ML20101G706

Forwards Responses to NRC Audit of GE on ABWR Piping Design Criteria & Sample Analysis on 920323-27 & Rev 2 to Design Bases Spec 386HA931, Event Combinations & Acceptance Criteria

ML20101G706
Person / Time
Site:	05200001
Issue date:	06/09/1992
From:	Fox J GENERAL ELECTRIC CO.
To:	NRC
Shared Package
ML20101G709	List: ML20101G706 ML20101G719
References
NUDOCS 9206260247
Download: ML20101G706 (47)

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' NRC Audit of GE on AEWR PIPING DESIGN CRITERIA AND SANFLE ANMas38

, March-23-27,1992 Item No.: I

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DESCRIPTION OF CONCERN:

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CONCLUSION:

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a NRC Audit of GE on A3RR PIPING DESIGN CRITERIA AMD SAMPLE AMELYSES March 23-27,1992 2

s Item No.: 3 sy:

QLigEIPTION OF CONCERN cl O s' ssAR TA 3. 2-1 [ Dr M WWY n s fe<m , , xk. s sn. h W #l3 ^*%

5 RESPONSE BY GE:

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'l'.9 CONCIHSION:

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l "RC AUDIT CP CE ON l ABVR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS HARCH 23 27

)

i ITEM NO: A4 P

DESCRIPTION OF CONCERN:

1. What is the ASME classification of the SRV quencher?

2. What analysis and design method was used relative to 1.ca design specification?

RESPONSE BY G.E.*

4 1. Response prepared by JB Knepp

2. The quencher is analyzed to the rules of ASME.III, Class 3. The quencher is treated as a fabricaced assembly of piping components and is analyzed so the rules of ND 3600. The analytical methods are described in the summary stress report and in supporting documents such as:

Containment Loads Report, Specification No. A21 2040; 386HA579, Dynamic Load Mettads and Criteria; Computer Manual for PYSIS,

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9 NRC Audit of GE on ASWR PIPING DESIGN CRITERIA AND 8&MPLE AMALYSIS March 23-27,1992 Item No.: ..

9 s By:

D E RIPTION OF CONCERN VI) ;t. k 7 ) t M M E u ls4. f % y A % ! R V Q 4 u ) . w J . 2 ~ Jp.k n).

b . % a t a ~ - ~ d s e J 4 Z r J 2-<- e k y J -._l,s 4 ; 7 RESPONSE BY GE

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.' NRC Audit of GE on ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSES March 23-27,1992 Item No.: T By:

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4 NRC AUDIT OF CE ON AB'.*R PIPING DESIGN CRITERI A AND SAMPLE ANALYSIS MARCH 23 27 I i

ITEM NO:_A 1 DESCRIPTION OF CONCERN:

1. Need to see criteria for all supports analysis / design. 1 1

2. SSAR needs to include description / requirements for guidoL '

RESPONSE BY C.E.*

1. There is no single GE document that sets forth all the criteria for the design / analysis of supports. The SSAR covers all pipe supports in considerable detail, with the possible exception of the Main Steam /Feedwater guides and structural frame supports such as those in the watwell. The most important documents defining design / analysis criteria are the C.E. pipe suspension purchase specifications and the pipe suspension drawings. These documents: (1) Provide a complete basis for design, manufacture, qualification. *- sination and installation of pipe supports for all ASME III piping; Require the design and analysis of supports for nuclear piping to be in conformance with NF Subsection of ASME III and suports for non nuclear piping to be in conformance with ANSI B31.1; and (3) Provide design loads obtained from the piping analysis and specify the minimum support stiffness,

allowable materials, installation tolerances.

Examples of recent documents prepared for the K6/K7 plants are:

23A6061 Main Steam, Feedwater & Safety / Relief Valve Discharge Pipe

, Suspension.

103E1512 Main Steam Pipe Suspension 103E1437 - Feedwater Pipe Suspension 103E1525 SRV D/V Pipe Suspension 103E1526 SRV V/V Pipe Suspension

2. C.E. is now considering adding additional requirements to the 1SAR to provide more detail on the main steam and feedwater guides inside containment.

NRC Audit of GE on ABWR FIPING DESIGN CRITERIA AND SAMPLE ANALYass March 20-27,1992 Item No.1 b By: i DESCRIPTION OF CONCERNt s' %A & An- u% & A y - Agq ,

M SSAR+a4. A 4Au .b 4 g9 % .4 g RFAPONS2 BY GE:

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urpnt h ni pudadd STAFF EVAEATIQ44 CONCMSION:

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NRC AUDIT OF GE ON ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS ,

MARCH 23-27  !

ITEM NO: A7 D_ESCRIPTION or CONCERN:

Why does the Piping Criteria occument utilize only Reference 6.0-c and not all applicable NRC R.G.'s and S.R.P's,7 RESPONSE BY r E_ .2 All applicable NRC R.G's and S.R.P's will be referenced-in the Piping Criteria document.

ITEM NO: A-8 DESCRIPTION OF CONCERN:

The 1/3 pipe size criteria is not sufficient, additional piping decoupling/ interaction criteria (e.g. SSAR 3.7.2.3.1) are needed.

The effect of branch line supports close to the main line should be considered.

RESPONSE BY G.E.: '

I-The criteria specified in Section 3.7.2.3.1 of the SSAR are used to determine whether a piping or equipment subsystem can be decoupled '.

from the Building or primary system model. If the diameter of the branch-line is less than 1/3 the diameter of the main line it can j be decoupled from the main line.

For a decoupled branch line, no dynamic supports will be located close to the mein linc. Otherwiss the adjacent support would be loaded by the main line during dynamic events.

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NRC AUDIT OF CE ON ABL'R PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS MARCH 23 27 ITEM NO:_& 2 DESCRIPTION OF CONCERN:

Request criteria document (s) discussing dynamic analysis criteria in more detail (e.g. basis for highest frequency of interest, damping, delta e for time history analyses, ISM method of analysis, modal analysis method, how is the " effective / weighted" modal damping determined.

RESPONSE BY GE:

Document 386HA579, Dysamic Load Methods and Criteria, by DK Henrie, provides the best available decatie on the dynamic methods and criteria used by GE in the dynamic analysis of piping. A copy of this document was provided during the March meetings. Based on verbal comments, it is GE's understanding that the 386HA579 document was satisfactory response to this item.

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NRC Audit of GE on ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS March 23-27. 1992 Item No.: A10 By:

J DESCRIPTION OF CONCERN:

Are forcing function variations considered for direct integration analysis due to hydrodynamic loads. This variation (expansion and contraction) of the forcing function is the equivalent of response spectra peak broadening.

RESPONSE BY GE:

The wetwell loading input has been defined to cover all frequency ranges (similar purpose of expansion and contraction). Some time history loads are i impulse type loads, such as safety relief valve discharge loads, expansion of the time history is equivalent to increasing the load. It is not necessary to add extra conservatism to this type of load. Similarly, it is not appropriate to contract the inad (equivalent to reducing the load).

, STAFF EVALUATION:

3 CONCLUS0QN:

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NRC AUDIT OF GE ON ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS MARCH 23-27 ITEM NO: A-11 '

DESCRID710N OF CONCERN; Clarify definition of components vs. damping values (snubberastrut) in damping table presented in the Piping Criteria document.

RESPONSE BY G.E.:

The following note will be adQed to Table 1 :

Cm -the Pipc3 cntern Aoc)

Snubbers and Struts are connected to the piping and to the supporting structure with pin connections, therefore the R.G. 1.61 damping values for bolted steel structures are used. Piping test data results show that the damping values for struts are at least equal to those for bolted structures, and the damping values for snubbers are greater than those for bolted structures.

ITEM NO.: A-12 DESCRIPTION OF CONCERN:

1. Provide the basis for application cf all displacements in the same direction.

2. Provide justification for SRSS combination of inertia and displacement effects.

3. Provide criteria for order of combination for inertia and displacement loading events.

RESPONSE BY G.E.:

1. An additional seismic displacement case will be evaluated in which it is assumed that the biological shield wall moves in a direction opposite to the reactor pressure vessel and the drywell wall. Because the seismic inertia loads are so high there will be no significant change in the calculated piping stresses or support loads.

2. "The inertia (primary) and displacement (secondary) stresses are dynamic in nature and their peak values are not expected to occur at the same time. Hence combination of the peak values of inertia stress and anchor displacement stress is quite conservative. In addition, the anchor movement effects are computed from static analyses in which the displacements are apolled to produce tne '050 conservative loads en the components. In view of this, the comninati:n of primary and secondary stresses snall be by SRSS."

Referenced from CE doc. no. }S6HA579, Rev. 0

NRC AUDIT OF uE ON ABWR PIPING DESIGN CRITERIA AMD SAMPLE ANALYSIS ON MARCH 23-27 ITEM NO: A-12(Continued)

PESPONSE BY G.E.:

3. Since all dynamic loads are combined by the SRSS method, the order of combination of inertia and displacement loads does not effect the results. The calculated dynamic loads are then combined with thermal and weight loads either by algebraic summation or by the absolute-sum method.

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9

NRC AUDIT OF GE ON ABWR PIPING DESIGN CRITEPIA AND SAMPLE ANALYSIS MARCH 23-27 ITEM NO: A-13 l l

DESCRioTION OF CONCERN: I l

1. Interaction concern: flexibility of building local structure affecting/ amplifying floor response spectra How is this addressed? (e.g. floor flexibility)

2. Piping amolified spectra for branch line analysis,How is this addressed?

3. Provide justification for the 1.2 factor for hydrodynamic amplification to account for local flexibilities RESPONSE BY G.E.:

1. Flexibility of building local structures, such as steel platforms used for supporting piping and other equipment, are accounted for in the piping analysis. For the sample problem it was assumed

'that the steel platform has a fundamental frequency greater than or equal to 33 hz. Therefore, there is no amplification of the seismic loads. For hydrodynamic loads, a dynamic amplification factor of 1.2 was used. This factor is necessary to account for amplification at f'requencies greater than 33 hz.

2. For branch lines decoupled from the main line, amplified i spectra are applied at the ettachments to the main line. The ERSIN computer program.is used to generate the amplified response spectra.

3. The 1.2 factor was calculated and used in the analysis of the ABWR's under construction in Japan.

NRC AUDIT OF GE ON i ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS ON MARCH 23-27 ITEM NO: A-14 CESCRIPTION OF CCNCERN:

1 How many Cycles will be used for seismic and other leads?

2. What is the basis for using i SSE floor spectra for OBE floor soectra?

3. Were building rocking effects added to the vertical spectra?

RESPONSE BY C.E.

1. The SSAR and the Piping Criteria document will be revised to specify the correct number of cycles. In Table 3.9-1 of the SSAR, the number of events or cycles will be increased by 50 % for the following events: Events 1- 9 and Events 14&15.

2. There is no basis for using ) sse floor spectra for OBE floor spectra. This was done because the OBE floor spectra were not available. The Piping Design Criteria document will state that for future analysis of ABWR piping, the appropriate OBE floor response spectra shall be used in the analysis.

3. Building rocking effects were not added to the vertical spectra.

This was determined to be unnecessary since there was adequate 2

conservatism in the structural analysis.

i ITEM NO: A-16 DESCRIPTION OF CONCERN:

How and why is the flooded load included in the analysis?

How many cycles are considered?

4 RESPONSE BY G.E.:

Two hydrostatic test cycles are considered for each boltup cycle.

Therefore 135 events are considered to occur during the 60 year design life. During the hydrostatic test event, the main steam line and the SRV discharge lines are filled with water. Therefore for these lines a dead weight analysis is done for these lines filled with water.

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NRC AUDIT OF GE ON ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS HARCH 23 27 f

ITEM NO: A 15 DESCRIPTION OF CONCERN:

I 1. How do you insure SRV valve to be purchased will have a rise time greater than 20 msee?

I

2. Same applies to TSV.  ;

l RESPONSE BY GE:

i

1. GE has not placed any restrictions en how fast the safety relief valves may open or on how rapidly the turbine stop valves may close. The specification for the Safety Relief Valve requires the " Total elapsed time l from start of main disk motion to full stroke of the SRV (i.e., lift to full rated capacity position) shall not exceed 0.15 seconds." CE calculates the forcing function for RV 1 based on a 20 millisecond rise time. Rise time is defined as the period of time from start of flow through the valve until essentially full flow. G.E. has established the 20 milliseconds as a conservative valve based on evaluation of available data from valve

-l manufacturers.

t The results of the overall analytical process includes many important variables, including: analytical model of pipe and supports (stiffness, wall thickness, diameters), the analytical assumptions in the computer program RVFOR, out put time step, steam line pressure, total FL/D and inside diameter of discharge pipe, analytical definition of quencher, code method for calculating stress 55 at branches and elbows.

C.E. does not feel is necessary, nor desirable, to upper bound all the variables in the analytical process. It is important the overall analytical process give results that are in satisfactory agreeeent with actual tast results. G.E. has performed numerous in plant tests which have shown the overall analytical procedure for calculating stresses gives reasonable results l

compared with stress measured.** There is no data to indicace the stress l valves calculated by G.E. analytical methods are nonconservative.

In addition, the Start Up testing program for each BVR requires strain gauge instrumentation be install on typical SRVD lines and SRV inlet piping to l

confirm, on a plant by plant bases, the analysis gives results in satisfactory agreement with measured results.

2. The philosophy described above also applies to the TSV load.

l Note: (1) Special in plant tests pertarmed at Duane Arnold, Monticello, Kuosheng and Coarso.

I o . . ._. __ __ . . _ . ___

. . . . . -.. -... .- -.. . . _ . - - - - . . . . ~ . . - _. - . - -. _ . . - - . - . . . . . ..-

i i

i I

(2) Special SRV cost at Wiley Laboratories facillcles ac Huntsville, Alabama under direction of H.L. Hwang.

(3) NEDE.23751. BWR/6 Mark !!! Safecy/Re1Let Discharge Piping

, Transient Force Paramectic Scudy. Dec. 1977. " Based on tesc ,

data, the shortest opening time is 0.02 second. !c is conservacive to assume a short opening time."

a (4) HL Hwang Studies:

f Letter to E.O. Swain. February 14, 1978, SRV Opening Time.

Lecter to H. Chang, dated November 9, 1976, Preliminary 1 Monticello SRV Discharge Test Results, SRV Piping, a

I l.

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• NRC AUDIT OF GE CN ASk'R PIPING DESIGN CRITERIA AND SAMPl.E ANALYS15 MARCH 23 27 ITEM NO:_A 12 DESCRIPTION OF CONCERN:

1. Will GE consider / perform fatigue evaluation for ehermal effects when pipir; involves hot and cold thermal mixing?

2. Provide thermal stratification criteria / methodology for piping analysis.

RESPONSE BY GE:

1. It is GE practice to evaluate the thermal stresses in piping at locations I where hot and cold liquid streams are mixing. The normal procedure is to assume the temperature of points in the piping in the vicinity where the mixing occurs will fluctuate rapidly between the hot temperature and cold temperature of the two mixing streams. It is further assumed a large number of thermal cycles between the hot and cold temperatures will occur in a short period of time. Therefore the thermal stresses must be will below the endurance limit of the material. If calculations show the thermal stresses approach or exceed endurance limit values, GE requires a thermal sleeve be designed and installed to protect the pressure boundary from fatigue damage.

2. By KFF

f' A8WR P! PING DESIGN ChlTERIA AND SAMPLE ANALY$15 March 23 27, 1992 Item No.: A17 By:

DESCRIPTION OF CONCERN:

1. Will GE consider / perform fatigue evaluation for thermal effects when piping involves hot and cold thermal mixing? See p. 3.9 45 of SSAR should systems requiring this' evaluation be specified now?

2. Provide thermal stratification criteria / methodology for piping analysis.

RESPONSE BY GE:

1. By EOS-

2. The thermal stratification load is caused by different temperatures at the top and bottom of a horizontal aipe. The loads and stresses caused by thermal stratification are similar to t1ose caused by thermal expansion. Therefore, the stresses and load criteria for thermal stratification should be combined witi1 concurrent thermal expansion stresses and loads by algebraic summation.

The combined results should meet the thermal expansion limits specified by ASME Code. The analysis method is described in an internal GE document (ABWR88027).

STAFF EVALUATlqN:

CONCLUSION:

4

Imc Audit of CE on ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS March 23-27,1992 Item No.1 II Byt ,

DESCRIPTION OF CONCERN , Oaj ,

fa r' 5 & W 4 & WN

+na&. Ad Q -f l e

RFMPONSE BY GEt G E wD gw']i AL bnL J WS aldw.,c.rd

h. Pwgsdj. Ja ,., ibsjg ID App <mA:s sa d 22A10llt, ' NNSYS LA W N^b s Yf

%,d. don helgn blu h Ll>m SIcel'i I?) PVQC Ouula].,n & 'fdf

%[afCS4MfTwp,, Oy ,a}g} N -

b) lyf, Gyg,, ,.,,;, , "$4,

$'U Y AL7A 4 N f A.te, Ant 2 Ed f kat4h S A tar',

STAFF EVAfMAffoMJ

%3- y, s;'

CONCIESION

NRC AUDIT OF GE ON ABWR PIPING DESIGN CRITERIA AND SAMPLE ANLYSIS ON MARCH 23-27 l

ITEM NO: A -19 DESCRIPTION OF CONCERN!

How i s the damping value determined for piping systems which include small and large diameter piping?

Provide procedures to determine damping for both ISM and USM methods of analysis. Provide justification for methodology.

RECPONSE_BY G.E.:

Independent Support Motion (ISM) Damping Values:

For each response spectrum used,the damping value corresponds to  :

the pipe size at the support. Therefore,in an ISM response spectra analysis more than one damping .'alue can be used.

Uniform Support Motion (USM) Damping Values:

For each response spectrum used to generate the enveloped response t

.soectrum, the accelerations correspond to a datping value dependent i on the pipe size at that support. Once the enveloped response spectrum is generated, the smallest damping is ther, used in the 4

dynamic analysis.

i These are the typical industry practices. For_the USM method

' the use of the smaller damping values in the dynamic analysis is conservative.

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NRC AUDIT OF GE ON ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS '

ON MARCH 23-27 ITEM NO: A-20 DESCRIPTION 07 CONCER'4:

1. In the Criteria document, clarify the description of the RV2 load and specify any factors used in the F;V2 analy sj t.

00es SRV all valve bound all RV2 loads?

2. Functional / Operability requirements ptr S.R.P. 3.9.3 are not in the GE Criteria document.

3. Load combinations for Equation 10 & 11 are not in the Criteria Doc.

4 What revisions will be made to the Tables in the Criteria document?

RESPONSE BY G.E.:

c

1. The description of all RV2 leads and all applicable factors will be incluced in tne Criteria document. SRV all valves does bound all RV2 loads.

2. & 3. These items will be included in the Criteria document.

4 Tables 3 &' 4 will include primary and s' :ondart load combinations.

Table 3 will specify that the lesser of two acceptance criteria shall be used, a note will be added on functional capability criteria.

Tables 3,8,9,11,12,13&14: Individual loads will be separated by commas instead of +'s.

Table 12: Allowable moments will be deleted, acceptance criteri?

will specify the applicable ASME Code paragraph.

Table 9. T he a c c ep t anc e cr'derkt w\\\ be specified.

Table 13: Acceptanceg will be deleted.

criteria

NRC AUDIT OF GE ON ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS ON MARCH 23-27 ITEM NO: A-21 DESCRIPTION OF CONCERN:

Provide BWR 6 Load Combination definitions RESPONSE BY G.E.:

C.E. Document No. 386HA931, Rev. 2, Event Combinations and Acceptance Criteria,provides the BWR 6 L0ad combinations.

ITEM NO:A-23, DESCRIPTION Cr CONCERN:

Provide description and bases of spectra interpolation / extrapolation procedure ( for dif ferent elevations / locations).

RESPONEE BY G.E.:

GE internal precedures provide guidelines on response spectra selection. The RINEX computer program is used to interpolate and extrapolate response spectra.

l

7_.

i i

A8WR P! PING DESIGN CRITERIA AND SANPLE ANALYSIS l March 23-27, 1992 i

1 Item No.: A22 By:

l ,

QESCRIPTION OF CONCERN:

Does GE intend to use ASME Section 3200 related to plastic analysis method.

If so, provide criteria since the Code lacks requirements in cert.

n areas, RESPONSE BY GE:

l It is not GE's intent to use ASME NB 3200 plastic analysis as a generic l l method.. such as limit analysis, to meet the primary stress allowables. There l j are two possible applications: (a) calculate the plastic strain for fatigue  ;

i usage evaluation, and-(b) pipe whip restraint analysis-due to a postulated 4 pipe break. The present Code requirements are adequate for these two applications.

STAFF EVALUATION: -

! CONCLUSION:

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. - - - - . _ = _ - . _ . = - - - . - - . - . . _. - __-.- _ _ . .. -.

i NRC AUDIT OF GC ON ,

. ABVR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS MARCH 23 27 ITEM NO:_A:26 DESCRIPTION OF CONCEP10

1. What is the method of seismic analysis for the main steam piping beyond isolation valve outside containment to turbine buildirig.  ;

. \'

l 2. If dynamic analysis will be usad, then what document provides the seismic j spectra input.

I RESPONSE BY GE:

1. Main steam piping between containment and the turbine building will be i analyzed for seismic loads using response spectra methods and code allowables l equivalent to that applied to ASME Class 3, piping.

2. The seismic spectra input has not yet been defined. This subject is still under study by GE and under negotiation with the NRC.

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~ , , . , , , , ,- y

NRC AUDIT OF GE ON ABWR PIPING DESIGN CRITE9IA AND SAMPLE ANALYSIS .

ON MARCH 23-27 ITEM NO: A -25 DESCRIPTION OF CONCERN:

Why does ciping analysis use ZPA for high frequency effects, rather than the acceleration at the highest frequency at which the modal analysis ends?

RESPONSE BY G.E.:

The acceleration at the analysis. cut-off frequency shnuld be used to calculate the high frequency C #fects.

_ _ _ _ _ , _ _ . _ _ _ _ . . _ _ - - - - - ^ - - - - - - ' - - - - - - " - - ' - - - -

I l

NRC AUDIT OF GE ON ABWR PIPING DESIGN CRITERIA AND SAMILE ANALYSIS M/RCH 23 27 ITEM NO: A;,25 i

j DESCP.IPTION OF CONCERN:

1

1. What are the analysis / methodology and acceptance criteria for buried i piping analysis (beyond short descriptions in SSAR)? ]

4

2. What provisions are provided for protection from extarnal events (e.g.

wind ., tornado, missilet? If no protaccion is provided for some of the events, what are the analyses /msthodolcgy and acceptance criteria?

^

t RESPONSE BY GE:

4

1. GE wt44 has not yet determined if the SSAR should be t? vised to provide more definition of analysis methods to be applied to buried piping. At present ASME III Class 2 or 3 piping must meet the requirements of NC/ND 3600,

! These rules do not distinguish between abov* ground and underground piping.

The Class 2/3 rules may be overly conservative when applied to underground pipe. If the decision is made to provide additional requirements for buried piping, CE will evaluate the most recent actions by piping ccde committees and determined if cods approaches need to be supplemented when applied to ABVR.

Examples of Code actions are:

(1) Proposed B31.1 Non mandatory Appendix VII, Recornended Procedures for the ,

Design of Restrained Underground Piping. (2)

(2) ASME III DRAFT General Requirements for ASME Section III Clast 2&3 Lnderground Piping.

(2) ASCE Publication Saismic R6sponse of Buried Pipes and Structura!

Components Report by the Seismic Analysis Committee of the ASCE Nuclear i Structures and Materials Committee.

l 2. CE will har not yet determined if the SSAR should be revised to proside l

more definition of analys.s methods to be used for c. valuating the effects of extsrnal evear.s such as wind, tornados, and missiles. At present, the rules for ASME III Class 2 or 3 piping apply for loads from external events the same as Tey do for seismic and other dynamic arid static _ loads. If CE determines additional information in the SAR is needed to define magnitude of loads from sxcernsi events or define Service Limit stress values for these events, the SAR will be revised.

ABWR PIPING DESIGN CRITERIA AND SANPLE ANALYS!$

March 23-27, 1992 Item No.: A27 By:

6 DESCRIPTION OF CONCERN:

Hydrodynamic building filtered loads are based on the Japanese K6/K7 plant design and soil conditions provide justification for applicability of those loads to the ABWR considering the variation in soil properties and their effects on the building response.

RESPONSE BY GE:

Based on past BWR plant experience, the trend indicates that the floor response spectra (FRS) increases as the foundation soil becomes softer. Since K6/K7 is a soft-soil site, the rasulting FRS for hydrodynamic loads are considered applicable for other site conditions and can be used for the-standardized-design.

STAFF EVALUATION:

CONCLUSION:

e a

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J ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSIS March 23 27, 1992 Item No.: A28 By: l DESCRIPTION OF CONCERN:

a) Provide additional information to justify the feedwater thermal i stratification load definition. Identify test programs and plant measurements I which support the model, b) Justify the application of a linear temperature profil? (versus a hot to cold step change) on the pipe cross-section.

c) Thermal striping is not considered in the analysis. Provide evidence to )

support neglecting the thermal striping phenomenon in the fatigue analysis.

RESPONSE BY GE:

a) Test programs and plant measurements were obtained at the following plants:

Leibstadt, Hanford Unit 2 and Nine Mile Point Unit 2. Additionally, an extensive finite element analysis of ths Shoreham feedwater piping system was performed to obtain a better understanding of thermal stratification. See also the Response to item No. A17.

b) Using a hot to cold step change at th:. center of the pipe will be overly conservative. The reasons are given below:

1. The analysis assumes the same thermal stratification for the entire length of horizontal pipe, but thermal mi::ing occurs along the pipe due to flow which would reduce the stratification.

2. A step change at the center creates the maximum bending moment. In the actual flow, the hot and cold fluid does not have a step change due to axial flow.

3. The probability for the change from hot to cold fluid occurring at the center of the pipe is small since the amount of flow required for stratification is less than 3% flow. If the dividing line is not at

, the center, then the bending moment due to stratification is reduced.

l l

c) Temperature stratification between the top and bottom of the feedwater piping and nozzles has caused pipe bowing with pipe support damage and flange leakage, but no pipe failures. The temperature stratifications which have been measured have shown that stratification occurs for only short time durations following reactor scram as the hot pi)ing is filled with cold water, and again during startups as feedwater heating segins, filling the cold piping with hot water. So far, operation of BWR feedwater pi)ing systems have avoided fatigue failure due to prolonged operation wit 1 a fluctuating cold

water-hot water interface, due to the fact that feedwater velocities are high enough to maintain the piping at constant temperature throughout during most of its operating time.

STAFF EVALVATION:

CONCLUSION:

9 NRC Audit of GE on ABWR P! PING DESIGN CRITERIA AND SAMPLE ANALYSES March 23 27, 1992 Item No.: B1 By: S.J. Lin DESCRIPTION OF CONCERN:

Currently a criteria document for the determination of break locations and dynamic effects associated with the postulated rupture of piping for the ABWR does not exist. GE should create such a document, b

RESPONSE BY GE:

GE will incorporate the current SRP 3.6.2 criteria and postulated locations in the SAR. A separate criteria document is not required for determination of break locations.

7 STAFF EVALUATION:

CONCLUSION:

l

i NRC Audit of GE on ASWR PIPING DESIGN CRITERIA AND SANPLE ANALYSES March 23-27, 1992 Item No.: 82 By: S.J. Lij DESCRIPTION OF CONCERN:

The sample analysis of the effects of high energy line braaks in the main steam line was not complete at the time of the audit. Complete the analysis for NRC review. 'The analysis should be in accordance with revi'ed Section 3.6.2.2 of the SAR.

RESPONSE BY,GE:

Sample analyses of main steam line A with two typical break locations have been studied. The first location is at the safe end nozzle break and the second location is at the break of sweepolet to the inlet SRV A.

Both breaks have been restrained by the-pipe whip; restraints and by the ,

pipe stopper (bumper). Assessment of the penetration loads will be

, submitted in the final report. It is evaluated based on the current SRP 3.6.2 criteria.

STAFF EVALUATION:

LONCLUSION:

i NRC Audit of GE on ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSES March 23-27, 1992 Item No.: 83 By: S.J. Lin DESCRIPTION OF CONCERN:

The procedures and criteria specified in Section 3.6.2.2 of the SAR relating to analytic methods to define blowdown forcing functions and response models for postulated ruptures of piping are inconsistent with procedures and criteria to be used for the ABWR plant as described during the audit. Revise Section 3.6.2.2 of Un Su' to be consistent with current SRP 3.6.2 requirements and curreat G7 <rocedure and criteria.

RESPONSE BY GE:

Blowdown forcing functions are determined by the method spe-ified in Appendix B of ANSI /ANS-58.2-1988.

In addition, the forcing functions due to the postulated pipe breaks near the reactor or the oranch connection is calculated by the solution of one-dimensional, compressible unsteady steam flow in the gas system.

The numerical analysis is performed by the method of characteristics.

The flow starts with steady flow from RPV to turbine. A pipe break boundary conditon is applied at the break location for the pipe to reverse its flow direction. The pipe segment force time histories are calculated by the momentuo change in the pipe segments of a close system. The broken pipe segment force time history is calculated by ANSI /ANS-58.2-1988.  ;

i The pipe displacement due to blowdown reaction load is modeled and D

analyzed using computation program available in the market, i.e. ANSYS.

The stresses at the penetration and at other location will be able to analyze by the nonlinear program. The-pipe whip restraint capacity is determined by the GE U-rod design and PDA program for selection.

STAFF EVALUATION:

e CONCLUSION:

. _ ._ _ _ . _ - _ _ _ _ __ _ ._ _ _ . _ . _ _ . - _ . _ ~

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. , _ NRC Audit of GE on ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALY9ES March 23-27, 1992

! 64

Item No.: 24 By: I

l

DESCRIPHON OFCONCERN

4

. In Section 3E.2.1 of the SSAR, GE proposed the use of a modified l J Integral and associated modified tearing modulus for beyond

J-controlled crack growth characterization. Justify the proposed j Jmod-Tmod characterization.

4 1

i RFRPONSE BY GE:

i Section 3E.2.1 is . revised to identify the approach as an illustrative i one which, if adopted, should be justified based on its acceptability i by the technical literature. A Jo-approach is identified as a potential-more justifiable approach.

l l

j STAFF EVALUATION:

I I

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i 4

l

l NRC Audit of GE on L ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSES March 23 27, 1992 l - 6C '

j ltem No.: 25 By: j i i i DESCRIPTION OF CONCERN:

l Section 3E.2.23 describes the carbon steel fracture toughness test l program. GE should indicate that _the extent of the program _ indicated in Table 3E.2-4 may not _be repesentative for the actual test program j required for approval of an application of LBB qualification of selected piping systems.

t RFRPONSE BY GE:

j The following is added at the end of the paragraph leading into l Section 3E.2.21. "The purpose of the test program is to generate the

{ necessary data for -application in Section 3E.6 and to illustrate a

general procedure of conducting the tests per requirements of

Item (10) in Section 3E.1.2. The extent of the test program for NRC's

approval of an application will depend upon the i,,entified

~

re q uire m e n ts."

STA57 EVALUATION:

i 4

4 i

CONCLUSION:

L

2 .-

i 4

l s

NRC Audit of GE on j ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSES

. h1 arch 23 27, 1992 i  %

i item No.: 26 By:

i l DESCRIPTION OF CONCERN; Section 3.6.3 of the SSAR does not contain procedures 'and criteria for LBB evaluations of bimetallic welds. Provide these procedures and criteria.

l l

RESPONSE BY GE:

i Section 3E.3.4 is added to address the bimetallic welds of austenitic

! steel to ferritic steel as follows: "For joining austenitic steel to ferritic i steel, the Ni Cr-Fe Alloys 82 or 182 are generally used for weld

metals. The procedures recommended in Section 3E.3.3 for the

!- ~austenitic welds are applicable to these weld,ny,,tals. This is justified L based on the commonalisy edente procedures, for' flaw . acceptance in i the ASME Code Section XI,:- Article IWB-3600 and Appendix C, for.

both types of the welds. If other types of bimetallic weld metals are used, proper procedures should be used with generally acceptable justification."

STAFF EVALUATION:

\

l .

l CONCLUSION:

1

NRC Audit of GE on ABWR PIPING DESIGN CRITERIA AND SAMPLE ANAi YSES Mareh ' 23-27, 1992 67 Item No.: 27 By:

DESCRIPTION OFCONCERN:

In Section 3E.3.1.3 of the SSAR, GE Proposed a linear interaction criterion for tearing instability evaluations for combinations of applied tension and bending stresses. Justify the proposed . criterion.

RFSPONSE BY GE:

The second paragraph of Section 3E.3.1.3 is expanded as follows: "The applicabilty of this proposed rule should be justified by providit.g a comparison of the predictions 'by the proposed approach (or _ an alternate . approach) with those available for cases where the combination is treated together."

STAFF EVALUATION:

CONCL1]S10N:

NRC Audit of GE on -

ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSES March 23-27, 1992 Item No.: 28 By:

DESCRPTION OF CONCERN:

In Section 3E.4 of the SSAR, GE proposed a procedure for estimation of leak rates during _ blowdown of saturated steam. Justify the proposed procedure.

RESPONSE BY GE:

The following is added to the fourth paragraph of Section 3E.4.1.1 after the first lead-in sentence: "However, a justification should be provided by comparing the predictions of the proposed method with the available experimental data, or a generally acceptable method, if available, should be used."

STAFF EVALUATION:

CONCLUSION: ' -

4

w .-

NRC Audit of GE on ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALYSES March 23 27, 1992 89 Ite m N o.: _ 32 By:

DESCRIPTION OF CONCERN:

Clarify the Gudas data in Figure 3E.2 8 of the SSAR.

RESPONSE BY Cd; The Gudas data in Figure 3E.2 8 are for carbon steel SA106 Gr. B base metal (with L C orientation). A clarification is included on the figure.

STAFF EVALUATION:

CONCLUSION:

I #

ABWR nem y aa=

[tandard Plant 43 p.mse ma

~"

displacement),

treatment which refines the grain structure and,

,._, (2) a charpy test at .50* F with a specified I ao .a arc the initial and current crack minimum absorbed energy of 13 ft.lbs.

lengths respectnely.

The electrodes and filter metal requirements I For the particular case of the compact tension for welding carbon steel to carbon or low alloy spectmen geometry, the preceding Equation and the steel are as specified la Table 3E.21. A c:rresponi:g rate taic the form comprehensive test program was undertaken to characterize the carbon steel base and weld ,

a material toughness propertist. The nem section Jmod describes the scope and the results of this l

• 1 * [a 7 .J,p1,, .da (E.2-4) program. '

o 3 where Jp g is the nonlinear part of the 3E.2.2.1 Fraccare Toughness Test Proysa deformation theory J, b is the remaiu;ss ligassat and 7 is The test program consisted of generating true stress true straia curves, J. Resistance curves j 7 =

(1 +0.76 b/W) (E.2 5) and the charpy V.sotch tests. ~wo materials were selected : (1) SA333 Gr. 6,16 inch Consequently the modified material tearing diameter Schedule 80 pipe and (2) SA516, Gr. 70, modulus Teod can be defined as: 11/4 inch thickness plate. Table 3E.2 2 shows the chemical composition and mechaascal property Teod . Tmat + F. s .Jpl test information provided by the material ag8 b (E.24) supplier. The materials were purchased to the same specifications as those to be used is the Since in most of the test J.R curves the ASWR applicatiets.

o10 limit was violated, all of the material J.T data were recalculated in the Jood, Teod To produce a circumferential butt weld, the format. The Jmod Teod calculations were pipe was cut la two pieces along a performed up to crack estension of Aa=10% of circumferential plans and welded back using the the original ligament is the test specimes. The shielded sistal arc process. The weld prep was J.T curves were then satrapolated to larger J of single V design with a backing ring. The values using the method recommended in N1JREG prehzat temperstars was 200*F.

1061. Vol. 3 (9].

+ The plate material was cut along the 3E.2.2 Carbon Steels and Aseadat=I longitadiaal adn and welded back ming the SAW Welds proceas. The weld prey was of a single V type s with one side as wortical and the other side at The carbon steels used la the ABWR reactor 45'. A backing plate was used during the coolant pressure boundary piping are: SA 106 Gr welding with a clearance of 1/4 inch at the j B. SA 333 Gr. 6 and SA 472. Gr. C70. The first bottom of the V. The y temperature was

[ specification covers seamleen pipe and the second maintained at less than 500 F.

one pertains to both seamless and seam welded -

pipe. The last one portains to seam. welded pipe Both the plate and the pipe welds were for which plate stock is specified as SA 516. Gr. X rayed assording to Code (11] requirements and

70. The correspondlag material specifications were foemd to be satisfactory.

""/for carbos steel flanges, fittlags and forgings are(.ge=es by 2.y..... It is well.known that carbos steel base

..p.,.i.., , . . t . r.h; . py% aj 4n < *P' materials show cor.aerable saisotropy in While the chemical composities requiressats fracture toughtess properties. The toughness for a pipe per SA 106 Gr. B and SA 333 Gr. 6 are depends on the orisatation and direction of identical, the latter is subjected to two propagation of the crack la relation to the additional requirernents:(1) a normalizing heat principal direction of mechanical working or m .a

, ,. z.n.,

g., '

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H " *- w w al'hea 4 5 ,.7 3,4. a %.s .s . a s k.e.a b e. *^9M * 'a A . , , , ,,. . ,

!>$

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f l 3E.3.3 Modified Limit lead Methodology for Austenitic Stainless Steel Piping Reference 16 describes a modified limit load methodology that may be usec to calculate the critical flaw lengths and instability loads for austenitic l stainless steel piping and associated welds. If appropriate, this or an j equivalent methodology may be used in lieu of the (J/T) mothedology described in 3E.3.1.

1 36,3.4 Me

• w. a.i, hr B ~ t + *llic WelJa

^S0%F Sg . _ ,e. a 5

. ss. t s a6m, kf 7G i.

Q .$.J.c o' ~

s l

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1

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standard Pf ant u rst m erv g

! the J.istegral for a pipe with a through wall This upea ls addrused ness.

circumferentia1Aw subjected to pure tension or i pure bending are as follows JEJ.1J Tearing Instability Evaluatlee l Considertag Bosh the Membrose and Beedjag l Insig '

Stressee (3E.3 6)

E' * -

4 J = ft (a , tE) E n+1 Based on the estimation scheme formulas and the tearing instability methodology just

, a 's 8 e c (2) hg (b3,n,E)'E outlined, the instability bending and tension b t ,Po , stresses can be calculated for various j through. wall circumferential flaw lengths.

where, Figure 3E,3 2 shows a schematic plot of the instability stresses as a function of flaw l, f t(a, n, E) , a F2 a, n,1) length. For the same stress level, the t

! b t allowable flaw length -for the bending is

! *

• R' 18 expected to be larger than the tension case.

i Po = 2 'o Rt (r . 7 2 are sia When the applied stress is a combinuion of

! (1 sia, y) } the tension and bending, a linear interaction

2 rule is used to determine the instability stress C or conversely the critical flaw length. The *T ggggas application of linear interaction rule is g,

' (3E.3 7) certainly conservative when the instability load ,

J = ft (a,, E) M' . is close to the !!ait load. , -- ' , ,

t E a+1

. a 'o 8 e c (3) h ta, i b n, E) M The interaction formulas are followieg: (Sec j b t ,M e, Figure 3E.3 2) l .

, where, Critical Flaw banth (3EJ 5) 4 f t(3. n.E) . ra (E)* F' b t I a=(8 e , t,, ) ae ,g + ( '1) ac.t

't+#b *t+3b (a, n, E) l b t .ger,.

l M = applied ass.brane stress e = Mo (cos(p f sin (7)) 't

'b = m *sd bendia. = .sa The sendimensional fn=ceia== F and h are gives i la Refersaca 6 ae,g = critical flaw length for a tecsion stress of ('t +'b)

While the calculation of J for gives e, s. .

'o and load type is reasonably straight. a,b c = critical flaw length for a bending forward, ore isses that aseda to be addrenad is stress of ('t+'b) the tearing instability evaluation when the loading includes both the membrane and the Instabdirv aanding strena tending stresses. The estimation scheme is , (3E.3 9a) capable of evaluating only one type of stresa at Sb = (1 . ft) ,e a time. 't b I

_i nu.:

, _ - . - - . -- . - . . . . - . ~- . - . .. .. .. . .-

7F l

! M nAstonAE i Standard Plant m4 3E.4 LEAK RKE CALCULATION For givea stagnation conditions and crack e

j 5!ETHODS geometries, the leak rate and exit pressure are

! calculated using as iterative search for the Leak rates of high pressure fluids through exit pressure starting from the saturation l cracks in pipes are a comples function of crack pressure corresponding to the upstream i

geometry, crack surface roughness, applied temperatura and allowing for friction.

l stresses, and inlet fluid thermodynamic state. gravitational, acceleration and area change l Analytical predictions of leak rates essentially pressure drops.. The inertial flow calculation j consist of two separate tasks: calculation of the is performed when the critical pressure is -

! crack opening area, and the estimation of the lowered to the back pressure without finding a &

! fluid flow rate per unit area. The first task solution for the critical mass fluz. bl

requires the fracture mechanics evaluations based  ;

! on the piping system stress state. The srcond A conservative methodology was eveloped to i task involves the fluid mechanics considerations handle the flow of t=to. phase, mixture or i in addition to the track geometry and its surface superheated steam through a crack.uTo make the roughness information. Each of these tasks are model costituous, a correction factor was i now discussed separately considering the type of applied to adjust the mass flow rate of a fluid state in BWR piping, saturated misture to be squal to that of a slightly subcooleri liquid. - Similarly..a 3E.4.1 Leak Rate Estirnation for correction factor was developed to ensure Pipes Carrying Water consiauicy as the steam became superheated. The l

o y ba. superheated medet was developed by applying EPRt. developed computer code PICEP [1]per thermodynamic principles to as isentropic

, used in the leak rate calculations. The basis expansion of the single phase steam.

for this code and comparison of its leak rate i predictions with the experimental data is The code can calculate flow rates through

{ described in References 2 and 3. This code wee fatigue or IGSCC cracks and has been verified

1. h m::'y used in the successful application against data from both types. The crack surface of LBB to primary piping system of a PWR. The roughness and the number of bends account for basis for flow rate and crack opening area the differsace is geometry of the two types of j

calculations in PICEP is briefly described cracks. The saideline for predicting leak rates first. A comparison with experimental data is ' through IGSCCs when using this model was based shows next.- os obtaining the number of turas that give the A best agreement for Bjttelle Phase 11 test data l 3Etl.1 Descripties et Basis for flew Rate of Collier et al. [M.7 For fatigue eracks. it Calculasses is asaamed that the crack path has no beads.

T1:e ther@ model impisamentsd la P!CEP 3E.4.1J Bands ser Creek Opening Area compuer program assames the leakass Sour through - rsand.d-pipe cracks to be issathalpic and homogeneous, but it accoasta for ans egailibriam

• flashing

• The crack openias area in FICEP code is

transfer process between the liquid and vapor calcalated mains the estimation scheme

, phases. formalas. The plastle contribution to the i displacent is competed by summing the Fluid friction due to sarface roaghness of the contribations of bending and tension alone, a '

- v: alls and carved flow paths has been incorporated proceders thas anderestimates the displacent in the model Flows through both parallel and from combined anasion and bendias.- However, the convergest cracks can be treated. Due to the plastic contribation-is expceted to be complicated geometry within the flow path. the insignificant because the applied stresses at model uses some approximationis and empirical normal operaties are generally such that they do factors which we're confirmed by comparison act produce significant pissticity at the l against test datt cr acke d. location.

? Other methods (e.g..' Reference 4) may be ured for leak rate estimati0n at the descretion of the applicant.

Amemenses t 3F.41

7I ABWR standard Plant

zuix4m erv 4 5000 m_

l

. (5 A I og , 4, . 3 , -S . a. M e >.t, LC Or:e v. . . )

g uCASDATA 9 CARBON STEEL WELO CATA 4000 A

A l A

- A 6

9 A 3000 A

i . A 4 -

d

• I A

m0 -

A A

1000 g LOW 8R SOUNC MATERIAL J.T CURVE FOR CARBON STREL AT 550*P I I I I I i  !

O 100 200 300 400 500 W 700 TEARING MODULUS. Y s7 597 54 iI figure 3E.2 8 PLOT OF 550* F J,g, T,,, DATA FROM TEST J-R CURVE n:-r

., ; NRC Audit of GE on ABWR PIPING DESIGN CRITERIA AND SAMPLE ANALyg33 March 23-27,1992 Item No.: bD By:

DESCRIPTION OF CONCERN:

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. . _ RESPONSE BY GE: _

% inansistendes In the SsAR wi/I be wecfea.t 4

STAFF EVAIDATIpMt CONCIDSION:

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