ML18037A083

Elastic-Plastic Fracture Mechanics Assessment of Nine Mile Point Unit 1 Beltline Plates for Svc Level a & B Loadings

ML18037A083
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Site:	Nine Mile Point
Issue date:	12/16/1992
From:	Michelle Manahan MPM RESEARCH & CONSULTING
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ML17056C176	List: ML17056C175 ML18037A083
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MPM-USE-129215, NUDOCS 9212220267
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NMPC Project 03-9425 MPM-USE-129215 FINALREPORT entitled ELASTIC-PLASTIC FRACTURE MECHANICS ASSESSMENT OF MjMEMILEPOINT UNIT 1 BELTLINEPLATES FOR SERVICE LEVELA AND B LOADINGS vrv"ad+ )vydvgs&vd' vrd~@Vdrvrvd drdv CV yr.ddv VrV~~PrdV rrd V

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NMPC Project 03-9425 MPM-USE-129215 FINALREPORT entitled ELASTIC-PLASTICFRACTURE MECHANICS ASSESSMENT OF NINE MILEPOINT UNIT 1 BELTLINEPLATES FOR SERVICE LEVELA AND B LOADINGS MPM Research cf CmrsuICi'ng 8~+~:

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~ 8BFVAO CRAVE HBB7S mrceur mv~ ~our December 16, 1992 Prepared by Dr..Michael P. Manahan, Sr.

MPM Research & Consulting 915 Pike Street Lemont, PA 16851-0840 Prepared for Niagara Mohawk Power Corporation 300 Erie Boulevard West Syracuse, NY 13202

Table of Contents 1.0 NMP-1 Low Use Issue 1.1 Weld Metal Screening Criterion Calculations 1.2 Base Metal Screening Criterion Calculations 1 ~3 Summary o

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2.0 Approach to Resolution...........................

12 3.0 Analytical Model for Service Level A and B Analysis..........

13 4.0 4.3 4.4 Material Models 4.1 Technical Basis for Use of A302B J-R Curve 4.1.1 Material Composition Analysis.....

4.1.2 A302B Ductile Fracture Behavior...

4.2 A302B J-R Curve Model..............

4 2 1 JIc USE Correlation 4.2.2 J-R Curve Determination........

A533B J-R Curve Model...

Material Parameters for Elastic-Plastic Fracture Mechanics Analysis 4.4.1 Young's Modulus..............

4.4,2 Poisson's Ratio.........,,.....

4.4.3 Yield Stress..

Model =i

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14 14 14 15 15 16 17 18 19 19 20 20 5,0 Elastic-Plastic Fracture Mechanics Assessment 5.1 Model Description...............

5.2 Calculations for A302B Material Model 5.2.1 Plate G-8-1 Analysis........

5.2.2 Plate G-307-4 Analysis......

5.3 Calculations for A533B Material Model 5.3.1 Plate G-8-1 Analysis........

5.3.2 Plate G-307-4 Analysis......

5.4 Summary of Conditions Analyzed....

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44 44 44 44 45 45 45 45 6.0 Summary and Conclusions...........,...............

71 7.0 References 74

1.0 NMP-1 Low Use Issue Testing and evaluation must be conducted to ensure that nuclear reactor pressure vessels are safe in terms of both brittle and ductile &acture under normal operation and during design basis transients.

With regard to ductile fracture protection, Appendix G to 10 CFR 50 prescribes a

screening criterion of 50 ft-lbs. Ifany beltline materials are expected to exhibit Charpy Upper Shelf Energy (USE) P-L orientation) below 50 ft-lbs, then additional analyses must be performed to ensure continued safe operation, The Draft ASME Appendix X [ASME92] was developed to assist licensees in performing elastic-plastic fracture mechanics evaluations for beltline materials with low upper shelf energies.

This report documents application of the draft Appendix X calculative procedures to two Nine Mile Point Unit 1 (NMP-1) beltline plates.

The NMP-1 beltline materials were evaluated to determine whether any materials would exceed the 50 ft-lb screening criterion, The results of these evaluations are shown in Tables 1-1 and 1-2, and were presented in the response to NRC Generic Letter 92-01 [MA92]. With the exception of plate G-8-3, only L-T Charpy data are available for the beltline plates.

Therefore, it is necessary to apply an L-T to T-L conversion factor to obtain T-L orientation properties for the plates.

Since the weld metal is essentially isotropic, orientation considerations are not important for the beltline welds, The data in Table 1-1 were developed using the Regulatory Guide 1.99 (Revision 2) [RG1.99]

(RG1.99(2)) generic model.

The data in Table 1-2 were developed using the RG1.99(2) procedure with plant-specific data.

As shown in Table 1-2, the plant-specific model shows that none of the beltline materials are expected to fall below 50 ft-lbs prior to end-of-license (EOL).

It is Niagara Mohawk Power Corporation's (NMPC's) position that the plant-specific model is appropriate.

However, since two of the beltline plates are expected to approach the screening criterion, NMPC has committed to perform an elastic-plastic fracture mechanics assessment.

Further details concerning the screening criterion calculations are provided in Subsections 1.1 and 1.2 below.

1.1 Weld Metal Screening Criterion Calculations Full Charpy curves for the NMP-1 beltline welds were not measured at the time when the vessel was fabricated.

However, Charpy data at 10'F were measured by Combustion Engineering and these data are summarized in References

[MA90] and [MA91]. An innovative methodology [MA85]was developed to determine the initial RT~ for cases where the data required by the ASME Code are not available. This approach was applied to the NMP-1 beltline materials and the results are described in Reference [MA90]. The methodology for RT~ determination includes estimation of the unirradiated USE in cases where full Charpy curves are not available.

Weld W5214/SG13F is the surveillance capsule weld. This weld was not made using the same wire heat or flux lot as the beltline welds.

However, the weld materials were manufactured by the same suppliers, the weld wire type and flux type are the same

R (RACO 03 wire, Arcos B5 flux), the same procedure was used, and the Cu and Ni content is representative of the beltline weld 1248/4M2F

[CE90, MA91]. It has been assumed that the capsule weld material is similar to the beltline welds in terms of its mechanical behavior response.

The irradiated Charpy data for the capsule weld material was analyzed using the SAM McFRAC code [McFRAC]. This code is based on a non-linear, least squares, regression analysis using the Weibull statistic.

The Weibull statistic has been shown to be the correct statistic for analysis of fracture data by considering the microstructural mechanisms involved in the &acture of ferritic, pressure vessel steels [MA85a].

The confidence bands are measures of 'the goodness of fit'nd do not indicate the engineering 95% statistical error spread.

This uncertainty must be analyzed using conventional statistical methods.

However, the McFRAC confidence intervals are used to measure confidence in the fitof a particular data set as well as the inherent scatter due to the fracture process.

These error bands must be calculated, particularly for sparse data sets, because in many cases the ability to fit sparse data drives the uncertainty.

The McFRAC analysis for the irradiated capsule weld is shown in Figure 1-1.

The procedure used to calculate the RTN of the NMP-1 beltline welds requires estimation of the unirradiated USE.

Odette's yield strength model [OD86] was used to estimate the surveillance weld unirradiated USE using the irradiated USE as input.

In particular, USE' UEEIRR

where, f = &actional change in USE f

9 0 x 10 hviI + 0 02 (haiI 40) b,o= change in yield strength due to irradiation USE' unirradiated USE USE~ = irradiated USE The irradiated USE was measured at 7.98 EFPY and found to be 110 ft-lbs.

Using Odette's model and the measured yield strength change, the unirradiated USE for the surveillance weld is estimated to be 128 ft-lbs.

Another important aspect of the RTNDY evaluation, which was used in the beltline weld USE evaluation, is the estimation of the confidence interval for energy measurement (2@a) at the 50 ft-lb level.

The 2oa for the surveillance weld at the 50 ft-lb level was estimated at 13.5 ft-lbs. This estimate is consistent with the uncertainty in determination

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of the USE for tests conducted on the upper shelf.

The minimum unirradiated USE data for the beltline welds shown in Table 1-1 was determined assuming that the Charpy behavior of the surveillance weld is similar to the response for the beltline welds.

To ensure conservatism, the measured irradiated USE was used as an estimate of the unirradiated USE.

The measured irradiated USE for the surveillance weld (110 ft-lbs) was then reduced by 2'13.5 ft-lbs) plus an additional 6.5 ft-lb for conservatism.

This lower bound estimate of 90 ft-lbs was conservatively assumed to represent the unirradiated USE of the beltline welds.

In response to the NRC's request, additional analyses are being performed to more accurately characterize the uncertainty in the RTN and USE estimation procedure, and the results of these analyses willbe reported to the NRC in the near future under separate cover.

1.2 Base Metal Screening Criterion Calculations In order to identify the beltline plates which may potentially fall below the 50 ft-lb screening criterion, the guidance in paragraph C.1.2 of RG1.99(2) was followed. Since only L-T orientation data are available for most of the beltline materials, the Reference

[MTEB81] guidance was used to convert from the L-T to T-L orientation.

In particular, the L-Tvalues were multiplied by 0.65 to obtain the T-Lorientation estimates.

As shown in Table 1-1, based on these conservative

models, plates G-307-4 and G-8-1 were identified as the beltline materials which may exceed the screening criterion.

Plate G-307-4 is also the critical plate material from an ARTNDT perspective.

Based on the results of the RG1.99(2) generic model analysis, further calculations were performed for plates G-8-1 and G-307-4 on a plant-specific basis.

Examination of the irradiated upper shelf data presented in Reference [MA91] suggests that the shelf drop is negligible.

However, this conclusion is tentative for plate G-8-3 since there are not sufficient USE data available for statistical analysis.

Capsule B is scheduled for withdrawal during the 1996 outage.

This capsule can provide the data needed for verification of a small upper shelf energy decrease for both the G-8-1 and G-8-3 materials.

In the case of plate G-8-1, there are three irradiated and three unirradiated USE points available for analysis.

These data are summarized in Table 1-3. Comparison of the linear averages suggests that the 8 USE is so small that itis within the measurement uncertainty.

Ifthe hUSE is conservatively calculated using the mean of the unirradiated data and the lowest irradiated data point, the hUSE is 10%. Similarly, ifthe bUSE is calculated using the lowest irradiated and unirradiated points, the d,USE is 5%.

The G-8-1 Cu content (0.23 Wt. %) is close to the G-307-4 Cu content (0.27 Wt. %). Therefore, a chemistry correction was not applied.

The Reference [MTEB81] L-T to T-L conversion factor of 0.65 appears to be overly conservative for the NMP-1 beltline plates.

In particular, the measured L-T to T-L conversion is 0.82 [MA91].

Applying these material-specific factors, the best estimate USE data for plates G-8-1 and G-307-4 are given in Table 1-2,

The b,USE estimates in Table 1-2 were obtained using the guidance of paragraph 2.2 of Regulatory Guide 1.99 (Rev. 2) with an I T to T-L conversion factor of.8 and an assumed dUSE of 10% at 7.98 EFPY.

The L-T to T-L conversion factor of 0.8 was obtained using the plate G-8-3 lowest measured USE data measured in both the L-T and T-L orientations.

Based on this analysis, it is predicted that the critical plate USE will not fall below 50 ft-lb prior to EOL. It is recognized that additional data and analyses willbe needed to confirm the plant-specific calculations.

The on-going NMPC work to develop material-specific models is described in Section 2.0.

1.3 Summary In summary, NMPC believes that the models used to calculate the Table 1-1 data are overly conservative for the NMP-1 beltline materials and the plant-specific analysis is representative of the actual plate material condition. Microstructural data obtained to date indicates a large population of MnS inclusions, MO,C precipitates, and Fe,C precipitates in the unirradiated plate [FR92].

These precipitates and inclusions have been shown to be stable under irradiation. It has been proposed [MA91b] that the lowering of the upper shelf due to neutron damage in steels with initially high concentrations of particles is expected to be negligible since the irradiation induced defects (Cu rich precipitates, microvoids) willnot significantly influence the fracture process on the upper shelf.

As discussed earlier, the Reference [MA91]data support this proposition. Accordingly, it is inappropriate to apply generic correlations, developed using data for low sulfur steels (A533B), to predict the AUSE for the NMP-1 plate materials.

Therefore, as described in Section 2.0, NMPC is developing material-specific models, which accurately model the physics of ductile fracture, which willyield accurate and conservative predictions of the effects of neutron damage on ductile fracture properties.

Additional work is also underway to provide statistical justification of the 0.8 L-T to T-L factor.

In the

meantime, an elastic-plastic fracture mechanics assessment has been conducted to demonstrate that there is sufficient margin to ensure continued safe operation of NMP-1.

Table 1-1 Estimated Upper Shelf, Energy for NMP-1 Beltline Materials [MA92]

Materiai Plates Wt.

o/'u Minimum Unirrad.

USE (ft-Ib)

L-T

'inimum Unirrad.

USE (ft-Ib)

T-L'rradiation Decrement USE (%)

12/16/91 Irradiation Decrement DUSE (%)

EOL(25 efpy)'redicted USE (T-L)'2/1 6/91 (ft-Ib)

Predicted USE(T-L)'t EOL(25 efpy)'ft-Ib) 6-8-3/6-8-4 0.18 G-8-1 0.23

. G-307-3 0.20 6-307-4 0.27 6-307-10 0.22 78 82 100 80 97 64 /507 53.3 65.0'2.0'3.1 15 17 16 20 17 17 20 19 23 20 54.4 44.2 54.6 41.6 52.4 53.1 42.6 52.7 40.0 50.5 Welds W5214/5G13F 0.1 8 86054 B/4E5F 0.22 1248/4K1 3F 0.22 1248/4M2F 0.22 100 904 904 904 17 20 20 20 20 23 23 23 83.0 72.0 72.0 72.0 80.0 69.3 69.3 69.3

'he L-T and T-L designations apply to plate material only

'easured using archive plate in the T-L orientation

'rradiated value measured at a fluence of 4.78 x 10" n/cm' Conservatively estimated using data in [MA90]and [MA91]

'ast fluence of 7.26 x 10" n/cm't the peak 1/4T position

'ast fluence of 1 44 x 10te n/cm'at the peak1/4T position

'ata from Reference [CE90]

'. Surveillance Weld

'alculated by multiplying L-T data by 0.65

Table 1-2 Best Estimate Upper Shelf Energy for Plates G-8-1 and G-307-4 G-8-1 G-307-4 Minimum Unirrad.

USE (ft-lb)

L-T 82 80 Minimum Unirrad.

USE (ft-lb)

T-U 65.6 64.0 Irrad.

Decre-ment BUSE(%)

12/16/91 Irrad.

Decre-ment b,USE(%)

EOL (25EFPY) 13 13 Predicted USE (T-L) 12/16/91 (ft-lb)~

58.4 56,9 Predicted USE (T-L) at EOL (25EFPY)4 (ft-lb) 57.1 55,7

'late G-8-3 measured L-T to T-L conversion of 0.8 applied

'ast fluence of 7.26 x 10" n/cm't the peak 1/4T position

'aragraph 2.2 of RG1.99 (Rev. 2) used.

bUSE conservatively calculated using average unirradiated data and lowest irradiated datum

'ast fluence of 1.44 x 10" n/cm't the peak 1/4T position

Table 1-3 USE Data for Plate G-8-1 Unirradiated USE (ft-Ib)

Irradiated'SE (ft-Ib)

Measured data Measured data Measured data 82 83 95 78 99 104 Average of Measured Data Shift based on Lowest Measured Data Shift Conservatively Based on Mean Unirradiated and Lowest Irradiated Data 86.7 82 86.7 93.6 78 78

'hift is negligible and within experimental scatter

'rradiated to a fast fluence of 4.78 x 10" n/cm'0

CQ 125 I

IiL

'f 00 Q

75

/

4 j

a I

4 k

gk

$ g Jg Jl gg JX 300 TEST TEMPERATURE (F)

NINE MILE POINT UNIT 1

WELD 521 4/5G1 3F (SURVEILLANCE WELD) 150 IRRADIATED DATA WEIBULL FIT TRANSITION WEIBULL FIT UPPER SHELF HYPERBOLIC TANGENT FIT CONFIDENCE LIMn'95+)

CONFIDENCE LIMIT (95+)

CONFIDENCE LIMIT (85%)

CONFIDENCE LIMIT (95+)

UNIRRADIATED DATA UNIRRADIATED CHARPY CURVE Figure 1-1 Charpy Impact Energy Versus Test Temperature for Irradiated Weld Specimens from the Nine Mile Point Unit 1 300 Degree Capsule 11

2.0 Approach to Resolution NMPC is currently performing an ASME draft Appendix X (Revision 11) analysis to resolve the low USE issue.

This report demonstrates that for the Service Level A and B loadings, the NMP-1 USE levels willnot go below the minimum safe USE level based on the Appendix X analysis.

This conclusion is valid regardless of whether the generic model (Table 1-1) or the plant-specific model (Table 1-2) is used.

In addition to the elastic-plastic fracture mechanics assessment, the following elements of the NMPC Pressure Vessel Materials Integrity Research Program are expected to provide useful data for confirming margins of safety:

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L-T to T-L conversion modelling

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Upper Shelf Energy (USE) drop trend curve modelling

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Miniature specimen technology development

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Surveillance capsule reinsertion 12

3.0 Analytical Model for Service Level A and B Analysis Revision 11 to the Draft ASME Appendix X [ASME92], which is cuirently formulated as a Code Case, was applied to the NMP-1 G-8-1 and G-307-4 plates.

Interior axial and circumferential flaws, with depths of 1/4T and lengths equal to 6 times the depth, have been postulated.

Toughness properties, which correspond to the postulated flaw orientation, were used in the analysis: T-L orientation properties for circumferential flaws, and L-T orientation properties for axial flaws. Appendix X describes three permissible evaluation approaches for applying the flaw stability acceptance criteria according to the flaw stability rules: J-R curve - crack driving force diagram approach; failure assessment diagram approach; and the J-integral/tearing modulus approach.

The latter approach was used in the NMP-1 plate evaluations.

The following evaluation criteria, specified in Appendix X, were applied:

(1) Criterion for flaw growth of 0.1 inch Ji < Jp.i (2) Criterion for flaw stability

where, P'

1.25 P, J, =

applied J-integral for a safety factor on pressure of 1.15, and a 1.0 factor on thermal loading Jp i J-integral resistance at a ductile flaw growth of 0.1 inch P'

internal pressure at flaw instability P, =

accumulation pressure, but not exceeding 1.1 times design pressure Since J-R curve data are not available for A302M, analyses were performed using an A302B and an A533B material model.

The material properties used in the analysis are a conservative representation of the toughness and tensile properties of plates G-8-1 and G-307-4 at plant operating temperature.

Further details coricerning the material model are provided in Section 4.0.

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4.0 Material Models The NMP-1 beltline plates are A302B modified (A302M) steel. At the present time, sufficient J-R data are not available to construct an A302M model. The NRC has requested [TEL92] that the Appendix X calculations be performed using both an A302B and an A533B material model.

However, as discussed below, it is NMPC's position that the A302B model is the appropriate model for the NMP-1 beltline plates.

Justification for the use of the A302B model is provided below. However, both the A302B and A533B material models were analyzed in accordance with the NRC request.

Also, in accordance with the guidance provided in NRC letter [BR92], the lower bound J-R curves were calculated using the mean value for J, reduced by two standard deviations.

4.1 Technical Basis for Use of A302B J-R Curve Model 4.1.1 Material Composition Analysis The ASTM nominal plate chemistry requirements are compared with the NMP-1 measured plate chemistry data in Table 4-1.

The ASTM A302B steel was the steel used in construction of the older plants which are operating today.

Nickel was added to A302B to improve ductility, and this steel was designated A302M.

Eventually, the A533B standard emerged.

Examination ofTable 4-1 suggests that the NMP-1 plates would be accurately modelled by A533B J-R data.

However, the unirradiated USE levels for the NMP-1 plates are significantly lower than those of A533B materials.

Further, the sulfur (S) levels for the NMP-1 plates are higher than for the A533B materials used in the nuclear industry (Figure 4-1). As a result, the concentration ofmanganese-sulfide inclusions is expected to be higher in the NMP-1 plates than in the A533B plates. It has been suggested [MA91B]

that higher particle densities would be expected to lower the USE since they would act as delamination sites during the ductile fracture process.

Evidence for the detrimental effect of S on the USE level is shown in Figure 4-2.

As shown in Figure 4-2, the USE response for the NMP-1 plates is consistent with that of the A302B material which is substantially lower than that for A533B. Figures 4-3 and 4-4 suggests that the beneficial effects of Ni can be offset by high S levels.

As shown in Figure 4-4, A302M materials with low S content have USE levels consistent with those of A533B plates.

However, the A302B plates with S above the 0.02 wt% level have significantly reduced USE levels, In summary, the NMP-1 plates are expected to exhibit upper shelf fracture behavior which is representative of A302B steel from a material composition perspective.

This conclusion is based solely on Charpy USE data dependence on chemical composition.

As described below, the J-R data for A302B steel is more conservative than the J-R response of A533B steels.

The J-R data reported in [HI89] were used to construct the NMP-1 material model.

The composition of the NMP-1 plates, with the exception of Ni content, 14

compares well with the materials used in the [HI89] study as shown in Table 4-.2.

Also, the heat treatments and Charpy data for the NMP-1 plates compare well with the [HI89] heat treatments and Charpy data (Table 4-3).

Therefore, the fracture behavior of the [HI89] material is expected to be representative of the NMP-1 plates.

4.12 A302B Ductile Fracture Behavior Figure 4-5 illustrates the J-R curve specimen size dependence for reactor pressure vessel materials other than A302B.

Joyce [JOY91] concluded that deformation J-R curves which are developed beyond the J-controlled region can curve up, curve down, or stay consistent with J-controlled data. Joyce developed procedures for extrapolation of data beyond the low ha J-controlled region.

As shown in Figure 4-6, the extrapolated (small specimen) data agree well with the 2T CT data.

In contrast with the J-R curve data trends for other pressure vessel materials, Reference

[HI89] reported an unprecedented size effect for A302B steel.

As shown in Figure 4-7, the thicker the specimen, the lower the J-R response level after initiation. While similar data trends have been observed for some pressure vessel materials, decreases in the J-R curves of the magnitude reported by Hiser have not been reported earlier.

The micromechanical explanation for the J-R curve behavior shown in Figure 4-7 has not been definitively established.

Hiser [HI89] has reported brittle-like splits, or laminate tearing, for all of the specimens tested.

These splits are oriented in the direction of crack growth with small amounts of microvoid coalescence in the region between the splits. The size, relative number, and distribution of the splits are approximately constant for various specimen sizes.

Hiser concluded that the splits resulted from separation of the interface between the material matrix and the inclusions (sulfides, aluminides) and/or the splitting of the more brittle alloy rich bonded structure (possibly bainite).

The only apparent difference in the fracture of small and large specimens is the total number of splits and not the relative proportion. A complete micromechanical explanation is not yet available.

4.2 A302B J-R Curve Model Reference

[HI89] showed that although the J-R curves after crack extension are significantly affected by specimen

size, J,c is approximately invariant for specimens ranging in thickness from.5T to 6T. Although not stated by Hiser and Terrell, it is likely that the material response in the J-controlled region is independent of specimen size, and this region of the J-R curve dominates J,c estimation.

Table 4-4 lists the J<<data for the A302B material.

The invariance ofJic with specimen size enables the development of a correlation between J-R response and upper shelf energy level. This correlation is needed to determine the 15

minimum USE for which the plant can be safely operated.

The approach used is to develop a correlation between J,c and USE, and then to determine lower bound J-R curves for each USE level of interest, which are indexed to the Jic value.

The key assumptions made in developing this model are listed below:

The heat treatment and composition of the NMP-1 plates and the materials used in the [HI89] study are similar.

J,c correlates with USE level.

The USE is approximately coristant from the temperature of onset of 100% shear to 550'F.

J,c is approximately constant between 392'F and 550'F.

The 6T data reported in [HI89] is representative of A302B full size vessel behavior.

The justification for each of these assumptions is discussed below.

The specimen size independence of Jic is shown in Table 4-4 and the comparison of the heat treatments and chemical compositions of the NMP-1 plates with the [HI89] study materials is shown in Table 4-3.

4.2.1 J,c - USE Correlation A302B J-R curves, Jic data, and USE data were gathered from References [HA90],

[HI83], [HA82], and [HI89]. Analyses were performed to verify the validity of a correlation between J,c and USE. In a Charpy test on the upper shelf, the crack advance is accomplished by plastic deformation resulting in microvoid coalescence, particle delamination, and in some materials, band delamination. The Charpy test, therefore, measures the total amount of energy required to advance a stable crack in an initiallynotched specimen.

The J-R test is a fundamentally similar process in that the energy per unit area required to advance a stable crack is measured.

Of course, the J-R test differs in specimen

size, parameters

measured, local stress field, and the specimen is always fatigue pre-cracked.

Nevertheless, the basic process which is measured in each of the tests is similar.

In fact, it is logical to expect that the J parameter, measured at any level of crack extension (ha), would correlate with USE.

Hawthorne et. al. [HA82] have demonstrated this observation (Figures 4-8 through 4-10). However, itis not clear that a non-linear dependence is physically correct.

The data used to develop the J,c-USE correlation in the present study are shown in Figure 4-11.

This data set includes both plate and weld data, irradiated and unirradiated data, as well as L-T and T-L orientations.

The linear trend in the data is obvious from the plot.

Notice also that the LINDE-80 weld, S/A 533B 16

weld, and A302B plate dominate the low USE/J<<region of the plot. The fact that Jic USE data for different materials, material heats, and different crack plane orientations correlate suggests a fundamental relationship between the J parameter (at or beyond initiation) and the Charpy USE for materials with similar flow (E,c~~) and strain hardening properties.

Linear regression was performed on the data shown in Figure 4-11.

The linear model yielded R values of 0.93.

As shown in Figure 4-12, a two sigma lower bound confidence interval was determined.

The two sigma lower bound limitcan be determined using the following equations:

J<< = 3.1 (USE), USE < 75 ft-lbs Jic = 363 4 + 7 915 (USE) USE ) 75 f't lbs

where, J<< = in-lb/in USE = ft-lbs The two sigma confidence limitlower bound data are summarized in Table 4-5.

It is important to note that the data used in the J,c-USE correlation is representative of reactor operating temperature performance.

For the data used in the correlation, the Charpy USE was not a strong function of temperature.

A typical Charpy curve for one of the materials used in the correlation is shown in Figure 4-13.

However, the J,c values do vary strongly with test temperature on the upper shelf (Figure 4-14). Therefore, all of the J,c data used in the correlation development were measured between 392'F and 550'F.

The variation over this temperature range is relatively small.

4.22 J-R Curve Determination Now that the J<<-USE correlation has been established, the next step is to develop a procedure for determining the J-R curve, at a given value ofJ<<, which accounts for the specimen size effect reported in [HI89]. The 6T JD-ha data set reported in Reference [HI89] was used to define full thickness vessel behavior.

Once the initial plateau (700 in-lb/in~, Lh = 0.1 in.) is reached, the J-R curve is assumed to be flat. This approach is consistent with current ASTM data validity limits.

The 6T JD-ha data were reduced by the difference between the 6T test J,c value (525 in-lb/in') and the two sigma confidence limitlower bound J,c value (Table 4-5). The results of these analyses are shown in Figure 4-15.

These J-R curves account for the A302B specimen size effect and the inherent data scatter.

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Therefore, they are expected to be conservative lower bounds to the actual material perfoimance.

4.3 A533B J-R Curve Model Reference [EA91] reported two models for A533B base metals; a Charpy model and a pre-irradiation Charpy (CVNp) model. Both models were derived from a modified power law formulation:

J = C1(b,a)~ exp [C3(de)~]

The J, data were fit to the following equation:

ln J~ = ln C1 + C2 ln (ha) + C3(ha)~

using, C2 = d1 + d2 ln C1 + d3 ln B C3 = d4'+ d5 ln C1 + d6 ln B ln C1 = al + a2 ln CVN + a3 T + a4 ln B where b,a = crack extension (in,)

J, = deformation J-integral (kip-in/in' B= specimen net thickness (in,)

T = test temperature ('F)

CVN = Charpy impact energy (ft-lb)

(4-2)

(4-3)

(4-4)

The constants are given in Table 4-6. The CVNp model used expressions (4-2),

(4-3), and (4-4) with the following form for ln C1:

ln C1 = a1 + a2 ln CVNp + a3 T + a4 B+ a5 ttt

where, gt = fluence x 10" (E)1MeV, n/cm')

18

Eason et.al. concluded that the Charpy and CVNP models are equally good for the J, data. Therefore, since the models are equally good, the Charpy model was used for the current case since the functional form is more convenient for determination of J-R curves as a function of USE.

The two sigma lower bound data was obtained by using the standard deviation of the data about the model (Se), which is given in Table 4-6. Therefore, J;de data are determined for the Charpy model, and then multiplied by 0.749 to yield the two sigma lower bound confidence interval. Thus, the final form of equation (4-

1) is:

J = 749.0 Cl(de)~ exp [C3(Lh) ] (in-lb/in')

(4-6)

The Charpy model (equation 4-6) was used to calculate the power law parameters as a function of USE. The results of the calculation are shown in Table 4-7. The following data were used in the model, B= 7.281 in.

T = 525'F C4 = -0.409 and the reduced equations for the power law model are:

C1 = exp (-3.3802919 + 1.13 ln (USE))

C2 = -0.0047931 + 0.116 ln C1 C3 = -0,1397654 - 0.00920 ln Cl Plots of the J-R curves are given in Figure 4-16.

4.4 Material Parameters for Elastic-Plastic Fracture Mechanics Analysis Revision 11 to the ASME Appendix X requires several material parameter inputs in addition to the J-R curve model. The determination of the appropriate parameters for the analysis is described in this section of the report.

4.4.1 Young's Modulus Table I-6.0 of [ASME80] was used to determine the elastic modulus at 500'F.

For carbon steels with carbon content of 0.3 or less, we have:

E = 26.4 x 10'psi, at T = 500'F 19

The modulus decreases with increasing temperature.

The overall effect of the modulus on the elastic-plastic fracture mechanics analysis is to yield more conservative results (-5% between RT and 550'F) as the higher temperature values are used. Therefore, to be conservative, the 500'F modulus was used in the Appendix X analysis.

Since the elastic modulus is essentially insensitive to neutron damage for fluences of interest for LWR operation, it is not necessary to account for radiation damage.

4.42 Poisson's Ratio Poisson's ratio is taken as 0.33 [DI76]. For the material and application being considered, it is not necessaty to adjust for temperature or neutron fluence effects.

4.4.3 Yield Stress Table I-2.1 of Reference [ASME80] shows that from RT to 500'F, there is an 8 ksi drop in yield stress (a). Therefore, the following values for awere used in the Appendix X analysis:

NMP-1 Plate G-307-4 G-8-1 a~at RT ksi 69.4 66.6 o'at 500'~Fc~si 61 58 The RT yield strength data is listed in Reference [MA91]. The use of lower o' values results in more conservative Appendix X analysis results.

Therefore, the 500'F properties were used in the analysis.

The yield stress increases with neutron fluence.

As a result, using the unirradiated adata yields conservative results.

20

I

Table 4-1 Plate Chemis ei ht%

Element Carbon, max Manganese Phosphorous, max Sulfur, max Silicon Molybdenum Nickel ASTM A302B 8c 302M 0.25 1.07-1.62 0.035 0.040 0.13-0.45 0.41-0.64 ASTM A533B 0.25 1.07-1.62 0.035 0.040 0.13-0.45 0.41-0.64 0.37-0.73 NMP-1 Plates'.18-0.20 1.16-1.45 0.012-0.021 0.026-0.034 0.17-0.26 0.45-0.52 0.48-0.56

'ukens ladel analysis by atomic absorption 21

0

Table 4-2 Comparison of the NMP-1 Plate Chemistry with the PG89] Study Material Chemistry Element NMP-1 Plates HI89 Material Carbon Manganese Phosphorous Sulfur Silicon Molybdenum Nickel 0.18 - 0.20 1.16 - 1.45 0.012 - 0.021 0.026 - 0.034 0.17 - 0,26 0.45 - 0.52 0.48 - 0.56 0.21 1.46 0.010 0.021 0.24 0.54 0.23 22

Table 4-3 Comparison of NMP-1 Plate Heat Treatments and Charpy Data with the [HI89] Study Material Heat Treatments and Charpy Data Item NMP-1 Plates S ecimens HI89 Material Heat Treatment 1550-1600'F, 4 hr; water quench, 4 hr 1650+25'F, 6 hr; water quench 1150 +25'F, 10,5 hr., air cool 1200 +25'F, 6 hr; air cool test specimens stress relieved at 1150 +25'F, 30 hrs stress relieve test specimens only 1150 +25'F, 40 hrs 1150+25'F, 24 hr, furnace cool to 600'F, air cool USE (T-L) 68.5 (G-8-3) 53.6 T30 26 23

Table 4-4 Summary of J,c Data as a Function of Specimen Size for A302B'aterial [HI89] Tested at 180'F S ecimen ID V50-113 V50-116 V50-114 V50-117 V50-115 V50-118 V50-119 V50-120 V50-121 Average V50-109 V50-112 Average V50-105 V50-108 Average V50-102 V50-103 Average V50-101 Specimen Thickness 0.5T 0.5T 0.5T 0.5T 0.5T 0.5T 0.5T 0.5T 0.5T 0.5T 1T 1T 1T 2T 2T 2T 4T 4T 4T 6T J Deformation (Jn)

~i-Ib i 662 560 662 405 628 525 611 657 622 592 674 634 654 594 651 623 600 588 594 525

'-Lorientation, USE = 52 ft-lb upper shelf behavior at T>150'F 24

Table 4-5 Two Sigma Confidence LimitLower Bound J,c Data USE

-LBS 10 J~L 30.8 20 61,6 30 92.4 35 107.8 40 123.2 45 138.6 50 154.0 55 169.4 60 184.8 65 200.2 70 215.6 75 230.1 80 269.8 85 309.4 90 348.9 95 100 388,5, 428.1 25

Table 4-6 Constants for J, Model for A533B Steel tEA91]

C2 a4 as C3 1

ds Parameter lnCI a,

Variable (constant) lnCVN or lnCVN T

lnB (constant) lnCI Charpy Model

-2.44 1.13

-0.00277 0.0801 0.0770 0.116

-0.0412 CVN, Model

-2.53 1.15

-.00270 0.0760

-0.0104 0.0770 0.116

-0.0367 C4 s

6 0 Points S,

(constant) lnCI hiB (exponent) ln units

-0.0812

-0.00920

-0.0295

-0.409 2295 0.144

-0.0812

-0.00920

-0.0263

-0.408 2295 0.145 Raios

-1.645 S,

-1 S,

-2 S,

-3 S, 0.789 0.866 0.749 0.649 0.788 0.865 0.748 0.647 26

I

Table 4-7 A533B Material Model for NMP-1 Material Condition 10 ft-lb USE 20 ft-lb USE 30 ft-lb USE 40 ft-lb USE 50 ft-lb USE 60 Mb USE 70 ft-lbUSE 80 ft-lb USE 90 ft-lb USE

, 100 ft-lb USE C1 0.4591535 1.0048975 1.5889305 2.1993061 2.8300492 3.4775133 4,1392215 4.8133735 5.4985973 6.1938100

-0.0950841

-0.0042264 0.0489220 0.0866314 0.1158810 0.1397797 0.1599858 0.1774891 0.1929281 0.2067387 C3

-0.1326044

-0.1398103

-0.1440256

-0.1470163

-0.1493361

-0.1512315

-0.1528341

-0.1542223

-0.1554467

-0.1565421 27

Mn vs. S for LWR VESSEL MATERIALS 0.04 0.03 R

0.02 e

Q) 0.01 0.00

~

~ ~ ~ o ~ ~ o ~ o ~ e

~

~

~

W ~

~o~

~ 5

~

~ ow o

~ \\ ~ o ~ o ~ ~

~ ~

~

~ oe ~

...........ONQP.;.1.............

h

\\

h h

h0

+ h

~Q ooooooooo

~

~ ~

~

0

+ oO0

+4CO+:

4040: +

0 i+ +o: 0

- ~. ~ ~oo4t.

+ A533B Plate a A608 Plate

> A302B Plate 0 A302M Phte 00 0.5 1.0 Manganese (Wt. %)

l.5 2,0 Figure 4-1 Plot of S and Mn Levels for LWR Pressure Vessel Materials 28

USE vs. S for LWR VESSEL MATERIALS 200

~ g l50 LL

@ 100 C

UJ CO 50 0

~ ~ ~ o ~ ~

~ ~ o ~

~ ~ ~\\ ~ oo

~

~

a+

~

~

~

y ~

0:

go ~ oooooo ~ o $ toro Ot'

'o'g

~o 0I h

~oo

~ o o ~

og ohh y NMP-1

'+ A6338 Rate

~ A608 Plate

< A3028 Plate 0 A302M Rate 0.00 0.01 0.02 Sulphur (Wt. %)

0.03 0.04 Figure 4-2 Plot of USE vs. S Content Showing the Detrimental Effect of S on the USE Level 29

USE vs. Ni for LWR VESSEL MATERiALS 200 150 I-8 ~00 UJ CO 60

~ ~ e ~ ~ ~ e

~ ooooo ~ 1

~ e o

e

~ oo ~

~ ~ e eo

\\

~ e ~ o ~ e ~ e ~ ~

e

~ ~

~ e ~ e ~

~ ~\\ ~ ~ o ~ ~ o ~

oy p Qgp

~ o ~ ~

~ e ~ e ~

~ ~ e ~ o ~\\ ~

~ p

~ oe ~op ~

~ ~

~

o$

~ eo

~ ~ ~

~ ~

~

~

~Ng

~

g ~ E

+ A6338 Plate

~ A608 Rate

< A3028 Plate 0 A302M Plate 0.0 0,1 02 0.3 Oe4 0.6 0,6 0.7 0.8 Nickel ONt. %)

Figure 4-3 Plot of USE vs. Ni Content Showing the Generally Beneficial Effects of Ni on the USE Level 30

r

USE vs. Ni for LWR VESSEL MATERIALS 200 I

150 LI-I

@ 100 C

UJ I

50 0

~ S-.019

~

~

~ ~

~ )eo

~ ~ ~ ~ ~

.022'i.026'

~

~

Og ~ ~

~ 0 ~ ~

~ o

~

~

4I pS.0't9 y teo."o S.9't7

~

~

qp p Sa.020

~

~

~

~ ~

~

~ ~

~ ~ A

.:pS-,030

+ A533B Plate

~ A508 Plate

< A302B Plate 0 A302M Plate 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 Nickel ONt. %)

Figure 4-4 Plot of USE vs, Ni Content Showing the Impact of S Content in Counteracting the Beneficial Ni Effect 31

4000 3500 3000 c

2500 C

7 2000 1500 1000 500

~o

~gx

+x xxx

~~+4 ++

+

o p

p p

0 p

p

0. 394T CT L 0.5T CT X 0.5T CT 0

1T CT P

2T CT 0

0.

1

0. 2

0. 3

0. 4

0. 5

0. 6

0. 7 CRACK EXTENS!ON (in.)

Figure 4-5: J-R Curves for Linde 80 Welds [JOY91]

32

4000 3500 3000 2500 C

O 2000 C

1500 Limit of Extended Validity Region for 1T Specimens 1T~

0. 5T~

0.394T 1000 I

Limit of Extended Validity.Region for 1/2T 'Specimens Cl 2T CT DATA 500 Limit of Extended Validity Region for 0.394T Specimen 0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 CRACK EXTENSlON (in.)

Figure 4-6; Extrapolations on Small Specimen J-R Curves - Linde 80 Welds [JOY91]

33

A302B J-R DATA FOR VARIOUS SPECIMEN THICKNESSES 1600 OJ 1000 CO o

600 O

0 0

0

• 4 O

4

~ ~ ~

~

~ 0 g+

~ ~ ~ JR

~ e) ~

gl

+444a

~ ~gygH+

~ '; ~ ~

k a

~

~

~

~

~QHSA

~

~

cI 0.5T DATA

< 0.5T DATA 0 0,5T DATA 4 0.5T DATA

• 0.5T DATA

• 0.5T DATA 0 1T DATA

+ 1T DATA o 2T DATA a 2T DATA

< 4T DATA 4 4T DATA

~ 6T DATA Delta a (In.)

Figure 4-7 Comparison of J~-R Guves for A302B Plate (Data Taken From tHI89])

34

EPRI NUCLERR VESSEL STEELS 328 288 C, iT-CT, 28-25/

SG Filled Symbols

= Irradiated i68 AA A h A

h 58 i88 Cv (joule) 288 Figure 4-8 Comparison of J,e and the Cv Upper Shelf Level for All Steels Investigated [HA82]

35

0

EPRI NUCLERR VESSEL STEELS 288oC~

1T CT 28 25<

SG Filled Symbols

= Irradiated 588 0

8

~O 0

OO ~

Oy Q

~ y

~

~

88 128 Cv (joule) 168 Figure 4-9 Comparison of Cv Upper Shelf Level with the J Level at a Point on the R Curve Where Jff = 4.4.

Here, the Correlation. with C shelf is Better than that between J,o and the Cv Shelf [HA82]

36

EPRI NUCLERR VESSEL STEELS 288oC 1T CT 28 25'G Filled Symbols

= Irradiated 688 II 488 A/

h L hL L

L

~k A

188 Cv (joule)

Figure 4-10 Comparison of Cv Upper Shelf Level with the J Level at a Point on the R Curve where Jff = 8,8 for AllMaterials Investigated Here, the Correlation with Cv Shelf is Better than that Between Both J,o and J at JfI' 4.4 and the Cv Shelf [HA82]

37

Jic/USE Correlation Data 2000 1500 1000 b

kg p'

0 ASOSB PLATE AGSSB

'LATE A608 FORGING S/A GSSB WELD LINDE-80 WELD LINDE-0091 WELD 500 50

'f 00

't 50 Upper SheII Energy tFt-Lbs)

Figure 4-11 Data Set Used to Develop J,e-USE Correlation 38

2000 1500 C

1000 I

O 500

~ g f.

~

~

~

~

i~

~

~

~

I

~:

~ I

- - O-'-- - ~-e.e !- - - ------"

A

~brae

~

~

~:

0 50 100 USE (Ft-Lbs) 150 Figure 4-12 Jic USE Correlation and Two Sigma Lower Bound Confidence Limit 39

Tetnperature

('F )

288 388 488 68812S 125 P

188 l5 75 58 R 382-B (UBR-I6, Capsul e Fl, Rs-Irrad 1 ated)

CCE-23 188 J2 I

75 C

CLl 58 Q.

4 188 158 288 258 388 Teepe rature ('1 56 F 84 J 50 ~ 45 J 47.67 oC 64'8 oC Cv a 30 f't-lb <41 J) at T ~

119.?

oF 48'?

4C Upper Shelf'nergy

~

79. 1 f't-lb 107.3 J

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%+%%%%%%%+%%%%%%%+%+

Cv

~

A +

B tanh[<T - To)rCl I

Netr\\c 8

~

41, 92 f't-1 b B

37.21 f't-lb C

~

85 81 oF To

~

148.24 4F Figure 4-13 A302B Charpy Data Illustrating the Weak Temperature Dependence of the USE on Temperature [HA90]

40

!Ormtux Vtt i

Nt lOE CN 2N

'4 R

I!O IN IhiNHiit~I K I ILK'fall

~ )4 Comit

-IN IN IDFCRAtLK I~ C'I W

Rl ttmetm I r~

~

283

~R(~PIi~(gr )

IA1 CN lN

> I!O aS(

IN 4

tr<

4 LhiftH<ittl

, ~

CI:4 tVW'4 >

0

' )'II (elH LN IN "

0i8

-IN I

IN cN

~ Nl

!occam ( c) a I~ILFCf'F) iN IQC, tN A

PI 2K>

Qo IN C

TV'hstrlltltll CE ! i'5>

> J~ Cote QO IN

.N Ib!

ICO W

LO I~~tm l Ct Figure 4-14 Plot of K,c vs. Test Temperature Showing the Strong Temperature Dependence on the Upper Shelf [HA90]

41

A302B J-R CURVES FOR VARIOUS USE LEVELS

~ TWO SIGMA LOWER BOUND J-R DATA 0 6T MEAN J-R DATA AT 180 F 52 Ft-Lbs (TL) 900 800 700 C~ 600 I

500

.8 400 o 300 200 0

0 0

0

~oo 0 0;y o 4

g oo

~ ~ ~

~

E-'I F-8:,

.g,,o, BEItoooT,, PA% ~. k, o,,~,, A, ~,, ~

4; ~.o Aoo.o oo ~,, 4

~ ~

~

J p oo

~ ooooooooo

~ ~'~

~

~

~

~

~

~

~

".AOFioR o

'to O

j o4 % A44ooo ~

5

~

~ ~

~

~

~

~

~

~

~ ~ ~ ~ o ~ oo

~

~

~

~

-."" -"- ""ig':;";";;"";-. ";--;-.'AN".T;o;F4-.t ~.

O Ft,'~E,.

100 0

0 Delta a (In.)

Figure 4-15 Two Sigma Lower Bound J-R Curves for A302B Thick Section Material (6T Data Taken From [HI89])

42

A533B J-R CURVES FOR VARIOUS USE LEVELS 6000 5000

~ 4000 I

C 3000 O

o 2000 O

1000 0

0 USE-100FT-LB

. --: OSE 90 FT-LB

-..........,'..................-......,'..USE..80.FT.-.LB.

r "r

2 USE-70 FT-LB USE 80 FT LB I

USE 50 FT-LB r

, I"I'~ '".:-.:USE-40 FT-LB

USE 30 FT-LB 2 USE 20 FT-LB

'SE 10 FT-LB Delta a On.)

Figure 4-16 Two Sigma Lower Bound J-R Curves for A533B Thick Section Material 43

5.0 Elastic-Plastic Fracture Mechanics Assessment

~

~

~

~

~

~

The USE'code [USE92], Version 2.0, was used for calculation of the minimum allowable USE subject to the draft Appendix X (Revision 11) evaluation criteria. The USE'Version 2.0 code has been validated in accordance with the requirements of the MPM Research & Consulting Nuclear Quality Assurance Program. USE~ allows J-R data to be input as pointwise data or in the form of power law coefficients.

The pointwise data input option was used.

5.1 Model Description In addition to the material model input, USE 2.0 requires the following input parameters:

Vessel Wall Thickness Vessel Inner Radius 7.281 in (FSAR Table V-1) 106.344 in (FSAR Table V-1)

Maximum Accumulation Pressure = 1.1 Design Pressure = 1375 psig (Technical Specification Bases for 2.2.1)

Maximum Cooldown Rate 100'F/hr As stated in the FSAR, the 1375 psig pressure and 100'F/hr cooldown bound all the Service Level A and B loadings.

5.2 Calculations for A302B Material Model 5.2.1 Plate G-8-1 Analysis The results of the Plate G-8-1 analysis, using the A302B material model, are shown in Figures 5-1 through 5-6. Based on these calculations, and the Reference

[ASME92] evaluation criteria, the limiting case is the axial flaw (L-T material properties).

Application of the flaw instability criterion, which is the limiting criterion, results in an allowable USE range of 23 ft-lbs or higher as shown in Figure 5-5.

5.22 Plate G-307-4 Analysis The results of the plate G-307-4 analysis using the A302B material model are shown in Figures 5-7 through 5-12, As in the case of plate G-8-1, the limiting case is the axial flaw orientation.

Application of the flaw instability criterion, which is the limitingcriterion, results in an allowable USE range of 23 or higher as shown in Figure 5-11.

5.3 Calculations for A533B Material Model 5.3.1 Plate G-8-1 Analysis The results of the plate G-8-1 analysis using the A533B material model are shown in Figures 5-13 through 5-18. As in the A302B model analysis, the limiting case is the axial flaw orientation.

Application of the ASME Appendix X criteria indicates that the minimum USE level is below 10 ft-lbs, when the A533B material model is applied.

5.32 Plate G-307-4 Analysis The results of the plate G-307-4 analysis using the A533B material model are shown in Figures 5-19 through 5-24. As in the plate G-8-1 analysis, using this material model, the minimum USE level is below 10 ft-lbs.

5.4 Summary of Conditions Analyzed The results of the elastic-plastic fracture mechanics assessment are shown in Table 5-1.

As expected, the A302B material model yields the most conservative results.

As discussed in Section 4.0, the A302B material model best represents the NMP-1 beltline plates.

The ASME flaw stability criterion is more conservative than the 0.1 inch flaw growth criterion for the NMP-1 plates.

Based on these calculations, it has been concluded that the NMP-1 plates G-8-1 and G-307-4 must be maintained above 23 ft-lbs.

45

Table 5-1 Minimum Upper Shelf Energy Level (Axial Flaw) for NMP-1 Plates Based on the ASME Draft Appendix X Evaluation Criteria for Service Levels A and B Minimum USE (Ft-Lbs)

Plate G-8-1 G-8-1 G-307-4 G-307-4 Material Model A302B A533B A302B A533B Flaw Growth of 0.1 in, Criterion Ji < Jo.i 13

<10 13

<10 Flaw Stability Criterion P'

1.25P, 23

<10 23

<10 46

10 Ft.-Lbs.

NINE MILE POINT UNIT 1

PLATE G-S-1 A302B Model/L-T Orientation/Axial Flaw 1000 900 30 Ft.-Lbs.

800 40 Ft.-Lbs.

700 600 C

600 Ca C

400 8

300 CL

~

~

60 Ft.-Lbs.

60 Ft.-Lbs.

70 Ft.-Lbs.

80 Ft.-Lbs.

200 90 Ft.-Lbs.

100 100 Ft.-Lbs.

0.00 0.20 0.40 0.60 0.80 1e00 Delta a (In.)

~

J-Applied at 0.1ln.

Figure 5-1 Evaluation Using Criterion for Flaw Growth of 0.1 in. for Plate G-8-1 Modelled Using A302B Material Model (Axial Flaw) 47

10 Ft.-Lbs.

NINE MILE POINT UNIT 1

PLATE G 1 A302B Model/T-L Orientation/Circum.

Flaw 1000 900 30 Ft.-Lbs.

800 40 Ft.-Lbs.

700 IO eoo c

600 C0 Ctt 400 6

300 Ch 200 100 0

jli II I

li 60 Ft.-Lbs.

eO Ft.-Lbs.

70 Ft:Lbs.

eo Ft.-Lbs.

90 Ft.-Lbs.

100 Ft.-Lbs.

0.00 0.20 0.40 0.80 0.80 1.00 Delta a (In.)

0 J-Applied at 0.1ln.

Figure 5-2 Evaluation Using Criterion for Flaw Growth of 0.1 in. for Plate G-8-1 Modelled Using A302B Material Model (Circumferential Flaw) 48

10 Ft.-Lbs.

NINE MILE POINT UNIT 0

PLATE G 0 A302B Model/L-T Orientation/Axial Flaw 1000 900 30 Ft.-Lbs.

800 40 Ft.-Lbs.

700 C

800 C

600 C0 400 6

300 O

60 Ft.-Lbs.

80 Ft.-Lbs.

70 Ft.-Lbs.

80 Ft.-Lbs.

200 90 Ft.-Lbs.

100 0

0.00 0.20 0.40 0.80 0.80 1.00 Tearing Modulus 100 Ft.-Lbs.

T-Applied Figure 5-3 J-T Material and J-T Applied Curves for Plate G-8-1 Modelled Using A302B Material Model (Axial Flaw) 49

10 Ft.-Lbs.

NINE MILE POINT UNIT 1

PLATE Q-S- 0 A302B Model/T-L Orientation/Circum.

Flew 1000 900 30 Ft.-Lbs.

800 40 Ft.-Lbs.

700 C

CO 800 C

600 c0 C

400 6

300 Q

60 Ft.<<Lbs.

80 Ft.-Lbs.

70 Ft.-Lbe.

80 Ft.-Lbs.

200 90 Ft.-Lbs.

100 0

0.00 0.20 0.40 0.80 0.80 1.00 Tearing Modulus 100 Ft.-Lbs.

T-Applied Figure 5-4 J-T Material and J-T Applied Curves for Plate G-8-1 Modelled Using A302B Material Model (Circumferential Flaw) 50

NINE MILE POINT UNIT 1

PLATE 6 0 A302B Model/L-7 Orientation/Axial Flaw

~ Onset of

Accumulation 1.26'Accum.

Flaw lnstab.

Pressure Pressure 2000 1900 1800 1700 1B00 1500 ro 1400 1300 1200 1100 1000 0

10 20 30 40 60 70 80 Upper Shelf Energy (Ft.-Lbs.)

Figure 5-5 Evaluation Using Criterion for Flaw Stability for Plate G-8-1 Modelled Using A302B Material Model (Axial Flaw) 51

NINE MILE POINT UNIT I PLATE G 1 A302B Model/T-l. Orientation/Circum.

Flaw

~ Onset of

Accumulation 1.26'Accum.

Flaw Instab.

Pressure Pressure 4000 3500 3000 CO0 2500 CO COI La CL 2000 1500 1000 0

10 20 30 40 50 80 70 80 Upper Shelf Energy (Ft.-Lbs.)

Figure 5-6 Evaluation Using Criterion for Flaw Stability for Plate G-8-1 Modelled Using A302B Material Model (Circumferential Flaw) 52

10 Ft.-Lbs.

NINE MILE POINT UNIT 1

PLATE G-307-4 A302B Model/L-T Orientation/Axial Flaw 1000 900 30 Ft.-Lbs.

800 40 Ft.-Lbs.

700 C

CO 600 C

600 C0 C

400 6

300 C!

200 100 0

/i) yl

/I 60 Ft.-Lbs.

60 Ft.-Lbs.

70 Ft.-Lbs.

80 Ft.-Lbs.

90 Ft.-Lbs.

100 Ft.-Lb@.

0.00 0.20 OAO 0.60 0.80 1.00 Delta a (In.)

~

J-Applied at 0.1ln.

Figure 5-7 Evaluation Using Criterion for Flaw Growth of 0.1 in. for Plate G-307-4 Modelled Using A302B Material Model (Axial Flaw) 53

10 Ft.-Lbs.

NINE MILE POINT UNIT 1

PLATE G-307-4 A3028 Model/T-L Orientation/Circum.

Flaw 1000 900 30 Ft.-Lba.

800 40 Ft.-Lbs.

700 C

IO 800

'C 600 C0 C

400 6

300 Ch 200 100 0

/

Il rt 60 Ft.-Lba.

80 Ft.-Lbe.

70 Ft.-Lbe'.

80 Ft.-Lba.

90 Ft.-Lbs.

100 Ft.-Lb@.

0.00 0.20 OAO 0.80 0.80 1.00 Delta a (In.)

~

J-Applied at 0.1ln.

Figure 5-8 Evaluation Using Criterion for Flaw Growth of 0.1 in. for Plate G-307-4 Modelled Using A302B Material Model (Circumferential Flaw) 54

10 Ft.-Lbs.

NINE MILE POINT UNIT 0

PLATE G-307-4 A302B Model/L>>T Orientation/Axial Flaw 1000 900 30 Ft.-Lbs.

800 40 Ft.-Lbs.

700 C

CO 800 c

600 C0 Ctl 400 E

300 CL 60 Ft.-Lbs.

eO Ft.-Lbs.

70 Ft.-Lbs.

80 Ft.-Lbs.

200 90 Ft;lbs.

100 0

o.oo o.2o o.4o o.eo o.eo 1.0o Tearing Modulus 100 Ft.-Lb@.

T-Applied Figure 5-9 J-T Material and J-T Applied Curves for Plate G-307-4 Modelled Using A302B Material Model (Axial Flaw) 55

10 Ft.-Ltt~.

NINE MILE POINT UNIT 1

PLATE G-307-4 A302B Model/7-L Orientation/Clroum.

Flaw 1000 900 30 Ft.-Lbe.

800 40 Ft.-Lbe.

700 C

IO 800 C

600 C0 C

400 6

300 Cl 60 Ft.-Lbe.

80 Ft.-Lbe.

70 Ft,-Lbe.

80 Ft.-Lbe.

200 90 Ft.-Lbe.

100 0

0.00 0.20 0.40 0.80 0.80 1.00 Tearing Modulus 100 Ft.-Lb@.

T-Applted Figure 5-10 J-T Material and J-T Applied Curves for Plate G-307-4 Modelled Using A302B Material Model (Circumferential Flaw) 56

NINE MILE POINT UNIT 1

PLATE G-307-4 A302B Model/L-7 Orientation/Axial Flaw

~ Onset of Accumulation 1.26'Accum.

Flaw Instab.

Pressure Pressure 2000 1900 1800 1700 1800 I

a 1500 Cl COI 1400 1300 1200 1100 1000 10 20 30 50 80 70 80 Upper Shelf Energy (Ft.-Lbs.)

Figure 5-11 Evaluation Using Criterion for Flaw Stability for Plate G-307-4 Modelled Using A302B Material Model (Axial Flaw) 57

NINE MILE POINT UNIT 1

PLATE Q-307-4 A302B Model/T-L Orientation/Circum.

Flaw

~ Onset of Accumulation 1.26'Accum.

Flaw Instab.

Pressure Pressure 4000 3500 3000 COC 2500 CO tO A

2000 1500 1000 10 20 SO 40 50 50 70 80 Upper Shelf Energy (Ft.-Lbs.)

Figure 5-12 Evaluation Using Criterion for Flaw Stability for Plate G-307-4 Modelling Using A3028 Material Model (Circumferential Flaw) 58

10 Ft.-Lbe.

NINE MILE POINT UNIT 1

PLATE C-8-1 A533B Model/L-T drientation/Axial Flaw 6000 30 Ft.-Lbs.

4000 40 Ft.-Lbs.

C CO 3000 I

C C0 C

2000 E

La.0 Cl 1000 60 Ft.-Lbs.

80 Ft.-Lbs.

70 Ft.-Lbs.

80 Ft.-Lbs.

80 Ft.-Lbs.

I

/

I 100 Ft.-Lbe.

0 0.00 0.20 0.40 0.80 0.80 1.00 Delta a (In.)

~

J-Applied at 0.1ln.

59 Figure 5-13 Evaluation Using Criterion for Flaw Growth of 0.1 in. for Plate G-8-1 Modelled Using A533B Material Model (Axial Flaw)

10 Ft.-Lbs.

NINE MILE POINT UNIT 1

PLATE Q-8-1 A633B Model/T-L Orientation/Circum.

Flaw 6000 30 Ft.-Lbs.

4000 40 Ft.-Lbs.

CO 3000 C

C0 sgs4 CI 2000 6

I Cl 60 Ft.-Lbs.

80 Ft.-Lbs.

70 Ft.-Lbs.

80 Ft.-Lbs.

1000 0

I

/

I I

90 Ft.-Lbs.

100 Ft.-Lbs.

0.00 0.20 0.40 0.80 0.80 1e00 Delta a (In.)

~

J-Applied at 0.1 In.

Figure 5-14 Evaluation Using Criterion for Flaw Growth of 0.1 in. for Plate G-8-1 Modelled Using A533B Material Model (Circumferential Flaw) 60

10 Ft.-Lbs.

NINE MILE POINT UNIT 1

PLATE Q 1 A53SB Model/L-T Orientation/Axial Flaw 6000 80 Ft.-Lbs.

4000 40 Ft.-Lbs.

C IO 3000 t

C0 2000 6

I Q

60 Ft.-Lbs.

80 Ft.-Lbs.

70 Ft.-Lb@.

80 Ft.-Lbs.

1000 90 Ft.-Lbs.

0 1

2 Tearing Modulus 100 Ft.-Lbs.

T-Applied Figure 5-15 J-T Material and J-T Applied Curves for Plate G-8-1 Modelled Using A533B Material Model (Axial Flaw) 61

10 Ft.-Lbe.

NINE MILE POINT UNIT 1

PLATE G-8-1 A5338 Model/T-L Orientation/Circum.

Flaw 6000 SO Ft.-Lbe.

4000 40 Ft.-Lbe.

c CO 3000 I

C Ca

~galti 2000 6

Ch 60 Ft.-Lbe.

80 Ft.-Lbe.

70 Ft.-Lbe.

80 Ft.-Lbe.

1000 90 Ft.-Lbe.

100 Ft.-Lbs.

Tearing Modulus T-Applied Figure 5-16 J-T Material and J-T Applied Guves for Plate G-8-1 Modelled Using A533B Material Model (Circumferential Flaw) 62

NINE MILE POINT UNIT I PLATE G 0 A633B Model/L-T Orientation/Axial Flaw R Onset of Accumulation 1.26'Accum.

Flaw Instab.

Pressure Pressure 5000 4500 4000 3500 CO CL sooo COloI Le 2500 2000 1600 1000 0

10 20 30 40 60 eo 70 80 Upper Shelf Energy (Ft.-Lbs.)

Figure 5-17 Evaluation Using Criterion for Flaw Stability for Plate G-8-1 Modelled Using A533B Material Model (Axial Flaw) 63

NINE MILE POINT UNIT I PLATE G-8-1 A633B Model/T-L Orientation/Ciroum.

Flaw

~ Onset of Accumulation 1.26'Accum.

Flaw Instab.

Pressure Pressure 10 CO B

CL~

o C g

O CO w to~

6 Q

0 10 20 30 40 50 80 70 80 Upper Shelf Energy (Ft.-Lbs.)

Figure 5-18 Evaluation Using Criterion for Flaw Stability for Plate G-8-1 Modelled

'sing A533B Material Model (Circumferential Flaw) 64

10 Ft.-Lbs.

NINE MILE POINT UNIT 1

PLATE G-307-4 A533B Model/L-T Orientation/Axial Flaw 20 Ft 6000 80 Ft.-Lbs.

4000 40 Ft.-Lbs.

tO 3000 C

c0 2000 6

0I Cl 60 Ft.-Lbs.

BO Ft.-Lbs.

70 Ft.-Lbs.

80 Ft.-Lbs.

1000 90 Ft.-Lbs.

0 0.00 0.20 0.40 0.80 0.80 1.00 Delta a (In.)

100 Ft.-Lbs.

~

J-Applied at 0.1ln.

Figure 5-19 Evaluation Using Criterion for Flaw Growth of 0.1 in. for Plate G-307-4 Modelled Using A533B Material Model (Axial Flaw) 65

10 Ft.-Lbs.

NINE MILE POINT UNIT I PLATE G-307-4 A5338 Modei/T-L Orientation/Circum.

Ftaw 5000 SO Ft.-Lbs.

4000 40 Ft.-Lbs.

C CO 3000 C

C0 CO 2000 8

I 1000

/

(/1 50 Ft.-Lba.

60 Ft.-Lbs.

70 Ft.-Lbs.

80 Ft.-Lba.

90 Ft.-Lba.

0 0.00 0.20 OAO 0.80 0.80 1.00 Delta a (In.)

100 Ft.-Lbs.

~

J-Applied at 0.1 In.

Figure 5-20 Evaluation Using Criterion for Flaw Growth of 0,1 in, for Plate G-307-4 Modelled Using A533B Material Model (Circumferential Flaw) 66

10 Ft.-Lbs.

NINE MILE POINT UNIT I PLATE G-307-4 A533B Model/L T Ol'Ie>hktla</Axl+I Flaw 20 Ft 6000 SO Ft.-Lbs.

4000 40 Ft.-Lbs.

C IO 3000 C

C0 sgs4 2000 6

I O

50 Ft.-Lbs.

80 Ft.-Lbs.

70 Ft.-Lbs.

80 Ft.-Lbs.

1000 90 Ft.-Lbs.

0 1

2 Tearing Modulus 100 Ft.-Lbs.

T-Applied Figure 5-21 J-T Material and J-T Applied Curves for Plate G-307-4 Modelled Using A533B Material Model (Axial Flaw) 67

10 Ft.-Lbs.

NINE MILE POINT UNIT 1

PLATE G-307-4 A533B Modei/T-L Orientation/Circum.

Flaw 20Ft Lbs 5000 SO Ft.-Lbe.

4000 40 Ft.-Lbs.

C Cl SOOO I

C0 2000 E

Q Cl 50 Ft.-Lbs.

BO Ft;Lbs.

70 Ft.-Lbe.

80 Ft.-Lbs.

1000 90 Ft.-Lbs.

0 1

2 Tearing Modulus 100 Ft.-Lbe.

T-Applied Figure 5-22 J-T Material and J-T Applied Curves for Plate G-307-4 Modelled Using A533B Material Model (Circumferential Flaw) 68

NINE MILE POINT UNIT

'I PLATE Q-30? -4 A6338 Model/L-T Orientation/Axial Flaw S Onset of

Accumulation 1.26'Accum.

Flaw Instab.

Pressure Pressure

'ooo 4600 4000 3500 CO 3000 Ot 2500 2000 1600 1000 0

10 20 so 40 6o eo 70 80 Upper Shelf Energy (Ft.-Lbs.)

Figure 5-23 Evaluation Using Criterion for Flaw Stability for Plate G-307-4 Modelled Using A533B Material Model (Axial Flaw) 69

NINE MILE POINT UNIT

'I PLATE G-307-4 A633B Model/T-L Orientation/Circum.

Flaw 8 Onset of Accumulation 1.26'Accum.

Flaw Instab.

Pressure Pressure 10 I

8 CL~

o C OS

CONf, 6

I 10 20 30 40 50 80 70 80 Upper Shelf Energy (Ft.-Lbs.)

Figure 5-24 Evaluation Using Criterion for Flaw Stability for Plate G-307-4 Modelled Using A533B Material Model (Circumferential Flaw) 70

6.0 Summary and Conclusions The elastic-plastic fracture mechanics analyses performed have shown that the axial flaw is the limiting orientation.

The NMP-1 A302M beltline plates are best modelled using an A302B J-R curve model.

During the September 30, 1992, meeting, the NRC indicated reluctance in accepting the 0.8 L-T to T-L conversion without additional statistical evidence.

Work is currently being conducted to demonstrate that an L-T to T-L conversion factor above 0.65 is appropriate for the NMP-1 beltline plates.

Nevertheless, as shown in Table 6-1, there is at present sufficient margin against ductile &acture using the RG1.99(2) generic model with a 0.65 conversion factor.

Since 1972, the T-Lorientation has been required by ASME and used in the nuclear industry for analysis of pressure vessels.

The 50 ft-lb screening criterion is also evaluated based on the T-L orientation. However, a more consistent approach would be to evaluate the axial flaw using L-T Charpy USE data, and to evaluate the circumferential flaw using T-L Charpy data.

As shown in Table 6-2, when the appropriate orientation is considered, the margin between the minimum allowable USE and the predicted actual USE at EOL is on the order of 38 ft-lbs. This margin of safety is in addition to the safety factors applied to the ASME Appendix X equations.

Therefore, it has been concluded that the NMP-1 vessel is safe in terms of ductile fracture failure through EOL for Service Level A and B loadings.

The Level C and D loadings are currently being analyzed and willbe reported to the NRC in a separate report in the near future.

71

Table 6-1 Comparison of the Minimum Upper Shelf Energy Level (Axial Flaw) for NMP-1 Plates Based on the ASME Draft Appendix X Evaluation Criteria for Service Levels A and B with the Regulatory Guide 1.99(2) Model Estimates Minimum Allowable USE (Ft-Lbs) for Axial Flaw (L-T Orientation)

RGL99(2)

Model'T-L Orientation)

Plate Material Model Flaw Growth of 0.1 in. Criterion JI < Jai Flaw Stability Criterion P'

1.25P, Minimum USE (Ft-lbs) Prcdiction at EOL G-8-1 G-307-4 A302B A302B 13 13 23 23 42.6 40.0

'eneric model applied without plant-specific data 72

\\

Table 6-2 Minimum Upper Shelf Energy Level Margins for NMP-1 Plates for Service Level A and B Loadings Plate G-8-1 G-8-1 Material Model A302B A302B Flaw Orientation Axial Circumferential Minimum Allowable USE t-Lb 23

<10 Charpy Specimen Orientation L-T T-L Conservatively Predicted Charpy USE at

~EQL'Lb 65.6 42.6 Margin

+t-L+bs 42.6

>32.6 G-307-4 A302B G-307-4 A302B Circumferential 23

<10 L-T T-L 61.6 40.0 38.6

>30.0 25 EFPY exposure projected for EOL in 2009. The RG1.99(2) model, without plant-specific data, was used to conservatively estimate the minimum EOL USE levels.

73

4

7.0 References

[ASME80]

ASME Boiler and Pressure Vessel code,Section III, "Rules for Construction of Nuclear Power Plant Components", July 1, 1980

[ASME92]

ASME, Draft Code Case N-XXX, "Assessment of Reactor Vessels with Low Upper Shelf Charpy Energy Levels", Revision 11, May 27, 1992.

[BR92]

NRC Letter from D. S. Brinkman to B.R. Sylvia, November 13, 1992.

[CE90]

"Niagara Mohawk Power Corporation Nine Mile Point Unit 1 Reactor Vessel Weld Materials", Report No. 86390-MCC-001, ABB Combustion Engineering Nuclear Power Combustion Engineering, Inc., Windsor, Connecticut, June, 1990.

[DI76]

Dieter, G.E., Mechanical Metallurgy, Second Edition, McGraw-Hill, 1976.

[EA91]

Eason, E.D., Wright, J.E., Nelson, E.E., "MultivariateModeling ofPressure Vessel and Piping J-R Data", NUREG/CR-5729, May, 1991.

[FR92]

Freyer, P., Manahan, M.P., Presentation to Project FERMI, "Plant Life Extension Technology: Non-Destructive Reactor Materials Embrittlement Monitoring Using Positron Annihilation", May, 1992.

[HA82]

Hawthorne, J.R., Menke, B.H., Loss, F.J., Watson, H.E., Hiser, A.L., Gray, R.A "Evaluation and Prediction of Neutron Embrittlement in Reactor Pressure Vessel Materials", EPRI/NP-2782, prepared for EPRI, December, 1982.

[HA90]

Hawthorne, J.R., Hiser, A.L., "Influence of Fluence Rate on Radiation-Induced Mechanical Property Changes in Reactor Pressure Vessel Steels", NUREG/CR-5493, March, 1990.

[HI83]

Hiser, A.L., Fishman, D.B., "J-R Curve Data Base Analysis of Irradiated Reactor Pressure Vessel Steels", prepared for EPRI December, 1983.

[HI89]

Hiser, A.L., Terrell, J.B.,

"Size Effects on J-R Curves for A302B Plate",

NUREG/CR-5265, January, 1989.

[JOY91]

Joyce, J.A., Hackett, E.M., "Extension and Extrapolation of J-R Curves and Their Application to the Low Upper Shelf Toughness Issue", NUREG/CR-5577, March, 1991.

74

v

[MA85]

Manahan, M.P., "Procedure for the Determination of InitialRT~ in Cases where Limited Baseline Data are Available", November, 1985.

[MA85a]

Manahan, M.P., Quayle, S.F., Rosenfield, A.R., and Shetty, D.K., "Statistical Analysis of Cleavage-Fracture Data", Invited paper, Conference Proceedings ofthe International Conference and Exhibition on Fatigue, Corrosion Cracking, Fracture Mechanics, and Failure Analysis, Salt Lake city, December 2-6, 1985.

[MA90]

Manahan, M.P., "Nine MilePoint Unit 1 RT~ Determination", Final Report from MPM Research & Consulting to NMPC, September 28, 1990.

[MA91]

Manahan, M.P., "Nine MilePoint Unit 1 Surveillance. Capsule Program", NMEL-90001, January 4, 1991.

[MA91b]

Private communication, M.P. Manahan (MPM Research &Consulting) to J, Helm (Columbia University), "Physically Based Upper Shelf Fracture Model forFerritic Pressure Vessel Steels", January, 1991.

[MA92]

[McFRAC]

Manahan, M.P., Soong, Y., "Response to NRC Generic Letter 92-01 for Nine Mile Point Unit 1", June 12, 1992.

Manahan, M.P., et.al.,

"Statistical Analysis Methodology for Mechanics of Fracture", Final report to Battelle's Corporate Technology Development Office, 1984.

[MTEB81]

NRC Branch Technical Position MTEB 5-2, "Fracture Toughness Requirements",

Revision 1, July, 1981.

[OD86]

Odette, G.R., Lombrazo, P.M., "The Relation Between Irradiation Hardening and Embrittlement of Pressure Vessel Steels",

Proceedings of the 12th ASTM Symposium on the Effects of Irradiation on Materials, 1986.

[RG1.99]

Regulatory Guide 1.99, Revision 2, "Radiation Embrittlement of Reactor Vessel Materials", May, 1988.

[TEL92]

Telephone conference regarding NMP-1 low USE, NRC staff, NMPC licensing and engineering staff, MPM Research & Consulting, August 22, 1992.

[USE92]

USE'Version 2.0 Code Package for Elastic-Plastic Fracture Mechanics Assessment of Nuclear Reactor Pressure Vessels, MPM Research & Consulting, 1992.

75

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