ML20107G736
| ML20107G736 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 09/19/1984 |
| From: | Carey J DUQUESNE LIGHT CO. |
| To: | Martin T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-02, IEB-79-14, IEB-79-2, NUDOCS 8411080230 | |
| Download: ML20107G736 (13) | |
Text
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- s T5hb Telephone (412) 393-6000 Nuclear Division P.O.Bor4
' Shippingport, PA 15077-0004 September 19, 1984
/D. S. Nuclear Regulatory Commission Attn: Mr. Thomas T. Martin, Director Division of Engineering and Technical Programs Region 1 631 Park Avenue King of Prussia, PA 19406
Reference:
Beaver Valley Power Station, Unit No. 1 Docket No. 50-334,l.icense No. DPR-66 Inspection Report 83-21 Gentlemen:
The referenced Inspection was conducted at our facility to determine the completeness of our actions taken in response to IE Bulletins 79-02 and 79-14. Two unresolved items remained open at that time pending NRC review of additional documentation.
Attached for your review is the additional information which was re-quested. Attachment I provides a summary of the bases for selecting anchor bolt stiffness values (83-21-01).
Attachment II addresses the use of representative pipe support stiffness values versus the actual pipe support stiffness values (83-21-02).
We believe that these attachments fulfill the requirements for the unresolved items of Inspection Report 83-21.
Very t ly yours,
. Carey Vice President, Nuclear Attachments
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8411080230 840919 PDR ADOCK 05000334 P
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B:avi,r Valley Power Station,' Unit No.1
' Dock:t No;'50-334, License No. DPR-66 Inspection Report-83-21 Page 2 cc: Mr. W. M. Troskoski, Resident Inspector U. S. Nuclear Regulatory Commission Geaver Valley Power Station Shippingport, PA 15077 U. S._ Nuclear Regulatory Commission c/o Document Management Branch Washington, DC 20555 Director, Safety Evaluation & Control Virginia Electric and Power Company
-P.O. Box 26666
.0ne James River Plaza Richmond, VA 23261 K. A. Manoly Division of Engineering and Technical ~ Programs Region 1
~631 Park Avenue King-of Prussia, PA 19406 9
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..% l f>A ATTACHMENTI
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SUMMARY
a FLEXIBLE 1 PLATE ANALYSIS DRILLED-IN ANCHOR STIFFNESS IE BULLETIN 79-02
~
.~The discussion that follows' summarizes the bases for the anchor bolt-stiffness.
used in-the structural analysis of base plates required to satisfy the requirements of IE Bulletin'79-02.
Anchor bolt stiffness used by Stone and Webster Engineering Corporation (SWEC) in the evaluation of flexible plates with ' drilled-in anchors is based on a review.
of actual-bolt. tension test data. Tension test data of drilled-in anchors was -
obtained from manufacturers of wedge and shell type anchors. This test data
-included bolt sizes from 1/2 inch diameter to 1-1/4 diameter, concrete strengths l' ' frorn 2000 psi to 6000 psi and variation in embedment length of anchors.
' Review of the test data indicates.a non-linear load deflection behavior of the.
anchors.
The appropriate stiffness to. use, the secant stiffness, was then calculated for the bolts over several load ranges.
For the purpose. of designj evaluation a single value of bolt stiffness, 250,000 lb/in was selected. This value'is larger' than approximately 90% of the secant
~ stiffnesses of all test samples in the range from 10% to 30% of the ultimate bolt-Leapacity..This range encompasses the design allowable loads for all sizes of both self-drilling' and : wedge type ' expansion anchors.' Use of a' larger than actual
-fEstiffness overestimates the prying action and therefore, represents a conserva-
.tive valuejof bolt stiffness for the entire range of the bolt sizes since it was selected to envelope,uwith the exception of the expected scatter in. test data, the secant stiffness.of all bolt sizes, embedment lengths and concrete strengths of interest.
b
- Attached are Anchor Bolt Stiffness Summary Tables I,:II, and 111. These tables provide additional informdion on which the 250,000 lb/in anchor stiffness is based.
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PHILLIPS PHILLIPS HIL Tl ANCHOR TYPE SE,LF-DRIL L WEDGE KWIK-BOL TS (1)
(2)
(3 & 4)
CONCRETE STRENGTH 235 2000 4000
>4000
<3500
>5500 fj (PSil p 2;
.10 Pult$ P 5.30 Pult 81 50 10 0 89 77 86 0"sg 43n Q
.30 Pult < Ft 5.4 0 Pult 100 100 100 10 0 90
-G0 yEh aU$
.4 0 Pult < P 5.60 Pult 10 0 91 10 0 100 95 NOTES:
1.111 PHILLIPS TEST DATA SELF DRILLED ANCHORS, PHILLIPS LETTER TO D. KEENAN SWEC DA1ED APRIL 16, 1979.
- 2. IT T PHILLIPS TEST DATA WEDGE TYPE, IEST DATA SHOREHAM SITE, PHILLIPS LETTER TO J. L ARLE AND A. RAPHAEL OCT. 25, 1977.
- 3. HILil KWIK-00LTS TEST DAT A.
TABLEI ABSOT A. HANKS REPORT NO. 8785 JAN. 30,1974.
- 4. HILTI KWIK-BOLTS SHEAR & TENSION TEST DATA, ANCHOR BOLT STIFFNESS
SUMMARY
ABBOT A. HANKS REPORT NO. 9059, APRIL 15,1974, 1/2" - 1 1/4" DIAMETER BOLTS orriNi.aons:
AT DIFFERENT STRESS LEVELS P
= LOAD ON BOLT AT WHICH STIFFNESS WAS MEASURED.
STONE & WEBSTER ENGINEERING CORPORATION Pult = ULTIMATE BOLT CAPACITY FROM TEST DATA ANC00tIAB1
PHILLIPS PHILLIPS HILTI ANCHOR TYPE SELF-DRILL WEDGE KWIK-BOLTS (H
(2)
(3 & 4)
I CONCRETE STRENGTH 2000 4000
>4000
<3500
>5500 i
fj (PSI) 55500 3
102.3
- 191.2
- 78.1*
88.5*
119.2*
12 7.4 *
[4h,-[
$m
.10 PuttSP 5.30 Pult j
15 9.8 308.1 78.1 138.9 191.7 18 8.3 i
- t; l
g p
73.0*
141.1*
131.7*
10 4.5
- 119.9*
l:
h
-j
.30 Putt < P :p,4 0 Pult
~
j 1 p
73.0 141.1 131.7 10 4.5 141.4 l
- vi z j
65.5*
124.4
- 29.6*
51.l*
101.2*
g
.40 Pult < P S.60 Pult l,
>gyg 65.5 13 8.8 29.6 51.1 109.5 NO TES:
i.
- 1. IT T PHILLIPS TEST DA TA SELF DRILLED ANCHORS, PHILLIPS LET TER TO D. KEENAN SWEC DATED APRIL 16, 1979.
I
- 2. ITT PHILLIPS TEST DATA WEDGE TYPE, TEST DATA SHOREHAM SITE, PHILLIPS LETTER TO J. EARLE AND A. RAPHAEL OCT. 25, 1977.
- 3. H!LTl KWIK-BOL TS TEST DATA.
ABBOT A. HANKS REPOR T NO. 8 785, JAN. 30,1974.
TABLE 11
- 4. HIL TI KWIK-BOLTS SHEAR & TENSION TES T DATA, ANCHOR BOLT STIFFNESS
SUMMARY
ABBOT A. HANKS REPORT NO. 9059, APRIL 15,1974.
j/2" I 1/4" DIAMETER BOLTS DEFINiilONS:
AT DIFFERENT STRESS LEVELS P
= LOAD ON BOLT AT WHICH STIFFNESS WAS ME AStlRED.
STONE & WEBSTER ENGINEERING CORPORATION Pult = ULTIMATE BOL T CAPACITY FROM TEST DATA 9
sNCHOITA02
.i I
HILTl KWIK-00LTS HILTI KWIK-BOLTS ANCHOR TYPE 1" DI AME TER 1 1/ 4" DIAME T ER 13 & 4)
(3 & 4)
CONCRETE STRENGTH 35 235
<3500
>5500
<3500
>5500 55500 fj IPSil
$5500 wez 1G 5.0
- 16 7.0*
72.3*
54.6*
63.5*
14 2.5*
"s'O5
.10 P"gg 5 P 5.30 Pult w
16 5.0 167.0 264.9 54.6 63.5 203.3 128.8*
- "z
.30 Pult < P 5.40 Pult
.Q[
~
~
~
~
m 128.6
~
E h[
47.1*
48.6*
36.0*
26.3*
35.6*
72.6*
h s
.40 Pult < P.S.60 Pult u t-p 47.1 46.6 36.0 26.3 35.6 72.6 D*
Uz
.60 Pult < P 5.90 Pult Wags
~
~
~
~
~
~
E Ny w J.
w
<w o
23.6*
36.6*
35.6*
26.4*
41.1*
51.7*
$$DM
.90 Putt <P5 Pult I
<um v 23.6 36.6 35.6 26.4 41.1 51.7
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I NOTES:
- 1. ITT PHILLIPS TEST DATA SELF DRILLED ANCHORS, l
PHILLIPS LETTER TO D. MEENAN SWEC DATED APRIL 16. 1979.
- 2. ITT PHit. LIPS TEST DATA WEDCE TYPE, j
TEST DATA SHOREHAM SITE, PHILLIPS LETTER TO J. E ARLE AND A. F APHAEL OCT. 25, 1977.
- 3. HrLTI KWIK-BOLTS TEST DATA.
ABROT A. HANKS REPORT NO. 6765, JAN. 30.1974.
T ABLE 111 l
- 4. nitri xWix-sotTS SHEAR & TENSION TEST DATA, ANCHOR 3OLT STIFFNESS
SUMMARY
l ABROT A. HANKS REPORT NO. 9059, APRit.15,1974.
1" - 1 1/4" DIAMETER BOLTS DEFINITIONS:
AT DIFFERENT STRESS LEVELS P
= t.OAD ON BOL.T AT WHICH STIFFNESS W AS ME ASURED.
STONE & WEBSTER ENGINEERING CORPORATION Pult = ULTIMATE BOLT CAPACITY FROM TEST DATA A, N C '; O L T A B 3
c ATTACHMENT II USE OF RZPRESENTATIVE PIPE SUPPORT STIFFNESS VALUES IN COMPUTER BASED PIPING ANALYSIS Required by IEB 79-14 Duquesne Light Company was requested in a letter (Mr. T. T. Martin of Region.I to Mr. 'J. J. Carey dated' December 2,1983) to determine the structural stiffness of 11 supports. The stiffness values detennined were to be compared to the values used in the piping analysis.
The stiffness values calculated for the subject supports are shown in Tables I and II. - The values shown are not exact as'is indicated in the note on the tables. - Exclusion of the effects described in the note was agreed to by Mr. J. Durr in a Telecon on November 7 with Mr. W. Falk of-DLCo.
We feel that the use of representative stiffness values for the modeling of pipe supports in the piping analysis of Unit I is more than adequate and is
.in'accordance with the calculational techniques that were reviewed in Boston by
~NF.C representatives in 1979.
The instructions as delineated in the 79-14 Bulletin specifically stated
- hat the effect of as-built conditions is to be evaluated with respect to the analysisL requirements "as described -in the FSAR or other NRC approved Documents".
J The NRC was at that time reviewing the pipe and support analysis methods used to satisfy the requirements of the IEB 79-07 (show-cause order). ' The ana-lytica.1 requirements agreed to for IEB 79-07 were used in addressing the IEB 79-14 ' concerns as required by that bulletin.
A discussion concerning support stiffness was included in the July 11, 1979 in5mittal concerning IEB 79-07. This is the only licensing. document that affects this issue. - The pertinent section of this submittal is shown in Enclosure 1.
As
.is delineated in this document, the use of infinite stiffness was one of the ac-ceptable methods for handling support stiffness along with the use of representa-tive values.
During the IEB '79-07 effort, the methods used to establish the adequacy of the safety related piping were re-evaluated and accepted by the NRC.
If it was felt that accurate modeling of support stiffness was significant with respect to safety, it would have been addressed during the Question and Answer phase of the
. bulletin', es acially since all the supports had detailed construction drawings on file at t1at time.
The methods of analysis used in addressing the 79-07 Bulletin were used without modification in satisfying the requirements of the IEB 79-14 because they constitute the definition of safety with respect to piping for Unit I.
Based on the above, we feel that since calculated support stiffness reviews were not established as an analytical requirement during the 79-07 effort, ~ f t was not necessary to re-evaluate this characteristic to satisfy IE Bulletin 79-14. The position that the as-built conditions were to be reviewed with respect to previously defined non-seismic plants stated in Revision 1 of the Y
79-14 Bulletin dated July 18, 1979.
"For older plants, where Seismic Category I requirements did not exist at the time of licensing, it must be shown that the actual configuration of these safety-related systems, utilizing 21/2" diameter piping and greater, meets design requirements."
Technically, we agree that the various parameters determined in a computer based analysis could possibly be affected by a change in the support stiffness used in the analysis. A review of the estimated stiffness values in Tables I and II shows that the stiffness used in the piping analysis is probably higher than the actual stiffness. The probable effects of this trend on the analysis would affect primarily the seismic and themal aspects.
The thennal support loads and stresses would probably be reduced with the use of more accurate support stiffness.
The modal. frequencies estimated for seismic analysis would tend to shift downward to lower frequencies.
If the modes that contribute significantly to a particular parameter are close to a peak in the ARS, the estimated quantity could be increased. Alternately, if the frequency of the significant mode was initially within the peak area, the results could decrease due to a reduction of the earthquake input.
The thennal and seismic effects oppose each other with respect to support loads because these loads are com-bined directly to detennine the design load of the support, thus minimizing the overall result.
The most significant effect will involve the piping primary stress check.
If the supports involving the area of maximum seismic response have significantly reduced stiffness, and if the frequency of the modes involved are close to an area in the ARS where a reduction in frequency constitutes an increase in the exciting ecceleration, then the estimated response would increase.
If this occurred in conjunction with the situation where the stress estimated previously was close to the allowable, then the code allowable might be excecded.
Considering the probability of all of these specific conditions being coincident, the overall probability of exceeding the allowable stress is remote.
The code design allowables are selected to encompass many variables. These include material manufacturing, construction NDT practies, design methods, maintenance procedures and uncertainties. We feel support stiffness effects are one of the uncertainties that the safety margins in the code address.
Another issue that should be considered is the inability to estimate accur-ate stiffness numbers.
Significant uncertainties exist in estimating support stiffness due to thennal clearances between the pipe and support, coupling effects (off diagonal terms in a 6 x 6 stiffness matrix), bolt stiffness variations (See Attachment I), base plate flexibility, etc.
These uncertainties render it almost impossible to develop an accurate flexibility value. Due to problems like this, it is more effective to design !nto the analysis and construction practice conser-vatisms that cover these uncertainties, and others. The writers of the subject codes have done just that.
It can be concluded that use of the analysis methods of Unit I result in an approximation of the actual stress. When the Unit I analysis methods, code allow-ables and construction requirements are considered in conjunction, what results are piping systems which are inherently conservative.
In conclusion, we believe that the Unit No.1 piping systems have been designed, constructed, analyzed and verified in a manner that assures that the allowable stresses of ANSI B.31.1 will not be exceeded during a seismic event of intensity equal to or lest, than the SSE and OBE values for our site.
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TABLE I Isometric Frame Type of Piping Analysis DrawingL Support Stiffness Stiffness Modeling Stiffness Number Number Restraint Type In 4 Analysis In #
83 VS-13 V
9.5x106 Man 1 x 106 83 VS-14 V
9.5x106 Man 1 x 106 1
83 R-17 L(2) 3.3x105 Com 1 x 106 B.
2.4x105 (2) 1 x 106 83 R-5 L
1.5x105 Com 1 x 106 NOTES:
1). Definitions V = Ver tical 1 = Direction 1 L = Lateral 2 = Direction 2 or two directions applicable T = Tranlation Man = Manual M = Moment
'Com = Computer 2).
The frame stiffness values shown are estimates only. They were developed by use of manual analysis or deduced from computer output from the STRUDL analysis of the support.
Effects due to bolt stiffness, coupling - (off diagonal terms in a 6x6
. stiffness matrix) thermal clearances, pipe wall. effects and base plate flexibility were not accounted for.
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..f, TABLE II Isometric Frame Type of Piping Analysis DrCwing Support Restraint Stiffness
. Stiffness Modeling Stiffness rumber Number Type In. 4 or In. 4/DEG Analysis In. # or In. 9/DEG 54 R-91 V+L 2.0x105(V)
Man 1 x 106 2.0x106 (L) 1 x 106 54 R-232 V+L 1.8x105(V)
Com 1 x 106 2.4x105 (L) 1 x 106 4
54 R-42 V+L 5.5x10 (V)
Com 1 x 106 4
6.0x10 (L) 1 x 106 5
54 R-43 V+L 1.1x10 (V)
Com 1 x 106 5
3.1x10 (L) 1 x 106 54 A-54 A
3.0x105 (T)
Man 1 x 106 5.7x105(M) 3.49 x 106 54 R-55 V
8.8x105 com 1 x 106 NOTES ' See Notes on Table I.
A l-ENCLOSURE I to
~'
ATTACHMENT II BEAVET. VALLEY POWER STATION, UNIT 1 REPOP.T ON THE REANALYSIS OT SATETT-RELATED PIPING SYSTEMS TOR BEAVER VALLEY UNIT 1 DUQUESNE LIGHT COMPANY ORIGINAL - JUNE 15, 1979 REVISION 1 - JULY 11, 1979 Stone & Webster Engineering Corporation.
Boston, Massachusetts
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BIAVER VALLEY POWER STATION, UNIT 1 Current rules allow two significant departures from the original techniques utilized on Beaver Valley Unit 1.
A.
An option is provided. for Upset Conditions whereby the anchor displacement effect can be considered in equation 9 along with deadweight,
- pressure, and seismic inertia effects or they may be combined with thermal expansion effects and evaluated under equation 10.
1 3.
For Emergency and Taulted Conditions, the codes require evaluation of only the primary portion (inertia effect) of the seismic loadings and do not require that the anchor displacement effect be considered, since it is secondary in nature.
Also allowed is a Taulted Stress allevable of 2.4 S, which was not stated in the Beaver Valley Unit 1 h
licensing documents; the equivalent value utilized was 1.8 S *h 2.
State how support stiffness is being accounted for in the current reanalysis effort and whether anything different from the original analysis is being done in this respect.
3-12 Revision 1 m
BEAVER VALLEY POWER STATION, UNIT 1
,e
Response
Roanalysis efforts are utilizing two programs, SHOCK 3 and NDPIPE.
If SHOCK 3 is utilized, supports and restraints are modeled in the manner of SHOCK 2 as rigid members, essentially allowing zero deflection in each restrained direction. When NUPIPE is utilized, representative spring stiffnesses are input in each restrained direction.
Consistent support stiffnesses are used for each problem.
3.
Provide the acceptance criteria used in the design cf the pipe supports, including veld and bolt sizing criteria, and indicate any deviations from criteria originally used (except criteria established in addressing ISE Bulletin 79-02).
Also, state your intention to comply, prior to facility startup, with IRE Bulletin 79-02 for all cases where loading on a pipe support increases as a result of the piping reanalysis and the support raevalu,ation indicates that any part of the support is not within the applicable acceptance criteria.
3-13 Revision 1 9