits 21s-sn.3 coo
SUBJECT:
Visit to U.
S. Nuclear Regulatory Commission Region 3 and LaSalle County Nuclear Generating Station on June 25 and 26, 1982 2.
LaSalle County Expansion Anchor Installation and Inspec-tion Values (cont'd.)
Mr. T.
Longlais, head of Structural Engineering for Sargent and Lundy made a presentation on their study of anchor bolt seating torques for these bolts.
Sargent and Lundy are the firm of architects and engineers used by C.
E.
Co. in the construction of the nuclear station.
Studies made of the torque, holding powen and slip characteristics were presented.
Copies of pp. 21-24 of a report on their findings along with Figs. 2.12, 2.23 and 2.24 were given to the group.
A copy is enclosed.
Their studies showed that once the expansion ring makes contact with the concrete inside the hole that further applied preload has little effect on the performance of the bolt.
They did establish a preload tension above that expected to cause slip and these are used in anchor bolt installation.
They also justified that a rechecking at 60% of installation torque is satisfactory and that bolts not achieving the 60% are taken to the original torque value.
I indicated that I had no problem with this engineering approach.
3.
Torque Wrench Calibration Accuracy (1 2% + 1 6%)
Concern was expressed by NRC personnel in the meeting that the errors discovered in the torque wrench calibration charts had contributed to improperly tightened bolts.
It is possible to determine two things.
First, the " worst case" of torque wrench effect on accurate torques can be established from the data and a recheck of the wrenches in question.
C.
E. Quality Assurance said they believed that maximum error was not greater than 11-12%.
Second, this worst case condition can be applied to a range of torque values acceptable to C.
E.
engineers for each joint in l
Attachment F World Heatuaders The Benson East Jenkintown Pennsytvania 19046 215 572 4 0 %
1KHNotoGl[5
SUBJECT:
Vist to U. S. Nuclear Regulatory Commission Region 3 and LaSalle County Nuclear Generating Station on June 25 and 26, 1982 3.
Torque Wrench Calibration Accuracy (cont'd.)
question.
C.
E.
Engineering management agreed to calculate the range of clamping loads and corres-ponding torque spread.
Any joint believed to be outside the acceptable range will be retightened after consultation with NRC Region 3 inspectors and engineering personnel.
I indicated that this procedure was acceptable from an engineering standpoint.
Meeting on 6/26 at NRC Region 3 Headquarters on the day following the meeting at LaSalle, NRC personnel from Region 3 and from NRC, Bethesda headquarters, met to discuss the results of the previous day.
It was the decision of NRC Region 3 personnel that they would request C.
E, to evaluate all joints in question as a result of the calibration problem prior to allowing the reactor to go above zero power.
I concurred with this posi-tion.
In conclusion, after hearing the engineering statements of C.E.
Co. and their consultants and after discussions with NRC personnel, I believe that all the actions the licensee has taken and plans to take, as set forth in this trip report, are in the right direction.
- f. W' s/
A. Craig ood, Manager Advanced Metallurgical Products ACH/pml encs.
6/28/82
Attachment F T.ARATTR COUNTY STATION COMMONWEALTHEDISONCOMPANT/NUCLEARREGULATORTCOMMISSIONMEETING JUNE 25, 1982 - 1:00 P.M.
PARTICIPANTS:
Nuclear Regulatory Comission (NBC)
NRC Consultants Cor:nonwealth Edison Company Sargent & Lundy Engineers 1.
Motor Operator / Yoke Connection Tightness Check 2.
LaSalle County Expansion Anchor Installation and Inspection Values 3
TorqueWrenchCalibrationAccuracy(1%+1%)
2 6
i Attachment F ATTENDANCE LIST CO.MPAN.Y: // A Tg'~ //s POCKET NO. 373 Date: /
ga IJ Pre-Inspection Conference OPost Inspectio.n Conference (Please N'AME (Please Print)
TITLE (Please Print)
ORGANIZATION Print)
////lff?%//
J/
5)d5m /s Alfff l-W
$.C[-od kRIUadbI hPSTedml.hw
- 00 She,,
Mac<.a c.,.
gc/n'nr/e
\\
_hhJnip aveusex,
,? v i <=.e.r a//A (1 A b$.&a y
y laJ. Sle.wsK r nov eA C / do o
-T E. CPU A v_. A SITE O A 50W_
C E C e>
2.G.fAL0
$ LT6 00NST, (UbR, (6 Co,
g a e e_ a o w e i re a A supeu.ua.
c e c.
> 6tw Cea L%
e som
%.J. % m f,.1 E ni J,g c ic->-
- 3. L. PA rv BI T MEM NoJ EuM-M /___
V. hum s tra.4.T% i.le.sc.
AumT t tv-ov
/a ib W-rs$l'$'"$1 T
b n e,/ f
?0' E% HGR C G~C o 8 Slu:
on
'L feti S Asci Ser L eD t-
.Q h,ksba,a feccL k natv
&c 2 RC h?
Aes?.
c,JG N RC G1 &
1 D. TIER A-E m d &> M anio k G., rsm.. f-hr NGO h. L. 3 b c.
Pro).Ccdc.SMSM.
Com. EcksuCo.
i h
4,
.*,e-.
,w
Attachment F Rx Containment Motor Operated Valves Tightness Check Basic Requirements - Manufacturers Recommendation Specific Tightness Requirements Non-Specific Tightness Requirements 1
1.
Torque Value g
g Standard Mech. Practice Standard Torque Chart 2.
Tightening Sequence (Wrench Tight)
Referral l
a.
G.E. - Atwood & Morrill a.
Anchor Darling Company b.
Anderson Greenwood b.
i i
Attachment F Rx CONTAINMENT MCHOR OPERA'IOR/ VALVE YOKE BOLTING TIGHTNESS REQUIREMENTS VALVE NUMBERS S&L SPEC.
MANUFACRIRER
'IORQUE SPEC.
TORQUE SPEC. REFERENCE 1B33-F023A J-2500 G.E./Atwood&Morrill 110 Ft.-Lbs.
Instr. Manual Part IX Step 12 IB33-F023B 1B33-F067A IB33-F067B
-red w/ John Chappell, IB21-FOl6 J-2938.01 Anchor-Darling Wrenchtight Instr. Manual w,.
A/DV Eng'g. G naget lE12-F009 lE51-F063 IG33-F001 1G33-F100 1G33-F101 1G33-F102 1G33-F106 LWR 179 LWR 180 IVPil3A J-2940 Fisher Controls Wrenchtight No Instr. Manual Reference; Info. Obtained From Glenn Hyatt 1
IVPil3B IVPll4A IVPll4B 1B21-F001 J-2950.01 Anderson-Greenwood 75110 Ft-Lbs.
Drawing #NO3-6492-500, Rev. B 1B21-F002 1B21-F005 lE12-F099A lE12-F099B lE51-F076 150110 In-Lbs.
Drawing #NO3-6498-510, Rev. C
Attachment F 2.4 Phase D - Anchor Preload Relaxation Tests O
2 4 t-tatrodoccio-When a concrete expansion anchor is installed, a preload will be induced on the anchor as a result of torquing the bolt or nut.
It is known that a portion of the preload in the anchor dissipates over a period of time af ter installation.
The purpose of these single anchor relaxation torque tests was to investigate the loss of anchor preload over time (relaxation).
The tests were performed on single anchors of varying types, and diameters, installed at various embedded depths and with various torques in concrete and mortar (Types N & M).
The specific testing requirements aie outlined in Table 2.4.
2.4.2 Test Apparatus Single anchors were installed in unreinforced concrete (no reinforcement within a minimum depth of ten anchor diameters) and in Types N and M mortar.
2.4.3 Procedure Single anchors were installed in concrete and mortar in accordance with manuf acturers' recocznended installation pro-cedures.
Installation torques are shown in Table 2.4.
The not or bolt of the anchors was loosened 1/8 of a turn and then retorqued to its original position.
The torque required to ree r=
the
=t er dott to it-ortsta t Po icioa a
cae=
O _ _. _.
_. _ _.. _ _. _. -... ~.. - - - - - -
Attachment F f
One recorded as a measure of remaining preload in the anchor.
anchor for each set of tests performed was tested with a load cell under the nut or bolt head to establish a torque-tension relationship.
The anchors were retorqued at intervals of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> s, 7 day s, 14 days and 28 days after initial instal-lation. The anchor load and the average anchor torque versus time were plotted for each set of tests.
(Figures 2.23 and 2.24 show typical load and torque plots.)
2.4.4 Results The results are represented by Figures 2.23 and 2.24.
The loss of preload at the end of 28 days was as little as 13% for O
a 3/4" diameter anchor embedded in mortar and as much as 54%
for a 1/2" diameter anchor embedded in concrete. Overall, it appears that less relaxation occurred for anchors embedded in mortar than for those embedded in concrete.
l i
! i
~ ~ ' ' ' ' ~ ~
~
'~~"w
-n wwen,,-_,,,,p___
Attachment F 2.5 Conclusions O
2.5.1 Phase A - Static Tension Tests on Single Anchors The static tension tests on single anchors have provided a a
clear understanding of the anchor behavior under loading and the effect of various parameters on that behavior.
It. is noted that the prestressing of the anchor at the time of testing does not affect the ultimate load carrying capacity of the anchor.
2.5.2 Phase B - Cyclic Test on Anchored Plate Assemblies The wedge, sleeve and shell type anchors tested in concrete O
and block walls exhibited insignificant anchor displacement when subjected to seismic 'or pipe transient loadings.
It can, therefore, be concluded that anchors embedded in con-crete can withstand cyclic loads up to 25% of manufacturer's ultimate capacity with a simulated OBE condition and 50% of manuf acturer's ultimate capacity with a simulated SSE con-dition.
It has been shown that anchors embedded in concrete block and mortar can withstand cyclic loads. The tests were conducted at load levels of 25% of the measured mean ultimate static capacity or greater.
It :hocid be noted that anchor preload is not required for the G
anchors to with s tand cyclic ' loading.
The preload in the V
Attachment F anchors te sted was generally not greater than 500 lbs. (0 O
V preload) which is equivalent to tightening the nut or bolt.
approximately 1/8 of a turn after " hand" tight.
2.5.3 Phase C - Static Tension Tests on Anchored Plate Assemblies The results of tests on a flexible base plate with four expan-sion anchors show that the, prying action is of the order of 15-20 percent of the applied load.
This increase is much lower than the expected increase in an assembly with regular steel bolts where the prying action force is calculated to be 110 percent. The reduc' tion in the prying action force is due to the e ffective lower stiffness of expansion anchors in-stalled in concrete.
- 2. 5.4 Phase D - Anchor Preload Relaxation Tests From the typical curves showing load or torque versus time (Figures 2.23 and 2.24), it can be seen that the anchor pre-load losses are most pronounced in the first 24 to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.
However, it should be noted at this point that the relaxation phenomenon should not be of great concern when viewed in light of the cyclic test results which showed that preload is not required to withstand cyclic loading.
O - _ - _ _ _ _ _
O O
O
(
(
Attacynent F l
7000-Anchor Type: Wedge Bolt Size: I/2 in.
Embedmont Depth: 4 in. (8D) g Erbedment Material: 5500 pai concreto O
Z 5000--
~~ '~~
o~
Average curve from 3 tests Preloaded v
i o
4000--
I O
Zero Preload 3000-
/
O m na
'/
Average curve from 4 tests 2E 0
's CD z
2OOO-t4 Approximate soit Preloaa Tension DS s s 4
I
$b t
w &
~
1 r
1000- l i
0-O O.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 ANCHOR
' S LI P (INCHES)
Fir,. 2.12 Initini portion of lond slip behavior for anchots wLLh dif ferent bolt pecionds
g..
.l.
g
.s.
i.
.I.
I..
.. o
.......l.
l.
1 m
r, g
....j p
o
.e a
ag
....... a3
.. i.
u e
.......... _......n..
m.
u a
....\\........
.........LD
- m.. _.....
. ~.
..[,
- a. _._..
.m
---..a.-
.p Q.....
.l.. _..... _... _...
-."n
.l
. t_ _.
r.
. l...
m _. _...
..p.
_~ _ {
.5 1
1
_ - - - + _.
.4.
a
- t 1
1
_.; m i
. _ _. ~ _.......
g._
i _
=,
__,4
~1 r
i 4
9
~
_..L_.=
J. ss __.
1 1
.ra_
1 6,
4
-,5 s.'
-....-.., t-...
. _. - - +
m.--
,,_p..
m.
- ~.
.. _ _M m.
g p.
a__
4
- i_
..... = _ _.
N
_ _p.._ _n_ _."_
c.
_ G
~
- ~ ~ ~
._.._.._..o.
u, <
. _ ':.~. :' '~
..y u.J nc
~
gg.
s__
c-i u_........_.i.._1......._...._o..
y4
.... _ s..
U_
-._ y
. ~... J.. ~. _ __. %,. _. _.... L. _ _. c-g-
(h g
. g__
g q-/-
-1 C
...._..__....._g._....,~..
.T_4.,_
t.-
-,a. _
-g 1
M. _ _ _. D.
~<
_..l.._...__;._=
._-=..I.~.'.
. _.4
. _- e,, _. I*-
-w
.~ _ _ _.
_m
.,..........J
-1 a.
- - ~
a
.._...s
._.6__.
4.-___.
H
.... u __
I_
1 r.. _.__
I
._ _..a..... _...
...J,..- _._ _....._--.. -. _
- i a.
- ~T
........,.....4......g..__....y.._
-4..-
_..C..._.._.
~
. _ >...._...._.3.,._~T._._._.
a 4,._
._..............__.y.._.,--
w_
4-
-... ~._
_ _ __ y-.... _... ~..
}..
......_3._-.
. ~. _ _
i.
.d.......
-.....x.__...
-.6......
h_
.y_.
.g._.
. In -
......._...._...g..._..7.._,_._._g._. - [._.
...........W.....g. _-D.
3.
I...
..g.
q...
.........l._...o..._..[...........g
... T _. __ _.. I _. - -
a _.-...-
[_... _......
._,.._.s 1
......t i
...._..a
-w_
l-
.i.--....._..
a
.3
.........o...D.-
.C
_._...i_........
s.
..-g
.._-3z.
....s......_j._...
..)
..... ~.....
- u.... 7.~... _-
.. ~..,... - - -..
.__...g~.....__....._..~.._--.....
.....o._.
.. ~
.g.
.r.......g............m.._....._
3.
2....
... D..
I
..M....
...C.
.....d...-.- *-*.-
.... g........b.
.. E. !.......I...........
.._,m....
..,s.
3 -
.a.
.I.......
.. l
. l
.a i
..g
.s
.s.
.... 1..
...tc
..-$.2.
.s
. rts
.. 7.
.. cu.
.s.
..T
...l....
...cu
.g..........
etT'
.... m.......i....... m
.m
.s.
.ta
.. m.
g
.s
,n s
......g.
...g; j
...a.
... m,
(.
.:. : L....
~
. :( SONnDd ). 0801. BDH')NU. :.i:.
r.
t.
e
g-
.s
.{
.l
...... I...
.. l..
O
.e.
....9.
3 e
l.
'T'
.a
..... 6
.l.
p........
/
V,,,
...l l
.l.
.cn i
..........a
. m..
.a Es.
.g.
y
.s m
.g C
>. ~.
qs y
. p.
.e W....
.C
...e...__...._
-.f N.
.... s.......
O
. _. _..I g
m
.g y
... e u
=
. _._ )
.....(
-.... g g;.
_...- _ 1
. +
f.,
r.-
- +
. _ _. 4
.. *l
...... ) _
i.
f..
--. N.
_ _ '.4
.gy l
q
.q
..~
6,.
.s
-1
. v; g.-
l i
r
_l.
L. _.
=.J.
n 1
5 a
-}
,l L
-l 6..._p
)
, 1 g
i
- 1
- 1__
g - - -;,
..o__
4'.,.._ t.,
.3
.h yp
- -),.
-.g c.
, c.
1
.s.
^
t l._
W
. ]~-
N.
m L.
t i
.l
.L,_"1,._
_I.
i
~...
4 1
i gy 1
i 1
g p'. _
t t__
a g._
,.,L..,
C,
... +.
. 9.~
3..__
,1 q.
.s 2'.6 4, _
1.
l t.
H C:
4,...
=,
g.. g.
n\\ %.
^I*
--8 E.D c
)
-r i___-
igQ
=
a..
64 p
[. -.
l t.,
I 1
'.s.
i
.l.
1~
.N l.
_1.._ __1 1
- l _._
I
\\-
.,v _. -. t.
> L. _
-- 9,
. \\_
_gg f,
-..r_..
y.
y-
- y. _.
y.
.~.[. _
. _ _s..-..._..,._
E e..--
.._.o-p
.._........s...
~. _.. _...
~.. _ - _ -.
.~. _ _-.... _ - -,x... - %. 3gg...
L
= --..._s,. s... _._-
- n. 4
~_. _..._,
.._....._..a_r.
.-......... ~
.._s._=.
--,.. _...p _ -..
(../j... _ _. --....... _...
r.
~.
,. ~..
,w.
s..=_~-.e
...._.e_.._._...... - _
.e.
..................~.,._..$---.--l
..-._t-(.-..._.
+I
-'_._-.l.~...
J'
.--../
,a.........
.._.l._-
_. _..,....~_...- -.
._.3..
. +......,
.s_...
W..... _.. _..._-...
1-
.....g..._..........._4._.
...................... ~.
.w....
_..7.
.......... i.........
...,._...s...
4
.l..
...-. m...
.. ~..
.................l......
f...
..4.s......#_......
....~..4-..-.._.... _......,
.e...
... w......:
.......l........._...
..........s........
-..........]
.. i _.
s s.__
.m...
.s.
.I.
a
+
.p.
..... l.
- i.....:
v.
s
.......i s
'C2 252**"* ~ ':52
.. a.
. G r3
. t5l*.
.La
......... ry....l
......l
..,.. vt.,..... :2'...... (T1..
I'...
tw
... La
.l..
g L
...... ( Q- -.].......-j,,.j j.. y- - -g.
g-i
.g...
g g g..
s s
--,,m,,.
.