ML20236S020
| ML20236S020 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 03/31/1987 |
| From: | Armstrong B, Raco R AEA O'DONNELL, INC. (FORMERLY SMC O'DONNELL, INC. |
| To: | |
| Shared Package | |
| ML20236R975 | List: |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737 NUDOCS 8711240173 | |
| Download: ML20236S020 (53) | |
Text
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'$ VALUATION'0FI ZION-STATION UNITS 1.AND 2 m -
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.FORKSLUG FLOW l CONDITION EVENT PER'NUREG-0737
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O'DONNELL & ASSOCIATES, INC. I ENGINEERING DEflGN Cf ANALYSIS SERVICES f 241 CURRY HOLLOW ROAD 7 PITTSBURGH, PENNSYLVANIA 15236 < (412) 655 1200 (412) 653-61 t o it , Tw x 7 t o-oe y.4as7 page 1 of 49 1719-400-002-00 . o ,
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L ' T 4 EVALUATION OF ZION STATION UNITS 1 AND 2
- PRESSURIZER SAFETY AND RELIEF VALVE DISCHARGE PIPING SUBSYSTEM s FOR' SLUG FLOW CONDITI0N EVENT PER NUREG-0737 TABLE OF CONTENTS Page 5
1.0 INTRODUCTION
t 1.1 -Summary . 6
'1.2 ' Background - 8 g; .
1.3 Description of the ' Zion Pressurizer 11 U! .' Discharge Piping Subsystem
,1.4. Scope of Work 12 14 2.0' ANALYSES .
2.1 Procedure 14 2.2 ' Validation 19 2.3 Structural Model 20 2.4 Piping Subsystem Evaluation 27 3.0 RESULTS AND DISCUSSION 28
~3.1 Structural Results 28
4.0 REFERENCES
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' '. ' EVALUATION ~OF ZION STATION UNITS 1 AND.2 !
' PRESSURIZER SAFETY' AND-RELIEF ' VALVE DISCHARGE PIPING SUBSYSTEM e FOR SLUG FLOW CONDITION EVENT PER NUREG-0737
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LIST'0F' TABLES l , Page ik f ,
'1' MATERIAL DATA' 34 .
2- SH0CK. ARRESTER PLASTIC STRAIN
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- 3. ELBOW PLASTIC STRAIN
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. EVALUATION OF ZION STATION UNITS 1 AND 2 PRESSURIZER SAFETY AND' RELIEF VALVE DISCHARGE PIPING SUBSYSTEM m'
~FOR~ SLUG FLOW CONDITION EVENT PER NUREG-0737 l,5 J
1.0 INTRODUCTION
Thisj report constitutes the O'Donnell & Associates, Inc. (ODAI) engineering: support for the Commonwealth Edison' Company's (CECO) response to the United States Nuclear Regulatory ' Commission (NRC) plant-specific
- submittal request for piping evaluation and is applicable to the Zion i Station, . Units 1 and 2, pressurizer safety and relief valve discharge piping subsystem (piping and' pipe supports). The evaluation addressed the worst case transient (faulted condition) for the Zion pressurized water reactor (PWR). As required by the NRC [ Reference 2], the worst case transient occurs'when all ~ three- of the safety values open simultaneously so that the
- loop- seal water from all three safety valves combines producing a slug-flow condition in the discharge piping subsystem. The documentation of the analysis methods, the modeling input, assumptions and techniques used in the
' evaluation of the discharge piping subsystem under the faulted condition for the linear elastic analysis'has been given in the Phase I report for this projectt[ Reference 1] (see Section 4.0 for list of References). The results
-of the Phase I~ analysis were in. agreement with the results of previous elastic analyses [ References 9 and 10] in that several components exceeded w the elastic allowable stress limits. Therefore, Phase II of this project was ' required to perform a nonlinear and inelastic evaluation (hereaf ter denote'd as- the nonlinear inelastic evaluation). The documentation and results for the' nonlinear inelastic evaluation of the piping subsystem which includes 'the' analysis methods, the modeling input, assumptions and techniques used in the evaluation of the piping subsystem under the faulted slug flow condition are the subject of this report.
1719-400-002-00 Page 5 of 49
1.1Ll Summary Ths' evaluation of .the discharge piping subsystem was based on a nonlinear inelastic analysis of the postulated slug flow event for the Lfaulted condition. per the requirements of Appendix F 'of the ASME BPV Code
-[ Reference 123-'and per the.allowables related to the load capacities, ;
. maximum displacements and maximum plastic strains. The techniques, x
- assumptions, modeling input, analysis methods, and specification of .;
allowables are given .in detail in Section 2.0 as . delineated by the Architect Engineerfs Project Plan [ Reference 44]. The conclusion of this evaluation is that the piping subsystem is qualified to the requirements of the event analyzed. Therefore the option
- of rerouting the horizontal header piping and insulating the safety valves and insulating all of the upstream safety valve piping as described. in Reference 10'is not'necessary. This conclusion was based on the analysis i; results and-.the comparison of the. plastic strains (Tables 2 and 3), the maximum support travel and.the elastic stress levels, with the allowable ,
' limits. The results of this evaluation also show that only one support
- (shock' arrester RCRS-1120) exceeded the plastic strain limit (see Figure 10 for location). : Upon failure of this support, it was removed from the system dynamic analysis model-and the analysis verified that the. integrity of the
. piping was maintained.
The~ evaluation procedure required the following steps.
- a. Determination of the thermal hydraulic conditions throughout the j subsystem (Phase 1).
b.- Determination of the dynamic forces (force time history) throughout the subsystem caused by the slug flow event (Phase I).
- c. Determination of the elastic stress levels in the subsystem 1
)
produced by the dynamic forces (Phase 1). ]
.d . Comparison-of the elastic stress levels with the ASME BPV Code Section III, Subsections 1B and NC Class 1 and Class 3 allowable 1
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linear elastic-stress levels exceeded the Code allowable stresses, d l 7 therefore, Phase II.'was required to' satisfactorily. evaluate the ;
- I
. subsystem.
Le.1 Determination of -the; load capacities,' maximum displacements and hf(,' ..g : plastic strains in thel subsystem by performing a nonlinear inelastic. analysis- of the subsystem... The applied forces were set'
, equal' toi100/90 times the dynamic forces of Phase I as. required by %, . the ASMEl BPV Code,"Section LIII,. Appendix F faulted conditions, in k
i order to demonstrate that'the actual. load did not exceed 90% of. thellimit. load (Phase 11).. f; Comparison 1of the nonlinear ' inelastic analysis results (stresses- &1 J ; and' strains)' with the ' allowable limits as defined in Section 2.0 below (Phase II).. In the determination of the plastic strain
', limits, the: conservatism of no strain hardening was adopted. Also the effect of the strain rates on the system properties was
- ' reviewed' and' considered 'not significant.
4 _
. Thel details ~ required -for:the steps listed above for the evaluation of the piping subsystem are given in Section 2. . At this point it is of prime T
importance?to stress the necessity of correctly completing one step before proceeding:tolthe'next step: .For this evaluation, the entire. piping 1 - ^ subsystem was modeled in order -to. obtain realistic results. This
.' -est'ablishedithe proper locations for determination of the dynamic forces.
The thermal; hydraulic model -was made c'ompatible with the structural model j f and-. accurate' dynamic forcescwere determined. The nonlinear elastic-plastic g modeling' for the piping- system realistically simulated the actual system in that. valid. boundary conditions, initial conditions, consistent convergence criteria .and accurate input data were specified.
. Also, during the ' analysis, the results were carefully reviewed.
Here it was shown that one support (shock' arrester RCRS-1120) exceeded the 1719-400-002 ,00 Page 7 of 49
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3 plastic strain limit. (see Figure 10 for -location). Upon failure of this j support, it-was removed from the system ' dynamic analysis model and the
- completed analysis verified that the integrity of the piping was maintained. . ;
4 As indicated 'above,-.the conclusion that the integrity of the piping is l maintained was basedJon a realistic simulation of the piping subsystem. As specified:in Section 2.0, no credit was taken for strain hardening and the ilimit strains were specified by conservative requirements. Also, to stay within the scope of this evaluation, it was assumed.that the anchor end of
- the support remained an anchor 'end throughout the analysis, e.g. anchor end bolts did not fail or pull out of their support structure; also it was assumed that the' support design was such that piercing of the pipe wall did
.not occur. In view of the above facts the ODAI evaluation shows that the
~ integrity lof the piping is maintained in the event of the postulated slug flow. ,
I 1.2 Background The pressurizer safety and relief valve discharge piping subsystem for PWRs provides overpressure protection for the reactor coolant system. A l
- water-loop seal is maintained upstream of each pressurizer safety vcive to prevent ~ a -steam inte'rface at the valve seat. This loop seal essentially eliminates the possibility of safety valve leakage. Although this arrangement maximizes the plant availability, should all three of the safety valves open simultaneously, the loop seal water from all three of the safety <
valves would combine and produce a slug flow condition. For this condition, the loop seal water from all three of the safety valves driven by the high system pressure upon actuation of all three of the valves can generate substantial ' thermal hydraulic forces in the discharge piping subsystem and its supports.
' Subsequent to the Three Mile Incident, the NRC issued NUREG-0737, Section II.D.1, " Performance Testing of BWR and PWR Relief and Safety l
l 1719-400-002-00 Page 8 of 49
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- Vafves," .[ Reference. 2] which requires. all operating plant licensees and "1 applic'an'tsito; conduct' testing to qualify the reactor l coolant system relief
" andisafety valves.'.under, expected operating conditions for design-basis'
, tran'sients 'and ' accidents.L 'In -addition to .the qualification of valves, the
' Lfunctionability fand.. structural inteyity of the as-built discharge piping j and supports.:must ~ also be: demonstrated on a plant-specific' basis.
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;In response' to these; requirements, a program for the per,formance l y ,1 testing of PWR 'safsty; and' relief valves was formulated by the Electric Power
'Research Institute.-(EPRI) [ References 3 and 4]. The primary objective of the?EPRI ' Test Program was ;to provide ful.1-scale test data confirming the functionability of' thel reactor: coolant. system power-operated relief valves
~
~
- andfspring-loaded safetyJ valves -for' expected operating and accident
+- w: ! conditions. Ne; secondTobjective' of the program was to obtain- sufficient
,x ll thermal' hydraulic load -dat'a .to permit confirmation of the piping analysis mo' d elsf that.may'be utilized; for the plant-unique analysis of safety and
' relief:. valve discharge piping systems.
p , A> thermal hydraulic computer code, RELAP5/MODl, [ Reference 5] was
, (valida'ted!'using1the ' data' collected during the test program, and its use for
'* plant-specific piping- assessments was confirmed [ Reference' 6]. An i ' additional computer code,'REPIPE'[ Reference 7],'was developed to convert
. thermal . hydraulic results of! pressure time histories from RELAP5/M001 into
+
c forceitime: histories, compatible with the input requirements of structural analysis codes. .The capability of utilizing RELAP5/M001 and REPIPE in the j
' performance of' plant-unique analyses was also demonstrated [ Reference 8].
/
' The ' original pressurizer safety and relief valve discharge piping subsystem was ' designed by Sargent & Lundy and reanalyzed as part of the NRC i IE Bulletin 79-14 effort by Stone and Webster [ Reference 9] prior to the new l 1
. accident conditions postulated by NUREG-0737. These conditions allow for the1 possibility of a: slug flow ' condition (as described above) to occur in l
?1719-400-002-00 Page 9 of 49 L
p g L l > t L L the' discharge. piping subsystem in the unlikely event that all three safety l t valves are actuated simultaneously. ! 1 . i'
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Stone & Webster and Sargent & Lundy [ Reference 10] performed the plant-i specific elastic' analysis of the Zion Units 1 & 2 safety and relief valve l l' t
. discharge piping subsystem for the postulated slug flow accident condition.
1
- Theyifound' that several' components of the' piping system did not meet the-
- allowable stress limits for' the . elastic analysis. Sargent-& Lundy l suggested the option of rerouting a portion of the piping and insulating the f L safety valves and all the piping upstream of the safety valves in order to
, maintain a' higher water temperature in'the three loop seals. A higher water temperature in the loop seals causes more of the water to flash to steam as
~
l $ it discharges.through the' safety valves. Therefore the thermal hydraulic forces will be reduced because less water will be in the slug flow. ) i i
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l Other conclusions reached by Sargent & Lundy include: "that the safety and relief discharge piping system is adequately designed for the relief I I [ l valve transisnts, including the' simultaneous operation of both relief valv9s. . Furthermore,'the operation of any one of the safety valves will not r result in 'an overstress condition for the discharge piping. It is only in the case where all three safety valves actuate simultaneously (which is extremely unlikely given their + 1% set pressure tolerance) that there is any possibility of a portion.of the discharge piping being overstressed. Furthermore, it is not apparent that the extent or orientation of the overstresses predicted would necessarily produce piping distortions hat would have' to be assumed as a challenge to flow through the piping. On this basis alone, the continued operation of the Zion plant is felt to be justified in the period before the modifications proposed (by Sargent & 1
'Lundy)Lfor the safety and relief valve piping system are finalized and implemented."
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. 1.3 I Description of the-Zion' Pressurizer Discharge Piping Subsystem 1The Zion 1 pressurizer-safety and relief valve piping system provides 4 , f oyerJpressure protection; for the reactor coolant system. This system is (equipped 'with three safets valves 'and_'two pvwer.-operated relief valves. The y;
(threeJdischarge lines: downstream.of f the safety valves feed into a common wheader. -L The twof discharge? lines downstream of. the relief valves join j together at a tee. Downstream of' this tee the discharge iline feeds 'into the s ,
!same header as the -three safety discharge lines. The header line then feeds
'11nto<a" relief; tank; Figure-1; depicts-an isometric. view ~of the subsystem j while' Figures 2 'and:3? presentischematic views of the system. The diameters of/thefdischarge lines .for' the relief and-safety. valves. are 3 and 6 inches,
> - respeptivelp. _ iThe header .is a.12 inch pipe -that terminates at a sparger
' lsubmerge'd in the relief tank. The relief ' tank has a volume of 1,800 f t 3
- and condiris 1,'400' .ft3 0f water 'under normal conditions.
L- ! bT 'A'sidiscussed'inlSection 1.2,.a water-loop seal is maintained upstream iof. each safety- valve. 'The ~ adequacy 'of these valves was demonstrated in the EPRIETest' Program, and they. have been highly reliable in actual Zion o'perationz The relief -valves are set to actuate at a pressure 150 psi below thes setpoint of the . safety; valves.; . Thel actuation of only one of the relief Valves w'ill by design preclude a challenge to the safety valves. In the
;many years of-reactor operation, the' extremely few transients that could have ch'allenged the. safety valves have been successfully reversed by the relief valves. The probability of the two relief valves failing to operate f
on Idemand;is conservatively estimated to be 2.0 x 10~ [ References 14 and
.15), which indicates a rare event. This low probability is borne out by the operating experience of all Westinghouse PWR plants, particularly four-loop iplants, in that there has never been an event that has led to a challenge of ithe safety; valves.
M 1719-400-002-00 Page 11 of 49 _: _ - _ _ = _
l ('S 1.4 . Scope of Work -
~
- The purpose of this project (as conducted by 0DAI) was to review the 1
' Stone 8 Webster and the Sargent & Lundy analyses in order to determine where
~
j excess conservatism was used with respect to the Zion Units 1 and 2 of Commonwealth Edison Company 'and reanalyze the discharge piping subsystem
. using 'more current and more realistic assumptions and analysis techniques.
The 0DAI work scope for the evaluation of the' pressurizer safety and relief valve discharge piping subsystem was divided into two phases. Two phases l were desirable because satisfactory completion of Phase I would have the potential of eliminating- the need for Phase II. The following tasks have beenl completed and were reported in Reference 1 as part of the Phase I activities:
~a. ' An independent detailed study-and review of the Stone & Webster and.Sargent & Lundy reports. This review focused on those areas where overconservative assumptions and/or techniques were used.
' b. The thermal hydraulic analysis was redone using the RELAPS/ MOD 1 and REPIPE computer codes. Undue conservatism in Part (a) was .
identified and removed from this re-analysis. The results of this analysis were the appropriate dynamic forces acting on the discharge piping system as a result of the slug flow event.
- c. The dynamic forces determined in Part (b) have been used as input to the ANSYS Finite Element progra.m {hicumce 11]. A linear elastic -finite element analysis of the discharge piping subsystem has been performed. Again, undue conservatism has been removed from this analysis.
- d.. .The results of Part (c) have been compared against the applicable i
section of the ASME Boiler and Pressure Vessel Code [ Reference 12]. 1719-400-002-00 Page 12 of 49
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, s e2 dha e Illof-this projectiwas required'to satisfactorily. evaluate the 3
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g:pipihg[ subsystem;because the elastic stresses calculated-in-Phase I exceeded E 3he' ASME' CAdelallowable -stres'ses. The results of Phase.II show.that
% rercutingithei headerspiping and insulation' of the' three safety -valves and:
> @ $0pipjngfupstream of.theithree safety valves is, unnecessary.' ;A nonlinear-fg Mkindkasticianalyhisi.wasithe major.- task of Phase II.- The following ~ tasks were - ur . ,: y , , .. , . . g> Lperfbrmed[in Phase II: A nonlinear and inelastic analysis of the complete pressurizer
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a., _ Isafety. and relief valve. discharge piping subsystem was performed.'
' lThis anahsis used discrete beam, piping, spring, plastic hinge,
_x hook andl gap finite elements?to. represent the piping and supports. g
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" . Detailddithree-dimensional finite. element inelastic analyses, were K:: fb.
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. made?off thele.l' bows: and a detailed three-dimensional finite element I,
elastic: analysis..wasjmade-of the fabricated branch. In order to L b Eaccountffor, plasticity in the branches, a plastic strain concentration factor was applied to the elastic results. The ki *- ymaximum' displacements obtained from Part (a) were applied to the Y '
' detailed: models of the elbows and branch in' order to obtain .the.
maximum: plastic strains for the elbows and branches.
. c.: !TheLresults of the inelastic analyses were compared with the
- m. . -
' strain limits specified in Section 2.0.
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i I 1
-2.0~ ANALYSES- i The. evaluation of the ' discharge piping subsystem requir(.d the six step l 1
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?fprocess outlined in Section 1.1. . The procedure followed is.given in detail belcw.
.2.1 :Procedurei The. procedure 'used to. perform this evaluation was based on the method 1 zuse'd in the. many' thermal . hydraulic analyses of safety/ relief valve piping. l i
systems as found in the literature .(see References 6, 10, 17, 18, 19 and 20). The steps followed are given below: n - a. The mesh for ANSYS finite element structural model of the piping system was developed. (See' Section 2.3). This was the most logical first step because the ultimate goal of the entire analysis was to verify
' that the . stress levels and the plastic strains in the piping system are j in compliance with the allowables. Therefore, the thermal hydraulic model which' provides the input to the structural model must be di compatible with the structural model. . The guidelin'es delineatad in References 7 and 21 were followed to ensure the the compatibility of the structural and thermal hydraulic model.
- b. Ji RELAP5/M001~ finite difference model of the piping system following s;
the' guidelines of References 7 and 21 was developed. RELAPS/M001 was written to investigate the thermal hydraulic response of light water reactors to a. loss-of-coolant accident (LOCA). Its original intent was not for the determination of pressure waves in piping systems. As a result it has capabilities which are not necessary for the solution of pressure surge problems, e.g. RELAP5/M001 contains internal heat generation and reactor kinetics data which are not needed in relief valve applications. RELAPS/ MOD 1 does not give reaction forces due to pressure surges. Therefore a post processor such as REPIPE is needed to accept the RELAP5/M001 thermal hydraulic output and resolve it to l 1719-400-002-00. Page 14 of 49
)
m ( t v V- forces. The application of. RELAP5/ MOD 1 to problems similar to the relief ' valve discharge line problem (the safety / relief valve discharge
- in' pressurized water reactors): has been discussed before in Reference 4 19. . Control Data Corporation (CDC) maintains'RELAP5/ MOD 1 on its
- CYBERNET system'and has' written the post processor REPIPE which
~
determines the fluid forces.
' U 'c. Using the thermal hydraulic output from RELAP5/M001 as input to REPIPE, i the force time' histories for all of the locations of interest were .
calculated. REPIPE is a post processor computer code that converts the I thermal hydraulic out'put of-RELAP5/M001 into force time histories at desired locations. The required output from RELAP5/M001 consists of the pressure, density, velocity, area and flow of the fluid volumes
~
from which REPIPE calculates the wave force and the blowdown force. These force time histories are generated between two arbitrary j junctions in the thermal hydraulic model. The common analytical
~
' approach is to perform structural evaluations with the forces acting along the. axis 'of piping elements. Therefore, the RELAP5/M001 thermai hydraulic output was converted into forces using REPIPE. The force time histories generated by REPIPE were composed of the sum of the wave and blowdown forces. Reference 7 discusses the calculations of each of these' forces. .The REPIPE output consists of the x, y and z components of the sum of these forces relative to the absolute coordinate system used in the ANSYS structural model.
- d. The- force time histories obtained from REPIPE were used as the forcing function input to the ANSYS structural model of Step (a) above in order to det' rmine the elastic stress levels for Phase I. The ANSYS computer prograit, is a large-scale, general purpose finite element computer
- l. program for the solution of several classes of engineering analyses.
Analysis capabilities include: static and dynamic; elastic and plastic; ~ small and large deflections; linear and nonlinear. The d 1 1719-400-002-00 Page 15 of 49
e- 1 g r r { t library of. finite elements includes: elastic pipe, tee, elbow, beam and shell' elements; plastic hinge, pipe, elbow, beam and shell elements; nonlinear, gap, . hook and limit force elements; spring, damper ! and mass elements. The loading on the structure may be in the form of
? forces, displacements, pressures, temperatures or response spectra.
L ANSYS is a verified and quality. assured computer program for Nuclear Safety-Related analyses. The Phase I force time histories with the !
< modification ' described below were also used in Phase II in order to determine .the maximum displacements, thus eliminating the need of repeating the RELAP5/M001 and REPIPE analyses. Because a nonlinear inelastic analysis was performed in Phase II, the applied forces were f j
' set equal to 100/90 times the REPIPE force tine histories as required by Appendix F of Reference 12 in order to demonstrate that the actual - .
- load did not exceed 90% of the limit load.
Le. In Phase I, the elastic stress levels obtained from' the ANSYS linear
. dynamic analysis of the piping subsystem were compared with the ASME Code allowable stress values. This comparison was made by the use of an ODAI developed' post processing routine. This routine was specifically designed for the post-processing of ANSYS solutions of piping : systems in, order to make the solutions more meaningful for code interpretation and evaluations. The results are presented for the faulted condition as governed by the ASME Boiler and Pressure Code, <
Section III, Subsection NB (Class I components) and Subsection ND (Class 3 components). Because the slug flow event is classified as an i occasional load, (Level D Service), NB-3656 applies for the Class 1 ; piping (i.e. piping upstream of the safety / relief valves) and ND-3655 i applies for the Class 3 piping (i.e. piping downstream of the
' safety / relief valves and the header) per Reference 12.
- f. LFor Phase II, in addition to verifying that the piping subsystem was able to withstand the peak dynamic loads produced by the slug flow 1
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I 1 l event (faulted condition) without exceeding 90 percent of the limit loads, the plastic strains were determined and compared with the strain l imi ts.' . (See Section 2.1.1 for' basis of strain limits). 1
- g. In addition to determining the plastic strain limits, the plastic stress limits (as, required for plastic hinge behavior) were determined a for all piping components in areas of high stress and/or high loads and/or high displacements. Values.of the plastic hinge limit moments
.'were calculated per Reference 12 requirements. The use of plastic 4
t hinges' in a plastic analysis is acceptable per Appendix F of the ASME BPV Code [ Reference 12]. The use of plastic hinges in a dynamic analysis such as the slug flow event is addressed in detail from an energy absorbt. ion basis on pages 132 to 143 of Reference 45, c h. In Phase' 11, the loads and/or maximum displacements and/or plastic strains for the supports as obtained from the ANSYS nonlinear dynamic ! analysis of the piping' subsystem were compared with their allowable limits. Also, by the use of an ODAI developed post processing routine which was specf fically designed for the post-processing of ANSYS solutions of piping systems, the plastic strains for the elbows and the L fabricated branches were determined as 'follows: (1) The strain response for the elbows and the fabricated branches due
- to a unit displacement was obtained from finite element analyses of detailed three-dimensional models.
(2) The maximum- displacements (both transnational and rotational) for the elbows and fabricated branches as obtained from the ANSYS , nonlinear dynamic analysis of the piping subsystem were multiplied times the unit response value via the post processing routine in order to determine the plastic strains. The maximum plastic ! strains were then compared with the allowable limits. Also the i l
'1719-400-002-00 Page 17 of 49
maximumsthessesforthepipingelementswerecomparedwiththe m aliowable limits.
- 2.1.1 Development of ' Plastic Strain Limits As shown :in Table 1, the piping is fabricated from the following types of stainless steel: TP304, TP316, 316 and WP316. In order to conservatively. specify high local strain values, all of the piping material
- was taken to.be elastic perfectly plastic with no strain hardening. In the real system, strain hardening significantly reduces the concentration of ;
' strains.in plastic regions of the piping system. l The stainless steel- piping material has a very high ductility.
LFracture strains are the order of 100%. The limited ductility exhibited under long term, low strain rate creep conditions at elevated temperatures is not a problem at the maximum operating temperature of 668*? and for the strain rate. dynamic conditions of interest. Low ductility under creep L. . conditions is theLresult of creep strains concentrating in'the grain j boundaries, forming voids which then coalesce to form cracks. lne ductility is an order of magnitude higher under the temperature and loading conditions of' interest for.this analysis. Thus,'there are no strain limits in the ASME Code criteria'for operating temperatures below the creep regime. Staying below 90% of the limit load is considered to provide adequate safety against cracking for faulted conditions of loading. Strains of 5 to 10% are permitted during the fabrication of nuclear { i components. Nominal strains of 2% occur during welding under constrained conditions of high biaxiality. Nominal strains of 2% also occur during
. thermal or mechanical stress relieving of weldments. Data on the effects of cold working on sensitizing the ma.terial due to stress corrosion attack indicates that large' strains (in excess of 20%) do significantly increase I the susceptibility of the material to corrosion attack. However, strains up l l
j 1
.1719-400-002-00 Page 18 of 49 l
gn - - - - - - - - -- .- -- -- - - - - - - .- rq
.\,<~'
,~ , , ,
t i ri , a T ,f- ' ito 5%3do not;sbnsitize the material; Of course, stress corrosion is a long-termLprocess and ~ s'hould not be a consideration following a. faulted condition
. event. < Because c the[ piping system operates below 800*F creep. effects and nn 7 attendant: strain concentration ~ at material grain boundaries need not be
- " l considered. - Fatigue 1 failure can also be ignored. since the slug" flow
'conditionfis:aiingle.[cccurrence faulted event. Therefore, the strain 111rhithwere takenf as conservative fractions of the minimum expected uniform w^, '
.Lelongation strain. fors the. 304 'and 316 stainless steel piping materials. The ,.
jg [ uniform . strain iithe point'at which necking of a tensile specimen begins as l LV ;shown'in! Figure ~1 of Reference _46.; At' 800*F' the . unif orm strains. for 304 and
- 316 -. stainless' steel pije and' tube; products ~ are 20.9 and 21.9 percent respective 1y'[ Reference ~433. The uniform strains increase with decreasing
> stemperatur.e. '
m m iThe strain l11'mitstimposed:in.this analysis are: . pA W l i Membrane. strain' limit: 2%
- Membrane plus bending strain limit: 4%
.
- Peak strain limit: 10%
+
Y The'2;to 1 ratio of membrane' and membrane plus bending' strain limits is
, cin 'k'eeping withl the ' strain limit philosophy of Code Case N-47 of the AME B&PV . Code, Section III, Division 1. lThe'10% peak strain limit is"less than
'halIof-theLminimum expected uniform elongation strain.
~
;c ,
i-
- 2.2 ' Valid'ation The validation of the thermal hydraulic codes (RELAP5/M001 and REPIPE)
, n . . .
[ has .been ' stated in Section 1.2 and 2.1 and is documented in Reference 32 and j IReference '38. The validation of the structural code (ANSYS) has been stated . l
' ' y $1n'Section 2.1.: The-00AI post-processing routines were verified via J' ' comparisons with hand calculations. As shown by Reference 36, only the portionjof the discharge piping subsystem upstream of. the safety and relief l i
( l g t ,i 1719-400-002-00' Page 19 of 49
- - - - ----.__________m__,__,__,,
,.... =m- --
y py . (..., t c ) ? = (,,, if , ;n L~
- g. valvesjislasafety-related-' system;however,all'of'theanalysiseffort
- 4 : ass' o ciate' d with this project -is .in ;accordance'with the requirements of L10CFR50,JAppendix B. . . In addition, the requirements of the. 0DA1 Quality
..., " "kss'urance Manual [Raference-223 and applicable portions of the Commonwealth
- Edison' Company Supplement have also been followed.
+:
;2.3 . Structural Model
, 'The pipingisubsystem was modeled from the pressurizer nozzle i '
' connections to the relief tank nozzle. This model of. the entire safety and
~
t rel.ief; valve piping system was used'in the structural analyses to account oforLinteraction between! the 'various portions of the system. The piping w" $ isometric isi given in F1gure :4. Figure 7 shows in-detail the three major. C' ;portionh;of Lthe system: the ; safety valve piping, 'the relief. valve piping,
'and" the ' common header, which terminates at .the relief tank. The' structural.
Lmodel of the safety valve tis given in. Figure 5. ' Figure 7 indicates the node 7 11,ocationsi for the structural l model for the nonlinear inelastic enalysis. EEacti safety valve branch typically consists .of 6 inch Schedule 160
?i~ n sulated stainless steel piping, including a.180* short-radius return bend
~~'
that : forms the, loop seal upstream of each safety valve. The modeling used
;3g 'forithef safety lvalveiis explained below. .Each safety-valve is supported by y a pipe stanchion connected to#e : loop seal -immediately below the. safety.
valve inlet nozzle. (See Section 2.3.1 for the stanchion modeling details.) ~
-The piping downstream of'the safety valves to the header is uninsulated 6 j inch Schedule 40 stainle'ss steel. The piping upstream of the relief valves is. insulated-3 inch and 6l inch Schedule 160 stainless steel. The relief and blockivalve' structural models are constructed in a manner similar to that of a the: safety valves discussed in Section 2.3.1. The piping downstream of the
< a
, . relief valves is uninsulated 3 inch and 6 inch Schedule 40 stainless steel. l
.The: piping l downstream of the relief and safety valves connects to a common l l
' header thatlis routed vertically downward to the relief tank. The header j
. piping is uninsulated 12-inch Schedule 40 stainless steel. In the model,
~
u 1719'-400-002-00g Page 20 of 49 h __ _ ' )
?p:n
.g .g w . .
q
,e ,ibh '"
i!( , m f3 i A'/ T ..., , j 1 s hl i jj W d 'K, s o ,,
- u. m
[thelheader.was'.considere'd anchored at the relief tank . nozzle. Pipe data
- s . , ; - .
> d relevantstof.the? structural modeling,: including. thel material identification,
, ~ w .+ .
E % iweregspecifiedLby ReferencesL24.'and 25 and are summarized in Table 1. Table
, - . , 1.. n-. .
93' J r lial'solgives the ' allowable stresses as specified by . Reference.12. W ,4 l (.
'"> > ,, t 1 Since:ZionLislanLoperating plant, the as-built piping and pipe support
+ .
}{, Thonf'i$u, rations were usedfto modelf the system [ References 26, 27, 28 and-29].
h' ihe! Stone [& Webster' support modification drawings J79-14. [ Reference ' 293 take : jysprecedencelovera the .Sargent &:Lundy Reactor Coolant' System Support ' drawings '
,j[ReferenceL283andLtheKellogg' drawings [ Reference 263takeprecedenceover L' X the[Sargentt & Lundy : drawing'- [ Reference 27]. Individual pipe support (pp $' q, ydrawings.were i
;used.to determine the11ocation and orientation of the
.j b ,!.restraintL,iAlso'the Field Walk-Down Package.given in Reference 9 was used f whenkappropriate. : Since thelpressurizer-~and relief tank diameters are more-B ,
'ithanfthree times thbLdiameter of the piping, connections at the pressurizer
. nozzles and relief ' tank were considered to be anchors in the model.
4 y jg - 213[1liModeling - De' tails' ; @[ 4 LForLthe.: nonlinear -inelastic structural analysis of Phase II, the c h i ; straight pipe sections. were modeled as elastic pipe elements, the pipe tees j M'% (were modeled as : elastic. pipeltee elements, the pipe elbows were modeled as q elasticipipe(elbow elements ~ and. the valves and . pipe supports were modeled as ' exp1'ained:bblow.1 Valuesiof the stress intensification factor were used for Lm Tall) piping; components.as specified by Reference'41. In order to' allow for
'. 'pjasticide_ formation,-' ANSYS plastic hinge elements and/or ANSYS limit load !
Jelementst and/or ANSYS displacement control elements were used in areas of l highlstress and/or high loads and/or high displacement. Values for the - I r ; %; , . plastic; hinge moments were . calculated per Reference 12 requirements. Values q h [for. the 11mit' load' and displacement control elements for the various pipe ; a supports are discussed below. In order to simulate the nonlinearity of the J system,LANSYS ~ nonlinear gap, hook, 'etc. elements were used as explained lelow. For al1 items of,the piping subsystem, the standard structural
~
l l' Page 21 of 49
~
(1719-400-002-00
a y-modeling practices were followed in developing the ANSYS structural model of the discharge piping system. .These include, but are not limited to, the
.following:
'Ia.. Pipe Supporcs
<In addition to the' safety valve stanchions, the piping subsystem employed .the following types of pipe supports: rigid / sway type pipe supports, flailing supports,' shock arrester supports and constant force L ' supports. The. models .for these various types of supports are explained
-below. -Contrasted to the Phase I pipe support model consisting of a pipe node connected via a. spring element to the anchor node which was constrained in all directions, the Phase 11 pipe support modeling included nonlinear elements as expl'ained below. The mass of the support. clamps and the mass of the dynamic portion of the support attached to the pipe were modeled as a lumped mass and placed on the pipe node. at or very near to its physical location. The values for the masses were obtained froni References 28 and 29. A node at its physical location. corresponding to the centerline of the pipe was used to represent the end of the support attached to the pipe. A node at its physical location was used to represent the anchor end of the support.
.The constraint of the anchor node was consistent with the actual
. physical configuration. Also, to stay within the scope of this evaluation, it was assumed that the anchor end of the support r mained
. an anchor end throughout the analysis, e.g. anchor end bolts did not fail or pull out of their support structure. Any freedom of motion of the anchor point associated with any significant gaps was accounted for in the model.
For the rigid / sway type pipe support, an ANSYS spring element was used to connect the two nodes uf the support. Also the load capacity was calculated per Reference 12, in order to verify that the limit load was not exceeded, i.e., that the support did not fail. 1719-400-002-00 Page 22 of 49
[' i For _the flailing type pipe support, an intermediate node was added so that' the support was modeled as an ANSYS spring element in series with the ANSYS' nonlinear gap / hook element in order to account for any
, unrestrained _ motion. Also the load capacity was calculated per 5 Reference 12 'in order to verify that the limit load was not ev.eeded, li.e. , that the' support did not fail.
' For the shock arrester type pipe support, two intermediate nodes were added so that. the support was modeled as an ANSYS control element in series with an ANSYS spr_1.1g element in series with the ANSYS nonlinear gap / hook / damper element and the ANSYS limit load element. The control Lelement was used in order to provide the capability to simulating the 4
- . shock arrester breaking should its displacement exceed 2% plastic
- strain, The gap / hook / damper element was used in order to account for
'any unrestrained motion and the " lock-up" of the shock arrester under the ' dynamic condition. The limit load element was used to simulate
. plastic strain in the shock arrester once _the shock arrester exceeded its _ load limit. The values of the spring constant were obtained from References 9 and 30. The values of the limit loads were obtained from the shock arrester manufacturers' catalogs [ References 39 and 40) in order to determine if the , limit load was exceeded, i.e., if any support failed.
- The constant and variable force type support was modeled as a lumped mass to represent the weight of the pipe clamp and the dynamic portion of the support. The values of the forces and the masses were obtained from. References 28 and 29. The masses and forces were placed on the pipe nodes at or very near to their physical locations. Also the displacement capacities were obtained from the manufacturers' catalogs
[ References 40 and 41] in order to verify that the limit displacement was not exceeded, i.e., that the support did not fail. 1719-40.0-002-00 Page 23 of 49
2 b.- Pressurizer and Relief Tank Connections T6e locations' of the pressurizer and relief tank connections were
' represented .by pipe nodes ~ at their physical locations corresponding to
'.the centerline of the pipe. The pipe nodes were connected to coincident nodes via an ANSYS plastic hinge element in order to allow for plastic deformation. The coincident ncdes were constrained in all degrees of freedom. This was a conservative approach because no credit F 'was taken for the local flexibility of the anchor point.
, , - c. Valves All of the valves were modeled using three relatively stiff beam elements and a mass element at the valve center of gravity as follows:
'1 one beam element running from the node at the valve inlet to the node
(" at' the valve outlet, one beam element running from the node at the valve inlet to the node at the valve center of gravity and one team element running from the noce 'at the valve outlet to the node at the velve center of gravity as shown in Figure 5. The values for the j ,. p locations of the nodes at the center of gravities, inlets and outlets and the values for the masses were obtained from References a and 30.
.d. Safety _ Valve Stanchions The safety valve stanchion was modeled as a two node beam element. One node was attached to the center line of safety valve inlet piping corresponding to its physical location. The other node was at the anchor end of the stanchion at its physical location. An ANSYS plastic hinge element was used between the node at the anchor end and a % coincident node in order to allow for plastic deformation. The anchor node was constrained in all degrees of freedom. Data for the safety valve stanchions were obtained from References 10 and 29.
1719-400-002-00 Page 24 of 49
4 i
- e. ' Detailed Models'for the Elbows and Fabricated Branches In addition to using ANSYS plastic and nonlinear elements, detailed three-dimensional finite element inelastic analyses were made for the fifteen different. elbow geometries and a detailed three-dimensional
- finite element elastic analysis was made .for the 45* fabricated' branch r geometry (see Figure 6). For each of these models, the strain response due' to a unit input displacement.was determined via ANSYS static
~
analyses. The maximum plastic strain for the elbows and fabricatea branches was then determined by multiplying their maximum displacements
.(as obtained from the nonlinear transient dynamic analysis) times the strain response due to a unit displacement. In order to account for plasticity in the' branches, a plastic strain concentration factor was l
applied' to the results of its elastic analysis.
- f. Thermal Hydraulic Forces The applied forces were set equal to 100/90 times the dynamic forces of Phase I as explained in Section 2.1.d. In the nonlinear inelastic h analysis, these forces were applied directly to the nodal locations in order to give an accurate force time history representation of slug flow event. As. mentioned above the guidelines given in Reference 7 and 21 were' followed in developing the structural model so that the ANSYS model nodes included the locations of high stress levels. As mentioned above, REPIPE calculated the wave and blowdown forces for the desired locations and then the force time history was applied to the ANSYS structural model in order to determine the stress levels of the discharge piping system.
A sketch of the structural model showing the node locations is given in Figure 7. 1719-400-002-00 Page 25 of 49
m - - - - - - - - - - - - - - -
; p; " ~* '
ggg m m @4a %. D:;; a -
, i % $ 5kl. 5 h Q '
# xI' -
Q$gg' D.4 ,g- ' iS(N) W% % ! . , y e ,, V% ' - ' >
- 'gy
,y f, M[F Structural 12.3 lf .;.
J Analyses.: w" p' # ?,a .-
- JStaticj(deadweight)) plusj thermal expansion,i modal' and ' dynamic. analyses-m b,
- p" ' , ' ?oSthM n "
;A nonlinearJineldstic model were; performed usingi ANSYS as given .;
Lbelow. ' %@gr ?J -1. - - .. . . - .... ' 1 1 $ig a g 5Thesstatic analysis 1forfthe#.. dead ' weightiload- was: performed' using . the ' f hp J STATICir' o utinelof ANSYSh @ f 'jSij R The"modalianalysisiforLth'e-pipingisubsystems was; performed.using'the p Ql g i;M0dAL-l routine'of'ANSYS.- gdNy (cy hhe; dynamic analys'is. for the: piping > subsystem was performed;using the~ c ' a ^ %i inonlinearitransiedt dynamic f routine 6f.' ANSYS. . The ' dynamic . analysis; y w ($' < J3w Mi ~ Musedfthe thermal? hydraulic transient loads due to the -safety valve'- w ^ xv ' "-" factuation. [In order .to'. adequately resolvef the? input and output iN'
;, .. response (o'ff ths : system, ean integration time stepLof'0.0005 second was-1' .
*. 'used. LThe a'dequacy.loff this time step has'also been demonstrated .by the -
'm f,' '
4ensitidty studies Lof Re'ference 30. . ' A dampingvalue of 2%.as INW, hspecified.[in LReference' 33 was used. 3, . m llsin lb N w\ ' ,. . . . . , .,, LThelresultsiofsthe(static.and' modal analyses for the' inelastic model h $ hagreed. with L th.ose of: thelelasticTmodel. (Note that'ANSYS neglects nonlinear -- w W , Telementsi foMa l modal 7 analysis. ) The results"of the nonlinear transient
, m --. . ~ ..
,,'4
' dynamic analysisiaref discussed in Section;3.1.1.
,4
~ p);' .
Y's d23.31PlintOperating--Condition's L j fourLtypes ofi plantioperating' conditions may exist. This evaluation
<> considered only; the< faulted conditions. Faulted conditions are defined as Ethbseicombinations of' conditions associated with extremely low probability, 4 / (i.e[,jpostulatedLevents whose consequences are such that the integrity and gf , Toperabilityc of' the nuclear energy system may be impaired to the extent that M lpublic health and- safety l considerations are involved. The safety valve
+ ., vtmsient/ loads:and Ithe relief valve transient loads are classified as
;faulte'dLcondition loads. l l,
t 1 o
, 1719-400-002-00 Page 26 of 49 w ,
Crc4- < L a j
mm d 3 15 1 ( 4~ q iX; , '
,'/,
i 47 . g3 c
, ;s,.
th x z. . l W kh' "
- 3' < *
, f me e4
~
yg f , . , i p.Hg .ggad'Condiftons-For.Ithelfaulted condition causediby. the slug ' flow, the evaluation of r f
,the" subsystem included the. weight and lhd ih t eht erma ; y raulic conditions-
- (i.e.,?temperat'ure, pressure andl slug flow. forces). . Based on the results of 1 Y" l [theJ; pressure -transients obthinedLfrom the-thermal' hydraulic, analysis-(see Reference!1),cthe peakipressures used in the. faulted, condition stress :t
- e calc 0lbionwere': 2,750Ipsia~'forJthe L piping upstream of the val'ves and .700 l
, , . .s ~. .. , ,
g l psiatfor? the' piping" downstream of; the' valves. . The specified' temperatures as - N, given:in Table 1 were" used inithe' evaluation. The ' safety andl relief valve [dischargenlines:were evaluated'for; thrust' loadings caused by the slug flow .[
;lrs s .
-m s -.
l
" :;resulting L froml thels. simultaneous' actuation of the safety valves.?
g- - w,
+
-:4 ,
l c ~ C.,2. a 4 UPipingSubsy'stemEvaluation- . T7 [The evaluation? of thel discharge piping 'sutisystem . consisted of the six
'.'step, procedure; 0utlinddlin Section 1.1 sith the " bottom line" being the
.y Jcompaki.sonJof :the. results of the' analyses with the' Code allowable limits. h3 7 The information' relevant to the Code allowable limits is given below. ! j
, ' ;E M 12.4[1I ' Inelastic' Analysis d f i 'A}nonlinearlinelastic analysis (with the dynamic forces increased by 1 i 9the factor?100/90 as explainedlin .Section 2.1.d)- of. the piping between the f pressurizer.inozzlesland1the. pressurizer relief tank was performed.to satisfy
~
~
[, 'the; requirements 'specifiedlin Section.1.1.1 for the ' faulted conditions as ;
* : produc'ed by. the postul'ated slug flow. Per Reference 12, this type of event l Mis" classified as an. occasional load '(Level D Service). For the materials j
.under- consideration for the inelastic analysis (Phase II), the definitions l and = the" values l of.' the allowable stress A(S ) as a function of temperature per f
+ '
LReference'12 are given in Table 1.
~
f g m 1 n ' 3.. J l 1 I 3 v1719-400-002-00 Page 27 of 49 l s x ( $
yy , ~. ;. ; .g .- y- - ___ - hk ~ Lh'de b Q@ c MQ"M L s x'-' V: . x na <* gy *
~ ,
, , g.
Q ."8- , p [e ' Q .
~
kl * ' .l. .; r . . ' .b s , M j (3.0j RESULTS?AND7 DISCUSSIONS ( k, my ,iThe] evaluation'offthe!pipingLdischarge' subsystem first required thermal .
')
w - . 1
~
I , %jydfaulicianalyses toid'eterrhine thenthermal' hydraulic-' conditions throughout:~
, ythej entire j subsystem.; .Next',l. structural f analyses ' were . perf ormed -to . determine - 1
, 4 w ....%. ..g.. < , . , s. . ,. < . . . .
).
e@ . 9 Lthe i stress .
.x 11evel x s L and,maximumi strai ns ; throughout : the enti re L.sub system.
d 1, MLastlyitheistressRlevel's"and!maximumistrains for each component of then s y5tsm[we're compaEed g withitheL a110wab1'el11mits . The: results of these K analysesfandithe! compari. son withithe> allowable. limits are given below. . .; r _- op, # , [.? ,' x .lll . . .. . . . , N R3:19 STRUCTURAL;RESULTS! N !I . " w ' j. - . . . , .[... ,, Es i e LForf Phase'. Ilhthe,results: forfthe REPIPE thermal . hydraulic forces were . '
' ,[:: multiplied bh(the .
i faitor)100/90 as .ex'plained;in Section- 2.1.d. Plots of l 6 lthese$ther, mal +
/ hydraulic $ forces l acting Lon the horizontal ' header are shown =in. '
j & ,l. Figure's 81andi9h dhe'seres01kare typical ~ for ihe analysis of the tsafety Y as - .. m m , .. . s. . . . , b my
, Sal.ve andl header: piping subsystem. These'. figures show that the thermal ;
. ,7 .
j
+ hydraulic { forces can be quite.large but' act over a short time period as
. ,( ggoverned .by/thefslughflow and;areDin agreement with other slug flow analyses y
' N j $ (References 76h.8; J10/17El8,19, 20, 30 'and 37]. ]
m, i
> r i
iThe as-built configur'ationifor the-piping discharge subsystem as shown
',- (10 FiguresL4 tto 7 was?modeledrusing the ANSYS computer code.as described in ,'~ , LSection'2.3'.1Jfor! the nonlinear inelastic model.1 The. load' conditions given >
LinLSectioni2d.4here 'usEd tol determine the stress levels and. the piping
~
, 4 isystem response 1as governed'by the Code requirements given in Section 2.4. i
-.3;2.lo NonlinearoInelasticf Results (Phase II)
IThSiresulis~(se~e Tables 2 and 3) from the nonlinear' inelastic analysis
~
Hncludeithelforces1 acting: on 4 all: of the pipe supports, the maximum 1
' ~
Displacements?ofL alliof 'the' components, the plastic strains of the j R o components [that E exceeded:the elastic limits and the elastic stresses of the ; piping ' elements [that did not exceed the elastic limits. Examination of the
~m. .-
4
- 1resultsfshow that'three safety . valve stanchions did not fail because they
^
.1719-400-002-00 Page 28 of 49 ds ' '
N./ '1 -
,..._L.._:-__-_._ _ _ _ _ __
- ' - - ~ ~ ~
[ %f' m >s l tj ' y g[ l
}z , ,7
$ .,u
. ('
g A y ys ' _.yp; q[= ? f :
,S ;. , ,
1
, o . , . . ..
-- < 'f ' .
W gdidgnot ~golpl' astic. Examination of the results show' that none of the
. m" , n. . . . - - .
- sway /rigidTand ~none Lof Lthe flailing pipeLsupports exceeded their load limit l;}. [ , sforce, but 50% of' the' shock arresters ,(9 out of 18 total) did ' exceed their.
@,,4 ,el'oadilimit[eFor'8:out"of-the.9:
.n ..
.. 1 shock arresters that exceeded ^their load f Wlimit,(Table 2ishowsithat. theimaximum strain is less than 1% which is within . .
m - - p ^J eveni the ' membrane ' strain ;11miteof .2% . allowable'.as specifled. in' Section' f,, c2.2.1., .Therefore,;except for shock: arrester RCRS-1120 all'of the n '
% istanchiofts,fpipecsupports and shock arresters are qualified. .(See Figure 10 ~
~
', , _ forL. location ~of shock arrester- RCRS-1120. )' Table:3 lists the 7.' elbows (out 4 i w < , ' L offs LtotalLof'49)' for1which thel elastic : limit was exceeded. ' As shown by e ' LTable 3, .theLmaximum ' strain isEless than'1% for. all of~ these elbows. m m y A Therefore,:all dfithel elbows are qualified.. For all three'of the fabricated 5#C irandhes.the elastic! limit has' exceeded. - However the. maximum strain was
. . .. s .
61ess than 2%4 forf all 3 of the ' fabricated branches, even after the plastic - i, l strain concentration factor was applied. Therefore, all 3 of the fabricated s [ branches..'are qualified. Examination of thel maximum . displacements for the r fconstant' and variable force supports show;that the limit displacement is~ not
, . exceeded' for anyL of the constant .or variable force supports. Therefore all q; ,
3ofL the ' constant' alidav' riable' force supports are qualified. Because the-4 , l
+ f elastic limit.i f :all .'of the remaining components was ' never exceeded, at this
.' point:it may be asserted:that the- entire pressurizer safety and relief valve Ld ischarge' piping subsystem.is qualified.to a maximum plastic strain of 2%
-except for; shock: arrester RCRS-1120. As previously explained, this shock
~
arrester was removed from the . system dynamic analysis model upon failure and the. analysis: verified that the integrity of the piping system was maintained. Should the slug flow event occur, this shock arrester should be
~
thoroughly 1 examined ~ to verify the need for replacement. t
- . j 1
L !1719-400-002-00 Page 29 of 49 Ch _
gqy ,y, x wpi t + A
- b. - ,t ll( O
- 3; LlB
..y 4
+ 6 >> - ' f'
! 4.01 REFERENCES e' F1. . 0lDonnells & Associates,. In'c;, " Evaluation:.of the Pressurizer Safety- and
.n: ', Relief Valve. Discharge Piping Subsystem, Zion Station' Units 1 and. 2, iPhase11L- Elastic Analysis,: 0DAI Report 1719-400-001-00, February o sp :t19.86.
.M .342.;;Unitcd States Nuclear. RegulatorL Commission, " Clarification' of the TMI s 1 ,
. Action: Plan Requirements," NUREG-0737, Item II D.1, NRC Docket Humbers
,50-295 and. 50-304L November 1980.'-
- w. c, ,.
~~
13k Electric 'PowerLRe' search Institute,:"EFRI PWR Safety and Relief. Valve Test Program;lSafetyJand Relief Valve Test Report," EPRI NP-2628-LD, sEPRIl Project,V102n Interim _ Report,. September 1982. Ay L42,l Electric Power'Research[ Institute, "EPRI/CE PWR Safety Valve Test m , 37 : Rsport," Volumes >1-10,.; EPRIt Rroject V102-2, Interim Report,1983. s og th' 'H 5. l k'ansom,L V. H.' ' et 'a1. ,s "RELAPS/ MOD 1. Code Manual'," Volumes 1-2, NUREG/CR-
- 1826;' EGG-2070,, March 1982.7 m
v 6 ( 161 "Oouse,lR.[K[et 'a1.,:" Application l of RELAP5/ MOD 1 for Calculation of ~ Safetyrand ReTTeT Valve Discharge Piping Hydrodynamic Loads;,," EPRI h[ L , ;
-NP.-24796 EPRILProject V102-28, Final. Report, December 1982.
17.; ;. Norton,, P. ~J. ,"" User's Manual . for ' Program REPIPE," Publication 8.4001760, Revision C, Utilities Service Center', COC,'Rockville, s Maryland,(August 31, 1983. 18; Electric Power Nesearch Institute, " Dynamic Loading on Pressurizer
. Safety.and Relief Valve Discharge Line Due.to Valve Actuation," EPRI
< Project 'VI-2-45, Final' Report, submitted .for publication in January
.1983.'
w9. Books l' through 6 inclusive, of Stone & Webster, " Zion Station Pipe Stress.and; Support Analysis Report," Humber 13430RC - 2, 3, 4, 5, Revision Of dated January 17, 1983, Commonwealth Edison Job Order 113430.01'for Reactor Coolant (Pressurizer 1RC002 to Pressurizer Relief
' Tank .1RC003) .
'10.. Sargent:& Lundy Report SL.4283' dated May 2,.1984, " Evaluation of the 3
Pressurizer Safety and Relief Valve Discharge Piping System - Zion 4 Stations 1 and~2. 1 ll. .;ANSYS Engineering Analysis System, Revision 4.10, Swanson Analysis
. Systems :Inc., . Houston, Pennsylvania.
i Page 30 of 49
,g :1719-400-002-00 l.m.._m.__..um 3 ._
,,X < 4 <
%Pyg aQ '
\ ) . / 1 .'
y;4 , m ;c th: ] m ue,
!' ! e
+ ,
, m -
[
/
i
,' lm.% , .. . . _ i . . A. . ,
mm % f L1~ 'Sub,sectiongND,41983 k fASME4 Boiler and* . throughPres'sure Vessel Code,fSectioniIII, Subsection N Winter of:1985. .
' %" > < : L13.'llNRCiletterLdated February -19,;1985, Docket No. 50-295 and.50-304 to Mr.
L I ,_ y j 0. L KFarrar,fCECo;from Mr. S. A. Varga, NRC Licensing Division. . f; ~ a6 L14.[ Westing' house Nuclear Energy 1 Systems,: " Review of Pressurizer Safety ! g -ValveiPerformance asl0bserved in the.EPRI Safety and Relief Yalve Test j Ki g gg d Program," . WCAP-10105, l June 1982. c g '7
, l j;15,,i" Electric'PowerRes'earchInstitute,'"ValveInletFluidConditions'for ff' PressurizeriSafety'and Relief Valves:in Westinghouse-Designed
, s ' W , l Plants,"EPRIl NP.-2296',j EPRI Project, V102-19, Final Report, December ! NX
- L1982.D r gg- -
W 16), Science"L Applicationsdnc.. "Probabilistic' Evaluation of High Pressure ! m ,
.. ;Lig'uid Challenges to . Safety / Relief Valves in- the Zion, Byron /Braidwood
^ M ; PWR Plants,"LJune;25,J1982.
, y.
il7. Motl'och,?C. G.,' Van B1aricum, C. H.,Iand Naraum, R. E.,
"RELAPS/ANSYR/ANSYS Hydrodynamic. Force Calculation of the Electric
~
' Power Research Institute' Safety and Relief Valve Discharge Test'(CE Test No. 1027) 7 El-83-12,. December 1983. u
,m lN , y
+ :18. ': Cajigas[JfMs,"Verificationof.'theRELAP5-FORCEHydraulicForce -!
- CalculationTCode,", Gilbert ' Associates, Inc. , May 1984.
, : /19. iSemprucci; L.1' and Holbrooi, B.' P... ."The ' Application of RELAP4/REPIPE
, w '
to determine Force TimelHistories on Relief. Valve Discharge Piping,"
+
,, ASME, PVP-33,SJune 1977.:
- : 20.; Strong,B.R'.,[Jr.landLBaschiere',iR.;J.,"SteamHammerDesignLoadsfor
' 1 Safety / Relief Valve' Discharge Piping," ASME, PVP-33,, June 1977.
R W, 21'. - Criteria and Guidelines; for the' Design of Safety and Relief Valve M : Installation in Westinghouse Pressurized: Water Reactor Plants," a Westinghouse: Electric Corporation, NES, PWR Systems Division, October l dj :1972. , ; 122. l0'Donnell & A'ssociates, Inc., Quality Assurance Manual, Revision 5, 4 w -dated: January 15, 1985. i v, .
! 23. LGraesser; K. L. , (Zion Station Superintendent) to Butterfield, L. D. ,
(CECO), Letter November 9,'1982, " Unit 2 Pressurizer Safety Valve Loop Seal' Temperatures. " y ^
,7 ,
1719-400-002-00 Page 31 of 49
, t r
y.
?
'24. ." Zion Piping Design Table 'E' Stainless Steel," five pages dated
(("
' February 15, 1969, revised December 30, 1970, numbered X-2242 and X- 1 2245.
25, " Zion Piping Design Table 'L' Stainless Steel," six pages dated February 15, 1969, revised December 30, 1970, numbered X-2242 and X- i
'2245.
..W
'26. Kellogg Company Power Piping Division, Job No. N8342, System #34 Reactor Coolant, Drawings:
150 1-34-15 Rev. 2 150 1-34-22 Rev. 1 150 '1-34-20' Rev. - 150 1-34-23 Rev. 3 150 1-34-21 Rev. 1 150 1-34-24 Rev. 1 l
- 27. Sargent & Lundy Drawing M-418, Pressurizer Piping Analytical Data
. Isometric, Zion Station Unit 1, Sheet No. 1, Rev. O, dated July 31, 1979.
- 28. Sargent & Lundy Reactor Coolant System Support Drawings:
f Hanger No. Date Hanger,No. Date IRC146-FRI 8-25-77 RCH-1008 12-18-72
-1RC146-SR1 4-21-77 RCH-1009 1-28-74
-1RC147-SR1 4-21-77 RCH-1014 10-27-72 c
L 1RC147-SR2 4-21-77 RCRS-1112 11-20-72 1RC151-RV1 4-21-77 RCRS-1114 6-02-71 IRC157-RV1' 8-25-77 RCRS-1115 11-20-72 1RC157-RV2 4-21 RCH-1007 1-12-73 RCH-1005- 10-27-72 RCRV-001 12-21-72
- 29. Stone & Webster Bulletin 79-14 Modification Support Drawings: ;
i Hanger No. Date Hanger No. Date J RCH-1006 2-10-81 RCRS-1123 2-04-81 1 RCH-1010 1-30-81 RCRS-1117A 7-22-81 1-30-81 RCRS-11178 7-22-81 l RCRS-1117 RCRS-1118- 1-30-81 RCRS-1118A 7-22-81 RCRS-1120 2-04-81 RCS-1011 11-18-82 RCRS-1121 1-30-81 RCS-1012 11-18-82 RCRS-1122 1-30-81 RCS-1013 11-18-82 RCRS-1123A 8-10-83 RCRS-1119 11-10-82 , 1
- 30. Sargent & Lundy Report No. 037064, Project No. 6320-00. " Dynamic Analysis 'of Typical Pressurizer Safety and Relief Valve Discharge l Piping Due.to Valve Actuation," dated August 1982. l l
1719-400-002-00 Page 32 of 49 , i mu .
,m; x -
e v %:: kl. , (( .hkb.. - , k ", J v._ , o~ ' /M, g yg - 14 ' [31h1 Private communication, Dr.t Choi,- Combustion Engineering, Inc., W indsor, [ ,.
, M Connecticut, LJanuary .7,;1986.
, @m S $32.;! Patrick,; B.t H. ' (CDC CYBERNET Quality Assurance Manager) to- Raco, . R. J.
," { 00AI),( Letter 3334J-5, ~ ~ January 14,1986.
.33.;;UR S.-dtomic Energy Commission Regulatory Guide 1.60, Revision 1,.
W f %$ , (Decembery1973. y
,4 m i.34.,LStreeter,LV.LL.', FLUID MECHANICS,'4th Edition, McGraw Hill Book.Co.,
j@? , ' New? York,1 New York, 1966.; g" ~ # ;35; Private communication, Hri M. Shinko, CDC, Rockville, Maryland,
, FebruaryL12,o1986.
'36.1/Sargentl& Lundy, Diagram of Reactor Coolant Loops 3 and 4, Zion-
> Station, M-53, March 3,1970.
'o A" :;
a o ..
. . . ~
37f Smith,~ L.C. and~ Chang,l K.C., " Development and Plant Specific
< Applications of. Pressurized Safety Valve Discharge Loadings, 4 y ASME PVP-90, June 1984.
f 38. sHornback' . C. lJ., (CDC), "UIS Quality Assurance Program Manual," July 7, K < 1984. [F" 39. ?Bergen-Paterson Pipe Support' Corporation, Catalog 77 NFR3. 4 ; < 40.: IITT Grin'nel Corporation, Catalog PH79, a . . .+ u L 41.7 'NPS? Industries, NPSI Catalog-8.4. " l42i . " Power Piping,"1 ANSI /ASME B31.1, ASME Code for Pressure Piping, The V American Society of Mechanical Engineers,1967 Edition. l
?'... 1431 "NuclearLSystems Materials Handbook," TID 26666, Hanford Engineering h ! Development Laboratory, Richland, Washington. l
- i. j Architect Engineer's Project Plan for the Evaluation of the Pressurizer L"44.
iSafety and Relief Valve. Discharge Piping Subsystem - Zion Station Units 1 1: andJ2", ODAI Report 1719-400-003-00, Rev. 3, 10-20-86. t '45[("StructuralDesignforDynamicLoads",Norris,etal,McGraw-HillBook Company, Inc;, New' York, N.Y., 1959.
- 4'6 . . Atlas of Stress-Strain' Curves", Boyer, H.E.,
" (Ed.), ASM Internat i ona l ,
Metals Park, Ohio,-l1987. 4 y y .c , l Page 33 of 49 -
] LN19-400-002-00
-_-_ _ _ _ -_-__ a
- ,g y 3 l
.g h
3 m 1 q [ l TA8LE 1 {
.}
MATERIAL DATA' g u ! Outside Wall Material ~ R M Diameter Pipe Thickness Pipe / Temperature e 1.ocation (In.) Schedule (In.) Fitting Range (*F) Class F Upstream of '6.625 160 0.718 SA-376 TP316 120-668 1
~
- Safety / Relief SA-403 WP316 s n Valves. f
. Upstream of 3.5 160 0.437 SA-376 TP316 120-668 1 H - Relief Valves SA-403 WP316 ;
1 Downstream of 3.5 40' O.216 SA-312 TP304 110 3 Relief Valves SA-403 WP304 l l l Downstream of 6.625 40 0.280 SA-312 TP304 110 3 Safety Relief- SA-403 WP304 .
. Valves. l i
Header 12.75 40 0.406 SA-358 316 80-110 3 . SA-403 WP316 ! h , l
.SA-376 TP316 SA-312 TP304 SA-358 316 SA-403 WP316 SA-403 WP304 SA-403 WP316
' Temp. S *S S *S. S *S J
(*F) (KSI) (Khl) (KNI) (Khl) (KNI) (Khl) 4
-100 18.75 43.125 18.75 43.125 16.90 38.870 l 200 '17.50 40.250 16.55 38.065 15.75 36.225 ;
300 16.90 38.870 15.55 35.765 15.20 34.960 400 16.30 37.490 14.95 34.385 14.70 33.810 500 16.00 36.800 14.55 33.465 14.40 33.120
-600' 16.00 36.800' 14.35 33.005 14.40 33.120 i 650~ 16.00- 36.800 14.30 32.890 14.40 33.120 ;
700 16.00 36.800 14.20 32.660 14.40 33.120 l 1
*S = 2.3 5 for limit moment (Appendix F of Reference 12).
A 1719-400-002-00 Page 34 of 49 m- _
l
- ) -
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TABLE 2 i
'SH0CK ARRESTER PLASTIC STRAIN
SUMMARY
FOR FAULTED CONDITIONS - NONLINEAR INELASTIC ANALYS15 15UPPORT DRAWING PIPING ELEMENT . MEMBRANE ,'
, ' NUMBER LOCATION- NUMBERS
- STRAIN (1%)
1RC157-RV2' S/V #3 Discharge- 232, 435 0.66
-RCRS-1123A S/V #3 Discharge 241, 443 0.16
.RCRS-1121 Vertical Header 273, 437 0.68 279, 438 **
RCRS-1120- . Vertical Header
.RCRS-1119 Vertical Header 282, 445 0.08 RCRS-1118A Horizontal Header 302, 439 0.26 RCRS-1117B Horizontal Header 321, 444 0.37 RCRS-1117 Horizontal Header 325, 441 0.88 i RCRS-1117A Horizontal Header 335, 442 0.12
*See Figure 7. for node locations. and element definitions
** Shock arrester was ; removed'from the model when 2% plastic membrane strain was exceeded.. (See. Figure 10 for support location. )
I i I 1719-400-002-00 Page 35 of 49 -~~_ _______ ]
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SUMMARY
FOR FAULTED CONDITIONS - ENM b , .- NONLINEAR INLLASTIC:ANALY5IS. l x <l- ,
, YY a-l&m ifff' * .
i t WpA. l Mh>: ' W., .....9,: ,m - r s q .. - . W,, ..
# MEMBRANE.
%N W,1 ELEMENT M . 1* NODE" -PIPING- ~PLUS BENDING i
; NUMBERS : LOCATION: STRAIN (%)
[ ? 7 NUMBERS ~ , h jhq 'L15 ? ' ld ' ~
>110j 3109- - S/V #1LLO'0P' O.04
,6 W # 1964 .
(19443193; S/V #3 LOOP 0.08
.W "243 '
! 216': f3218' '
S/VX#3. DISCHARGE 0.38 N N d285t ' F248i13249. .. VERTICAL' HEADER. 0.19 0.25 e if $ '289 $l..' "250 D.3251' ' VERTICAL HEADER L252;.3253-' , VERTICAL-HEADER 'O.57 f f 2 Y 294/298' z 0.15 p h s.g 1317-f 9 : 269c L ?3270? HORIZONTAL'-HEADER 0.12 gg w L:329 & - H0RIZONTAL HEADER. 278s:3279: f.( 1338J, e ' y 12011.3285: 7
- HORIZONTAL 4 HEADER '0.42-y: . mv
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,,.~
< \
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#Results;are basedLonLthe detailed three-dimensional finite element models WI WS. k .:,)<~J,asLdescr.ibe'd'.in Sectionl2.3.2e.. '
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T.! # ) e j , y RELIEF TANK .J n, j
- s l iP '=' PRESSURIZER S- =. ' SAFETY VALVE SUPPORT j Rm
- R/V 4 RELIEF: VALVE S/V = ' SAFETY VALVE i r -
FIGURE.1 DISCHARGE PIPING SUBSYSTEM SCHEMATIC t j
--L17192400-002-00 Page 37 of 49 o- ..
I 1 e
6-inch OD pipe j 0 - - ~4 4-4 6-inch OD pipe
. 6-inch D pipe p. ,__.,____.,_..___q,-
g kT Pressurizer Safety. valve - Safety , m
-- .~ .. m Safety i" - 'h valve f
- 6-inch 'h valve
,, OD pipe, ,
'e O. 'O $ O O 6-inch OD pipe Reducer ]
n - Relief valve a -
; - system 6-inch OD pipe - , t 12-inch
,O D pipe _
j j e -- Elbow or ,.t pipe bend , j v .l l Sparger Relief tank .
)
l li 1 FIGURE 2 SAFETY VALVE PIPING SCHEMATIC l i l 1719-400-002 Page 38 of 49 l, i La
py: E Reduction Reducer le O Relief Block
=: valve ] y ;
. b, -
6-inch - ! OD pipe \ Relief valve
- 3. Inch o Pres surtzer OD pipe O D pipe 6 inch OD pipe Reducer
- j. '
Safety valve , system - < :. Redaction
'.~ tee ; .; Safety 4 valve
[ j s ystem i
- 12. Inch OD pipe g Elbow or [_ _
_ _ _1 Pi pe bend
-S arger Rollet tank FIGURE 3 RELIEF VALVE PIPING SCHEMATIC l 1719-400-002-00 Page 39 of 49 l
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l I f FIGURE 6 DETAILED FIN TE EM NT ODEL F RICATED BRANCH 1719-400-002-00 Page 42 of 49 ; _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ - _ _ _ J
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; , t w I.1 h',,, , ) :'
( ce t - s 207 DOWNSTREAM NFETY VALVE P! PING' 202 o O.: I N0DE t.0 CATION :
"XXXL-NODE NUMBEk
, t H -- ' HEADER PER TIGUPE 12d 7 '206
/ ; R '; J RELIEF P! PIG PER FIGURE'12c n .' ' ,
205 204/ "203/3203 - 3204 s j -)
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i$ 1 1 FIGURE.7a N0DE LOCATIONS FOR STRUCTURAL MODEL - fe .m NONLINEAR INELASTIC ANALYSIS 1719-400-002-00 Page 43 of 49 x i
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L 135/3235 134f 313'4 l "136/3136 133/3133 l 132/3132
' 137 ,
s 138/3138 "141/3141 gj31/3131 39 06 /3106
'101/3107 105/3105 UPSTREAM SAFETY VALVE PIPING N00E LOCATION o108 XXX N0DE NUMBER j "111/3111 109/3109 104/3104 110/3110 10?/3102 101/3101' 181/3181 183/3183 180/3180 i 184/3184 185/3185 186 Y
187 a l 188/3188 ' 189/3189 190/3190 Z [ x o 191/3191
'192
" 193/3193',196 '
195/3195 L j 194/3194 l
.1 , FIGURE 7b N0DE LOCATIONS FOR STRUCTURAL MODEL -
NONLINEAR INELASTIC ANALYSIS l l 1719-400-002-00 Page 44 of 49 j l m - .)
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yNote:S Questions' numbers.6.and~16'were not provided in the referenced. letter.- 0,9lM , , f: y. ,3 m~ 9.; 4 ua
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>w(" '1A andilB:1 Press'ureDropAndBackPressureCalculations hh "
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, .;The[pressureldrop and.back pressure calculations for the O'Donnell &
Pf%bj , Lg,Phssociatesj(ODRI) report were' based on.a RELAP analysis performed by ODAI. i '
?Typicalfresultsifrom the;ODAI' analysis are'given'in Figures 16'and 17 of .
it sg 4 :y : Attachments 2. F , ' ; M. . ' The ODRI; analysis considered:the~as-built configuration, thus assuring M d j realism.l:The, source _of:the inputs used'in the'oDAI; analysis is given in W N Attachmentil '. ; 4 m u ;. t, .+ . . .'l . . 7g y 7 2: ,, Liquid Relief: Through ' Safety Valve and PORV Ei i
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NThe deferenced: letter requested'that Commonwealth Edison Company $p"3,- : WI g ,',sss (addrthetpostulated;PORV/ Safety Valve conditions following a feedwater line-N'
- breakb This ovaluation would require the performance of a Zion -' specific m' > sfe'edwaterJ11nel break? analysis.
;^
y 's X ' " Zion. Station received it's operating license'in 1973. There was no
;,y grequir'ementat(thatitimeto. include:feedwater.line.breaksaspartofZion's L11 censing basis, g *, Q '
L ; . commonwealth Edison Company'recognizesLthat Byron and.Braidwood .! Stations were required to' address postulated feedwater line breaks. This M
. disparity (is a' result;of theLamended' licensing requirements:in offect at the
~
I itime of;the licensing of these:two facilities.
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,j 4 "M Commonwealth Edison Company:has no current plans to backfit. a l s
,1
"- fesdwater line break analysistinto Zion's licensing basis. However, 'i W ir , Commonwealth Edison remains prepared to provide any,information regarding the R >
] (performanceof'the'PORV'andSafetyValves~withintheexistinglicensingbasis.
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- '3:'1 Bending Moments on Valves a ,,
W < . The load Maximum. bending moments-are provided in' Attachment 2. b' ..
< j g g. ~ combinations used for'the'ODAI analysis are provided in Attachments 1, 2, and 3.
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-.! 4;. Valve'Actua' tion' Cases.
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The ODAI_ analyses considered only'the loop seal discharge. This is -f
=m . consistent with the plant" design bases. The assumptions regarding valve factuation.are provided in' Attachments 1, 2, and 3.
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hlq p AMC ; ;The ODAI analyses did not consider.any PORV discharge cases. . Input W< , assumptions-for the'ODAI analyses.are provided in Attachments.1, 2, and 3. .l, I j \ .
, Th '. . .
;5B: Assumed' Fluid Transient Conditions s l to I 4
/
aTest;917 was forLa hot water loop seal discharge. From Test 917 .the
~
l Evalve ' stem' simmering time of 0.9077 seconds and valve stem pop time of 0.01475' i seconds were measured. -Because thefloop-seals in the Zion plant are.not
, insulated =it is more realistic ~to use. test results for a' cold water. loop seal. f g dischargeLi'.e.~, EPRI TestL 908 or Test 1017.-
Wa . T - , . ' Comparison ofLthe; valve stem position versus time for Test 917 (hot j iwaterfloopl seal) with TestsL908 and'1017 (cold water loop-seal) shows that the -j
. simmering time!is11onger for the cold water loop-seal than for.the hot water /
'meu looplseal,'while there is no~significant differences in the pop time. l
..Therefore,.the ODAI analyses are. conservative because.they used valves for
,,y {sismerandpopltimesof0.88.secondsand0.0145 seconds,respectively,
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'T M ,SC and SD: 1 Assumed' Fluid Transient Conditions-
~
.EPRI. recommendations were utilized for the' volume. length. A maximum ftime' step sizeiof'18-3 seconds and a minimum of 1E-9 seconds were specified
, "3- for the' analyses'. lRELAP 5/ MOD 1 selects a' time step between:these values p, : based cx1 built-in criteria. The determination of the' maximum time . step was a . based on past' experience and' preliminary results of the maximum velocity in athe piping. system. .The minimum time step controls the solution during
;g., Ewater-to' steam; transition for discharge through the valve. A time step as
',y small as:1E-9Laeconds was required for the code to achieve a stable solution u; ,forLthis condition.
R_
, s7: -REPIPE' Code Verification 1 ;
i'
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- Verification results for the'REPIpE code are provided by Attachments 2'and 3..
8: -Thermal Hydraulic Ana1Ysis Report The thermal hydraulic analysis report for the ODAI analysis is -w provided by Attachment,2. 1 l
.9A: Computer Code for Structural Analysis JTIAe ODAI analysis used the ANSYS Code, which for the Nonlinear g;q > jTransient Dynamic Analysis used in the Phase II analysis (Attachment 3) uses I" .jthe-direct integration method of solution. 1
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'9B: Computer code for Structural Analysis 1
~The ANSYS Program is used to do a nonlinear time history dynamic
' analysis. The source of the loading history (water hammer event) is not 1
-pertinent to whether ANSYS can accurately solve the problem, that is related q
to the ability of RELAP/REPIPE to adequately represent the problem. The ODAI l reports contain several' verification problems pertinent to the type of analyses performed.
.10: Fluid Forces on Structural Model The nodal locations and piping loads are provided by Attachments 2 l and 3.
l IIA, llB, & llc: Key Parameters in ANSYS Inputs j l The information required to answer these questions is provided by j Attachments 2 and 3, i 12: Load Combination i j- The ODAI analyses were based upon the existing system configuration j which has already been successfully evaluated for all conditions except the j 3 slug flow event. The additional information requested for the slug flow { transient is provided by Attachments 2 and 3. 1 l 13A & 13B: Stress Evaluatiop_. The information required to answer these questions is provided by ,
-Attachments 2 and 3. J
{ l 14: Sketch of Structural'Model The information required to answer this question is provided by Attachments 2 and 3. l e 15A, 15C, & 15D: Piping Support Evaluation l The information required to answer these questions is provided by l Attachment 2 and 3. ISB: -Piping Support Evaluation Attachments 2 and 3 provide this information. A comparison of support stresses for the applicable services condition during the slug flow transient is provided. 17: Structural Analysis Report These reports are provided by Attachments 2 and 3. 3848K l
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