ML16340C978
| ML16340C978 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna, Diablo Canyon, San Onofre, 05000000, Zimmer |
| Issue date: | 09/30/1982 |
| From: | Vollmer R Office of Nuclear Reactor Regulation |
| To: | Eisenhut D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML16340C979 | List: |
| References | |
| NUDOCS 8212030265 | |
| Download: ML16340C978 (12) | |
Text
A T
tWEI RECU ci P0 UNITEDSTATES V)~ NUCLEAR REGULATORY COMMISSION Ql i)>
'ASHINGTON, O. O, TG555
~l"- pA III September 30, 1982 MEMORANDUM FOR:
Darrell G, Eisenhut, Director Division of Licensing FROM:
SUBJECT:
Richard H. Vollmer, Director Division of Engtneeri'ng ALLEGED DESIGN DEFICIENCYPOTENTIAL BOARD NOTIFICATION ITEM An alleged design deficiency in ASME Code Class 1 piping which is discussed in the.attachment letter to Chairman Palladino was brought to our attention by the NRR Director's office.
The concern in this allegation is that the effects of cvocal pipe wall stresses, due to support loads introduced by pipe clamps, are not being evaluated properly.
This concern potentially relates to all plants (BWR and PWR) currently under OL review, but to our knowledge it is not the sub]ect of any con-tention in any operating reactor hearing.
It is NRR's experience, as gathered from our own audits on NTOLs and from the Independent Design Review Program, that the effect of support reactions on piping is being considered by system designers.
Specific support and piping design criteria are coIIIIitted to by all applicants; however, the level of the NRR review does not generally address pipe clamp details unless in-spection during construction raises questions, The magnitude of the problem discussed in the allegation has not been
- assessed, and, in fact, without more precise information regarding the exact nature of Mr. Van Meter's concern, we would not be able to make such an assessment.
We expect that we will be assisting the Office of Investigations in evaluating the significance of the allegation.
A complete failure to deal with the pipe support-pipe interface design
- issue, as implied in the enclosed letter, would be a.Serious matter if substantiated.
As this information appears to meet the guidelines of Office Letter No. 19, we reconmend the licensing board be notified.
Enclosure:
As Stated.
Richard H. Vollmer, Director Division of Engineering
( saiaOSoaw5 8211am PDR ADOCK 05000275 P
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~ io~L. vous.l l.4vscsq tnc wall thickness of the pipe shaU bc incrcpsed, or, ifthis is impractical or would cause excessive local stresses,
'the superimposed loads or other causes shaU be reduced or eliminated by other design methods.
NB-3620 DESIGN CONSIDERATIONS NB-3621 Design and Serricc Landings The provisions of NB-3110 apply.
NB-3622 Dynamic Efccts NB-3622.1 Impact. Impact forces caused by either external or internal loads shall be considered in the piping design.
NB-36222 Earthquake. The eff'ects of earthquake shaH be considered in the design of piping, piping
- supports, and restraints.
Thc loadings, movements (earthquake anchor movements),
and number of cycles to be used in the analysis shaH be part of the Design Specifications.
Thc stresses resulting from these earthquake efects must bc included with weight,
- pressure, or other applied loads when making the required analysis.
NBQ6223 Vibration. Piping shaU be arranged and supported so that vibration wiH be minimized. The designer shaU be responsible, by design and by observation under startup or initial service conditio s
for ensuring that vibration of piping systems is within acccptablc leveh.
NB%62".4 Rclicf and Safety Valve Thrust. The ctfccts of thrusts from relief and safety valve loads from prcssure and tlow transients shall bc considered in thc design of piping, pipe supports, and restraints.
See Appendix O.
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HB-3623 Weight Effects Piping systems shall be supported to provide for thc elfccts of live and*dead
- weights, as defined in the
~,
fallowing subparagraphs, and they shall be arranged or properly restrained to prcvcnt undue strains on equip mega.
NB-3623.1 Live Weight. The live weight shall consist of thc weight of the Quid being handled or of thc Quid used for testing or cleaning, whichever is greater.
-36%2 Dead Weight. Thc dead weight shall consist of the weight of the piping, insulation. and other loads permanently imposed upon thc piping.
NB>>3624 Thermal Expansion and Contraction
~
Loads NB-3624.1 Loadin~,
Displaccmcnts, and Re-straints. The design of piping systems shaH take into account the forces and moments resulting from thermal expansion and contraction, equipment dis-placcments and rotations, and thc restraining c~ects of hangers, supports, and other localized loadings.
0 ND-3000
'NB-3624.2 Analysis of Thermal Expansion and Contraction Effect. Thc analysis of thc eflccts of thermal expansion and contraction is covered in NB-3672.
NB-3624.3 Provision for Rapid Temperature Fluc-tuation Effect. Thc designer shall provide for unusual thermal expansion and contraction loads caused by rapid temperature fluctuations.
NB-3625 Stress Analysis A stress analysis shall be prepared in sufiicient detail to show that each of the stress limitations of NB-3640 and iNB-3650 is satisfied when the piping is subjected to the loadings required to be considered by this Subarticle.
NB-3630 PIPING DESIGN AND ANALYSIS CRITERIA (a) The design and analysis of piping when sub-jected to thc individual or combined eflects of the loadings defined in NB-31CO*and NB-3620 may bc performed in accordance with this Subarticle. Design for pressure loading shall be performed in accordance with the rules of NB-3640. Standard piping products that meet the requirements of ANSI B16.9 or NB-3649 satisfy the requirements of NB-3640, and only the analysis required by NB-3650 need be performed.
(b) Within a given piping system, the stress and fatigue analysis shall bc performed in accordance with one of thc methods given in NB-3650, NB-3200, or Appendix II. Stress indices are given in NB-3680 for standard piping products, for qome fabricated joints, and for some fabricated piping products. Some piping products designed for pressure by applying the ru)es of NB-3649 may not be listc;d iq NQ-3680. For such'roducts, the designer shall determine thc stress indices as required in iNB-3650.
(c) When a design does not satisfy the requirements of NB-3640 and NB-3650, the more detailed alterna-tive analysis given in NB-3200 or the experimental stress analysis of Appendix II may bc used to obtain stress values for comparison with thc criteria of NB-3200.
(cl) The requirements of this Subarticle shall apply to all
.lass 1 piping except as exempted under (1) or (2) b iw.
tl) Piping of 1 in. nominal pipe size or less which has been cfassified as Class 1 in thc Design Speci-NBQ624~ig B-3630 DESIGN flcation may bc designed in accordance with the design requirements ofSubsection NC.
(2) Class 1 piping may be analyzed in accordance with thc Class 2
analysis of piping systems in Subsection NC, using the allowable Class 2 stresses and stress litnits, provided the specified scrvicc loads for which Level A and B Service Limits are designated meet all of the requirements stipulated in (a) through (e) below.
(a) Atmospheric to Service Pressure Cycle'. The specified number of times (including startup and shutdown) that thc pressure will be cycled from atmospheric pressure to service pre--ure and back to atmospheric pressure during normal service Goes not exceed the number of cycles on the applicable fatigue curve of Figs. I-9.0 corresponding to an S, value of three times thc S value for the material at service temperature.
(b) s'Varmal Service Pressure Fluctuation. Thc specified fuU range of pressure fluctuations during normal se~ce does not exceed the. quantity
/a X Design Pressure X (S,/S ), where S, is the value obtained from the applicablc design fatigue curve for the total specified number of significant pressure Quctuations and S is the allowable stress intensity for the material at service 'temperature.
If the, total specified number of significant prcssure ttuctuations exceeds 10~, the S, value at N =
10g may bc used.
Significant pressure tluctuations are those for which
'the total excursion exceeds the quantity:
Design Pressure X
t/a X (S/S
), where S is the value of S, obtained from thc applicab1e design fatigue curve for 10g cycles.
(c) Temperature Dt11'erence Startup and Shutdotvn.
Thc temperature di8'erencc,
'F, bctwcen any two adjacent points'f the component during normal service does not exceed S+2Za, where S, is the value obtained from the applicablc design fatigue curves for thc specified number of startup-shutdown cycles, a is the value of the instantaneous coetTtcient of thermal expansion at the mean value of the tempera-tures at the two points as given by Table I-5.0, and E is taken from Table I-6.0 at thc mean value of the tcmperaturc at thc two points.
(d) Temperature Difference fVormal Ser-vicr.e Thc temperature dhTerencc, 'F, between any "Adjacent points are dcgncd as points which are spaced fess than thc distance 2 v')17 Crom each other, where R and r arc ihe mean radius and thickness, respectively, ol'he vessel, nozzle, ttange. or other component in which thc points are located.
~Normal service is defined as setvice, other than startup and shutdown, resulting, in specined Service l.oadings I'or which Level A Limits, Lcvcl 8 Limits, or Testing Limits are designated.
119
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r
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S 6lf 8
1/2 angle between adjacent miter axes
, S miter spacing at center line
. FIG. NB-36cj4(b)-I MITER JOINT GEOMETRY g) The hfdf-width of the reinforcement zone sM1 be limited as shown in Fig. sSB-3643.3(a)-31 Ld
'I
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g (3).Venal Available Jar Rein/orcernenr. The rein-forcement area shaH be the sum of areas A1 + Az + A3 dcQned in (a), (b), and (c) below and shown in Fig.
NB-3643.3(a)-3. %fetal counted as reinforcement shall not be applied to morc than onc opening.
(a) Area Al is the area lying withia the reinforcement zone that results from aay excess thickness available in thc wall of the branch pipe:
A, 2L(T', r,)
(b) Area Az is thc area lying within the reinforcement zone that results from excess thickness availablc in thc lip of the extruded outlet:
As ~ 2rs(T, T'a)
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(c) Area A3 is the area lyiag withinthc reinforcement zone that results from any excess thickness in the run pipe wall:
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As ~ d(T'- cr)
. NB-3644 Mlters Mitered joints may be used in piping systems under thc conct'rions stipulated in (a) through (d) below.
(a) T 1 minimum thickness of a segtnent ofa miter shall b:termined in accorchacc with NB-3641. The minim~ thickness thus determined docs not allow for the discontinuity stresses that 'exist at the junction between segments.
Thc discontinuity stresses arc reduce for a given miter as the number ofsegments is mcreased.
- 9) The angle 8 in Fig. NB-3644(b)-I shaH not bc more than 22,"z deg.
(e) Thc center linc distance S between adjacent miters shaH bc in accordance with Fig. ~i3~)-l.
(d) Stress indices and Qexibility factors shaH be determined in accordance with the requirements of Appendix II.
NB-3645 httachments (a) Lugs, brackets, stiQeners, and other attachments may be welded, bolted, or studded to the outside or
'nside of piping. Thc eQ'ect.'f attachments in produc-ing theraul
- stresses, stress concentrations, and re-straints oa prcssure retaining members shall bc taken iato account in checking for comptunce with stress criteria.
(b) Figure NBM33-I shows some ty'pical types of accc ptabl c attachment welds (NB-4430).
~646 Closures I
(a) Closures in piping systems nuy be made by use ofclosure Qttings, such as blind Qanges or threaded or welded plugs or caps, either auaufactured la accor-dance with standards listed in Table NB-3132-1 and used within the speciQed pressure-temperature rat-ings, or aude in accordance with (b) below.
(b) Closures not manufactured in accordance with thc standards listed in Table NB-3132-1 may be made 127
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,o'or more adjacent openings are so closely spaced that thc reinforcement zones overlap, the two or more "openings shall be reinforced in accordance with NC-3643.4, with a combined reinforcement that has a
strength equal to the combined strength of the reinforcement that would be required for separate openings.
No portion of'he cross section shall bc
. considered as applying to morc than one opening or be evaluated more than once in a combined area.
(h) MarJ'in@.
In addition to the above, the Cer-tificatc Hol'der shall be responsible for establishing and marking on the section containing extruded outlets, the Design'Pressure'and Temperature and the Cer-tificate Holder's name or trademark.
NC-3643.5 Branch Connections Subject to External Pressure (a) Thc reinforcement area in sq. in. required for branch connections subject to external pressure shall be 0.54 (t g (d,) (2 sin a). See NC-3643.3(c)(l).
(b) Procedures established for connections subject to internal pressure shall apply, for connections subject to external pressure.
YC-3643.6. Reinforcement of Other Designs. The adequacy of designs to which the'einforcement requirements of NC-3643 cannot be applied shall bc
>roved by burst or proof tests (NC-3649) on scale models or on full size structures, or by calculations
. previously substantiated by success{'ul service of simi-lar design, NC-3644 Mlters Mitered joints may be used in piping syst ms under the conditions stipulated in (a) through (e) below.
(a) The thickness of a segment of a miter shall be detcrznined in accordance with NC-3641.1. The re-quired thickness thus determined does not allow for the discontinuity stresses which exist at.the junction between segments.
The discontinuity stresses arc i
'reduced'for a given miter as the number of segments is increased.
These discontinuity stresses may be ne-glected for miters in noncyclic services with incom-pressible fluids at pressures of 100 psi (689 kPa) and under, and for gaseous vents to atmosphere.
Miters to be used in other services or at higher pressures shall meet the requirements of NC-3649.
(b) Thc number of full pressure or thermal cycles shall not excels 7000 during the expected lifetime of thc piping sy.
m.
(c) The a~
e 8 Fig. NC-3673.2(b)-l shall not be
- ..morc than 22,sdeg.
I (d) The center line distance between adjacent miters shall bc in accordance with Fig. NC-3673.2(b)-l.
(c) Full penetration wilds shall bc used in joining miter segments.
NC-3645
. Attachments Extern'al and internal attachments to piping shall be designed so as not to cause flattening of the pipe, excessive localized bending stresses, or harmf'ul ther-mal gradients in the pipe wall. It is important that-such attachments be designed to minimize
'stress'oncentrations in applications where the number of stress cycles", due either to pressure or thermal effect, is rehtively large f'r the expected lif'e of the equipment.
NC-3646 Clos urcs (a) Closures in piping systems shall be made by usc ofclosure fittings, such as blind fianges or threaded or welded plugs or caps either manufactured in accor-dance with standards listed in Table NC-3132-1 a~d qsed within the specified pressurc-temperature
- rating, or made in accordance with (b) below.
(b) Closures not manufactured in accordance ~i.h the standards listed in Table NC-3132-1 may be maCe in accordance with the rules contain'ed in NC-3300 of this Subsection using the equation t =,t + A, where t =minimum required thickness, in.
C=pressurc design thickness, calculated for the given closure shape and direction of loading using appropriate equations and procedure in NC-3000, in.
A=sum of mechanical allowances (NC-3613), in.
(c) Connections to closures may be made by weld-
- ing, extruding or threading.
Connections to the closure shall be in accordance with the limitations provided in:NC-3643 for branch connections. If the size of the opening is greater than onc-half the inside diameter of thc closure the opening shall be designed as a reducer in accordance with NC-3648.
(d) Other openings in closures shall bc reinforced in accordance with thc requirements of reinforcement for a branch connection.
The total cross-sectional area required for rcmforcemcnt in any plane passing
.through the center of the opening and normal to she surface of the closure shall not be less than the "
quantity ofd,t, where ds~diameter ofth'e finished opening, in.
t=pressurc design thickness for thc closure. in.
152
1
Distribution:
Document Control NRC PDR L
RC System R-I R-I'I'-
I I'I'-IV R-Y
-III
, R-I'I'I
/encl.
AD/L Rdg T. Novak S. Black D. Eisenhut R. Purple M. Williams H. Denton E.
Case PPAS J.
Youngblood A. Schwencer G. Knighton E. Adensam R. Yollmer R. Mattson S.
Hanauer H. Thompson
- Attorney, OELD E. L. Jordan, IE J.
H. Taylor, IE Regional Administrator, Regional Administrator, Regional Administrator, Regional Administrator, Regional Administrator, Sandra Clingman, R-III Herbert H. Livermore, R
Dennis L. Kelley, R-IY Bruce Burgess, R-I'II Gaston Fiorelli, R-V Paul
- Hannes, R-I William Hill, R-IV l4al dman F. Christianson John Garison, R-Y Alfred Chaffee, R-Y Sandra
- Brown, R-I'I'lizabeth Arellano, R-I George Constable, R-IV W. J. Dircks, EDO (3)
E.
Chr istenbury, OELD J. Scinto, OELD (,1)
A. Bennette, OELD (1), w
Qr s g,A~
'C-
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