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| | issue date = 03/15/2007 | | | issue date = 03/15/2007 |
| | title = Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Appendix B, Crack Driving Force and Growth Rate Estimates | | | title = Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Appendix B, Crack Driving Force and Growth Rate Estimates |
| | author name = Ballinger R G, Bullen D B, Latanision R M | | | author name = Ballinger R, Bullen D, Latanision R |
| | author affiliation = Altran Solutions Corp, Exponent Failure Analysis Associates, Exponent, Inc | | | author affiliation = Altran Solutions Corp, Exponent Failure Analysis Associates, Exponent, Inc |
| | addressee name = | | | addressee name = |
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| NASCRAC is a trademark of Exponent, Inc.
| | Appendix B - Crack Driving Force and Growth Rate Estimates Fracture mechanics analysis techniques were applied to estimate crack-tip stress intensity factors (K) and crack growth times for postulated flaws in the Nozzle-3 J-groove weld and adjacent nozzle wall. Calculations were performed using the NASCRAC' Software1, a commercially available, general-purpose fracture mechanics analysis program developed by Exponent for NASA. Weight-function (or influence function) K-solutions in the NASCRAC program calculate K-values as a function of crack size, crack shape, and the stress distribution at the crack location in the un-cracked body. Because the weight-function crack solutions use stress from the un-cracked bode, stresses for K-calculation can be readily obtained from finite element analysis without having to explicitly model cracks. For the Nozzle-3 cracking analysis, the complete bivariate hoop stress distribution through the nozzle wall and weld was obtained from the finite element analysis described in Appendix A. |
| B-1 BN63097.001 B0T0 1106 DB05 Appendix B - Crack Drivin g Force and Growth Rate Estimates Fracture mechanics analysis techniques were applied to estimate crack-tip stress intensity factors (K) and crack growth times for postula ted flaws in the Nozzle-3 J-groove weld and adjacent nozzle wall. Calculations were performed using the NASCRAC Software 1 , a commercially available, general-purpose fracture mechanics analysis program developed by Exponent for NASA. Weight-function (or influe nce function) K-solutions in the NASCRAC program calculate K-values as a function of crack size, crack shape, and the stress distribution at the crack location in the un-cracked body. Because the weight-function crack solutions use stress from the un-cracked bode, stresses for K-ca lculation can be readily obtained from finite element analysis without having to explicitly model cracks. For the Nozzle-3 cracking analysis, the complete bivariate hoop stress distributi on through the nozzle wall and weld was obtained from the finite element analysis described in Appendix A. Two separate influence-function crack models were employed, a four-degree-of-freedom (4-DOF) buried elliptical crack, shown schematically in Figure 1, and a three-degree-of-freedom (3-DOF) semi-elliptical surface crack, shown schematically in Figure 2. Each semi-minor and semi-major axis tip of the buried ellipse or surface semi-ellipse is a degree-of-freedom (DOF) in
| | Two separate influence-function crack models were employed, a four-degree-of-freedom (4-DOF) buried elliptical crack, shown schematically in Figure 1, and a three-degree-of-freedom (3-DOF) semi-elliptical surface crack, shown schematically in Figure 2. Each semi-minor and semi-major axis tip of the buried ellipse or surface semi-ellipse is a degree-of-freedom (DOF) in the influence function models. A separate K and growth rate is calculated for each DOF, or crack tip, so during a simulation a growing crack can change shape based on the relative growth rates at the different crack tips. |
| | Although the final geometry of Crack 1 in CRDM Nozzle 3 and J-groove weld does not lend itself well to idealization with either the buried elliptical crack solution or the surface semi-ellipse, these two crack models can be used to accurately evaluate the growth of smaller cracks representing earlier stages of PWSCC growth in the weld and nozzle wall. Using a high-refinement area integration option in the NASCRAC program, these elliptical crack models can also be used to obtain reasonable and conservative estimates of K for larger crack sizes, even where small regions of the postulated elliptical or semi-elliptical crack pass outside the cracked body, as will be discussed further below. In such cases, zero values of stress are input to the NASCRAC is a trademark of Exponent, Inc. B-1 BN63097.001 B0T0 1106 DB05 |
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| the influence function models. A separate K and growth rate is calculated for each DOF, or crack tip, so during a simulation a growing crack can change shape based on the relative growth rates at the different crack tips. | | program in the areas outside the body, so that there is no contribution to the integrated K results from those areas. This approximation technique typically results in under-prediction of K values because no account is taken of the elevating effect on K of the extra free surfaces intersecting the crack. For example, the K values from the buried elliptical crack model used for growth from the bottom of the weld will be lower (by about 10-12%) than the actual re-entrant corner crack being simulated because the actual crack has two free surfaces, which will elevate K relative to a completely buried crack under the same loading. |
| Although the final geometry of Crack 1 in CRDM Nozzle 3 and J-groove weld does not lend itself well to idealization with either the buried elliptical crack solution or the surface semi-ellipse, these two crack models can be used to accurately evaluate the growth of smaller cracks representing earlier stages of PWSCC growth in the weld a nd nozzle wall. Using a high-refinement area integration option in the NASCRAC program, these elliptical crack models can also be used to obtain reasonable and conservative estimates of K for larger crack sizes, even where small regions of the postulated elliptical or semi-elliptical crack pass outside the cracked body, as will be discussed further below. In su ch cases, zero values of stress are input to the NASCRAC is a trademark of Exponent, Inc.
| | All growth life estimates in the cases presented herein are based on the Davis-Besse Alloy-600 PWSCC crack growth rate2 (CGR) fit. As shown in Figure 3, the EPRI/MRP disposition curve for Alloy-182 weld metal3 falls nearly on top of the Davis-Besse Alloy-600 curve, and in fact, slightly above it, especially at lower crack driving forces. For conservatism in this analysis, the Davis-Besse Alloy-600 CGR relation was used for both nozzle and weld-metal growth simulations. Although the tested Alloy-182 material from Davis-Besse Nozzle 11 exhibited lower than expected growth rates, the cracking experience at Davis-Besse and Oconee demonstrates the high variability in PWSCC cracking. The extent of cracking observed in Nozzles 2 and 3, and particularly in the J-groove weld of Nozzle 3, clearly suggests a greater susceptibility to PWSCC growth than in Nozzle 11. Therefore, the Alloy-600 CGR relation was deemed appropriate for use in simulation of Nozzle-3 weld and nozzle cracking growth. |
| B-2 BN63097.001 B0T0 1106 DB05 program in the areas outside the body, so that there is no contribution to the integrated K results from those areas. This approximation technique typically results in under-prediction of K values because no account is taken of the elev ating effect on K of the extra free surfaces intersecting the crack. For example, the K values from the buried elliptical crack model used for growth from the bottom of the weld will be lower (by about 10-12%) than the actual re-entrant corner crack being simulated because the actual crack has two free surfaces, which will elevate K relative to a completely buried crack under the same loading. All growth life estimates in the cases presen ted herein are based on the Davis-Besse Alloy-600 PWSCC crack growth rate 2 (CGR) fit. As shown in Figure 3, the EPRI/MRP disposition curve for Alloy-182 weld metal 3 falls nearly on top of the Davis-Be sse Alloy-600 curve, and in fact, slightly above it, especially at lower crack drivin g forces. For conservatism in this analysis, the Davis-Besse Alloy-600 CGR relation was used for both nozzle and weld-metal growth simulations. Although the tested Alloy-182 material from Davis-Besse Nozzle 11 exhibited lower than expected growth rates, the cracking experience at Da vis-Besse and Oconee demonstrates the high variability in PWSCC cr acking. The extent of cracking observed in Nozzles 2 and 3, and particularly in the J-groove weld of Nozzle 3, clearly suggests a greater susceptibility to PWSCC growth than in Nozzl e 11. Therefore, the Al loy-600 CGR relation was deemed appropriate for use in simulation of Nozzle-3 weld and nozzle cracking growth.
| | One of the most highly stressed locations in the J-groove weld, based on the finite element analysis results, was at the bottom of the weld close to the OD of the nozzle wall. This location is directly exposed to primary coolant water, and thus would have been a likely spot for PWSCC crack initiation at Nozzle 3. Figure 4 shows the results of a crack-growth simulation that postulated an initial crack, 0.01-inch in radius, located at the bottom of the weld at the nozzle OD. As indicated above, the K-values in this simulation will be low due to the fact that the buried-elliptical crack model does not include free-surface effects on K. Thus, the predicted crack growth rates are expected to be lower than actual, and the time to grow the crack through-wall was shorter than predicted. |
| One of the most highly stressed locations in the J-groove weld, based on the finite element analysis results, was at the bottom of the weld cl ose to the OD of the nozzle wall. This location is directly exposed to primary coolant water, and thus would have been a likely spot for PWSCC crack initiation at Nozzle 3. Fi gure 4 shows the results of a crack-growth simulation that postulated an initial crack, 0.01-inch in radius, located at the bottom of the weld at the nozzle OD. As indicated above, the K-values in this simulation will be low due to the fact that the buried-elliptical crack model does not include free-surface effects on K. Thus, the predicted crack growth rates are expected to be lower than actual, and the time to grow the crack through-wall was shorter than predicted. The general shape of the simulate d crack shown in Figure 4 is consistent with the general shape of cracks in Davis-Besse Nozzles 2 and 3 in that the actual nozzle cracks suggest more rapid NASCRAC is a trademark of Exponent, Inc.
| | The general shape of the simulated crack shown in Figure 4 is consistent with the general shape of cracks in Davis-Besse Nozzles 2 and 3 in that the actual nozzle cracks suggest more rapid NASCRAC is a trademark of Exponent, Inc. B-2 BN63097.001 B0T0 1106 DB05 |
| B-3 BN63097.001 B0T0 1106 DB05 growth in the highly stressed J-groove weld with subsequent growth from the weld into the nozzle wall from the OD. The UT profile of Crack 1 in Nozzle 2 4 , as shown in Figure 5, is a good example of this growth pattern and likely resembles the middle stage of growth of Crack 1 in Nozzle 3.
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| Another crack shape that suggests weld cracking as well as nozzle cracking can be seen in the profile of Crack 4 in Nozzle 3, shown in Figure
| | growth in the highly stressed J-groove weld with subsequent growth from the weld into the nozzle wall from the OD. The UT profile of Crack 1 in Nozzle 24, as shown in Figure 5, is a good example of this growth pattern and likely resembles the middle stage of growth of Crack 1 in Nozzle 3. |
| : 6. Crack 4 in Nozzle 3 appears to have grown from the weld toward the ID of the nozzle; howev er, in this case, another crack appears to have initiated on the ID surface of the nozzle and grown outward toward the larger crack. Two more similar examples of OD and ID initiated cracks growing toward one another can be seen in the UT profiles of Cracks 4 and 10 of Nozzle 2 (see Reference 4) The presence of the larger cracks likely raised the stress at the ID of the nozzle wall above the we ld sufficiently to initiate ID cracks. Based on the crack driving force and growth rate calculated for the postulated crack in Figure 4, the two cracks shown in Figure 6 would likely have grown together (i.e., linked up) in a matter of months, had they not been removed from service in February 2002. The UT examinations could not reliably detect, or "see," cracking in the J-groove welds beyond the OD of the nozzle walls; yet, cracking profiles like those show n in Figure 5 and Figure 6 strongly suggest that the J-groove welds were also cracked, especially in light of the fact that much of the industry data for PWSCC growth in Alloy 182 shows higher CGRs, on average, than in Alloy 600. Figure 7 shows results from a simulation that postulated a long, shallow, axial crack at the highest stress location on the ID surface of the nozzle, which is slightly above the top of the weld. The ID hoop stress in that region from the finite element analysis is 36 ksi under operating conditions. This type of long, shallow crack can develop as a result of link-up of a number of smaller, collinear, ID PWSCC crack initiations. Growth fr om the initial 0.03-inch depth to break-through at the top of the weld is predicted to take just over three years, ignoring any link-up with other cracks. However, the pr ofile of Nozzle-3 Crack 4, shown in Figure 6, clearly indicates how multiple cracks could link up and increase overall crack size in a short period of time, much less than predicted by assuming growth of only a single crack. This is further supported by the analysis results. The ID-crack growth schematic in Figure 7 includes NASCRAC is a trademark of Exponent, Inc.
| | Another crack shape that suggests weld cracking as well as nozzle cracking can be seen in the profile of Crack 4 in Nozzle 3, shown in Figure 6. Crack 4 in Nozzle 3 appears to have grown from the weld toward the ID of the nozzle; however, in this case, another crack appears to have initiated on the ID surface of the nozzle and grown outward toward the larger crack. Two more similar examples of OD and ID initiated cracks growing toward one another can be seen in the UT profiles of Cracks 4 and 10 of Nozzle 2 (see Reference 4) The presence of the larger cracks likely raised the stress at the ID of the nozzle wall above the weld sufficiently to initiate ID cracks. Based on the crack driving force and growth rate calculated for the postulated crack in Figure 4, the two cracks shown in Figure 6 would likely have grown together (i.e., linked up) in a matter of months, had they not been removed from service in February 2002. The UT examinations could not reliably detect, or see, cracking in the J-groove welds beyond the OD of the nozzle walls; yet, cracking profiles like those shown in Figure 5 and Figure 6 strongly suggest that the J-groove welds were also cracked, especially in light of the fact that much of the industry data for PWSCC growth in Alloy 182 shows higher CGRs, on average, than in Alloy 600. |
| B-4 BN63097.001 B0T0 1106 DB05 an overlaid outline of the weld-bottom crack from Figure 4. This comparison indicates that two such cracks, one growing from the highest stress location on the OD and one growing from the highest stress location on the ID, could readily link up to form a single, much larger crack in roughly three years time. The magnitude of K at the upper and lower crack tips of the combined crack would be greater than that of the two i ndividual cracks prior to li nk up, and thus, the crack growth rates would increase after link up. As mentioned previously, the fina l observed profile of Crack 1 in Nozzle 3 does not lend itself well to idealization with either a buried elliptical crack model or a surface semi-elliptical crack model. However, these models can be used to conservatively estimate the crack driving force, and thus the CGR, at the upper tip of Crack 1 in Nozzle 3 as it grew above the top of the J-groove weld. Figure 8 shows cal culated K-values for a series of semi-elliptical cracks of increasing length above the top of the weld. The lower crack tip of each crack was held fixed at 1.2 inches below the bottom of the weld and the crack depth measured from the nozzle ID was held constant at one inch, well into the weld. As was done with the buried el liptical crack simulation of weld-bottom crack growth, the regions of this large crack that extend outside the nozzle wall and weld were assi gned zero values of stress for th e weight-function integration of K. For comparison, the actual fina l size of Crack 1 in Nozzle 3 wa s larger than the largest of these postulated cracks. It extended 1.2 inches above the weld and 1.6 inches below the weld, almost to the end of the nozzle, and deeper into the weld. Several different crack lengths were chosen for analysis to examine the variation in crack driving force with crack length above the top of the weld. The predicted crack driving force, K, at the upper crack tip under operating conditions ranged from 53 ksi in1/2 when the upper tip was even with the top of the weld down to 24 ksi in1/2 for a crack extending to 1.2 inches above the top of the weld. These K values were used to interpolate corresponding crack growth rates for the Davis-Besse Nozzle-3 Alloy 600 using the curve shown in Figure 3. Figure 9 shows PWSCC growth rates for the upper tip of a long axial crack in the nozzle wall based on interpolation in Figure 3 using the calculated crack driving force values shown in Figure 8. Also plotted are the K-values themselves as a function of crack length above the weld.
| | Figure 7 shows results from a simulation that postulated a long, shallow, axial crack at the highest stress location on the ID surface of the nozzle, which is slightly above the top of the weld. The ID hoop stress in that region from the finite element analysis is 36 ksi under operating conditions. This type of long, shallow crack can develop as a result of link-up of a number of smaller, collinear, ID PWSCC crack initiations. Growth from the initial 0.03-inch depth to break-through at the top of the weld is predicted to take just over three years, ignoring any link-up with other cracks. However, the profile of Nozzle-3 Crack 4, shown in Figure 6, clearly indicates how multiple cracks could link up and increase overall crack size in a short period of time, much less than predicted by assuming growth of only a single crack. This is further supported by the analysis results. The ID-crack growth schematic in Figure 7 includes NASCRAC is a trademark of Exponent, Inc. B-3 BN63097.001 B0T0 1106 DB05 |
| We expect the actual K-values and correspond ing CGR at the upper tip were greater than NASCRAC is a trademark of Exponent, Inc.
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| B-5 BN63097.001 B0T0 1106 DB05 predicted for the latter stages of growth, due to the larger size of Nozzle-3 Crack 1 compared to this approximation. This would be the case until late in the development of the head wastage cavity when loss of head material behind the weld likely reduced the residual stress level in the J-groove weld, as was predicted by a DEI simulation
| | an overlaid outline of the weld-bottom crack from Figure 4. This comparison indicates that two such cracks, one growing from the highest stress location on the OD and one growing from the highest stress location on the ID, could readily link up to form a single, much larger crack in roughly three years time. The magnitude of K at the upper and lower crack tips of the combined crack would be greater than that of the two individual cracks prior to link up, and thus, the crack growth rates would increase after link up. |
| : 5. These estimates of growth rate for the upper end of the long axial crack in Nozzle 3 are substantially greater than any prior estimates by others, yet they are consistent with the measured growth rates for Nozzle-3 material, the large size of the observed crack, and the high weld and nozzle stresses predicted by our analysis, as well as similar analyses by others6,7,8. The interpolated crack growth rates shown in Figur e 9 were integrated to obtain estimates of the time to grow the upper crack tip in Nozzle 3 to various heights a bove the top of the weld, thus creating a leakage path. Figure 10 plots growth time in effectiv e full-power years (EFPY) as a function of crack length above the to p of the weld. These results in dicate that all of the growth above the top of the weld of Crack 1 in Nozzle 3 at Davis-Besse likely occurred in less than three EFPY.
| | As mentioned previously, the final observed profile of Crack 1 in Nozzle 3 does not lend itself well to idealization with either a buried elliptical crack model or a surface semi-elliptical crack model. However, these models can be used to conservatively estimate the crack driving force, and thus the CGR, at the upper tip of Crack 1 in Nozzle 3 as it grew above the top of the J-groove weld. Figure 8 shows calculated K-values for a series of semi-elliptical cracks of increasing length above the top of the weld. The lower crack tip of each crack was held fixed at 1.2 inches below the bottom of the weld and the crack depth measured from the nozzle ID was held constant at one inch, well into the weld. As was done with the buried elliptical crack simulation of weld-bottom crack growth, the regions of this large crack that extend outside the nozzle wall and weld were assigned zero values of stress for the weight-function integration of K. For comparison, the actual final size of Crack 1 in Nozzle 3 was larger than the largest of these postulated cracks. It extended 1.2 inches above the weld and 1.6 inches below the weld, almost to the end of the nozzle, and deeper into the weld. Several different crack lengths were chosen for analysis to examine the variation in crack driving force with crack length above the top of the weld. The predicted crack driving force, K, at the upper crack tip under operating conditions ranged from 53 ksi in1/2 when the upper tip was even with the top of the weld down to 24 ksi in1/2 for a crack extending to 1.2 inches above the top of the weld. These K values were used to interpolate corresponding crack growth rates for the Davis-Besse Nozzle-3 Alloy 600 using the curve shown in Figure 3. |
| NASCRAC is a trademark of Exponent, Inc.
| | Figure 9 shows PWSCC growth rates for the upper tip of a long axial crack in the nozzle wall based on interpolation in Figure 3 using the calculated crack driving force values shown in Figure 8. Also plotted are the K-values themselves as a function of crack length above the weld. |
| B-6 BN63097.001 B0T0 1106 DB05 Figure 1. Schematic of four-degree-of-freedom model for a buried elliptical crack from the NASCRAC Software.
| | We expect the actual K-values and corresponding CGR at the upper tip were greater than NASCRAC is a trademark of Exponent, Inc. B-4 BN63097.001 B0T0 1106 DB05 |
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| | predicted for the latter stages of growth, due to the larger size of Nozzle-3 Crack 1 compared to this approximation. This would be the case until late in the development of the head wastage cavity when loss of head material behind the weld likely reduced the residual stress level in the J-groove weld, as was predicted by a DEI simulation5. These estimates of growth rate for the upper end of the long axial crack in Nozzle 3 are substantially greater than any prior estimates by others, yet they are consistent with the measured growth rates for Nozzle-3 material, the large size of the observed crack, and the high weld and nozzle stresses predicted by our analysis, as well as similar analyses by others6,7,8. |
| | The interpolated crack growth rates shown in Figure 9 were integrated to obtain estimates of the time to grow the upper crack tip in Nozzle 3 to various heights above the top of the weld, thus creating a leakage path. Figure 10 plots growth time in effective full-power years (EFPY) as a function of crack length above the top of the weld. These results indicate that all of the growth above the top of the weld of Crack 1 in Nozzle 3 at Davis-Besse likely occurred in less than three EFPY. |
| | NASCRAC is a trademark of Exponent, Inc. B-5 BN63097.001 B0T0 1106 DB05 |
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| | Figure 1. Schematic of four-degree-of-freedom model for a buried elliptical crack from the NASCRAC Software. |
| Figure 2. Schematic of three-degree-of-freedom model of a semi-elliptical surface crack in a cylinder from the NASCRAC Software. | | Figure 2. Schematic of three-degree-of-freedom model of a semi-elliptical surface crack in a cylinder from the NASCRAC Software. |
| NASCRAC is a trademark of Exponent, Inc. | | NASCRAC is a trademark of Exponent, Inc. B-6 BN63097.001 B0T0 1106 DB05 |
| B-7 BN63097.001 B0T0 1106 DB05 Figure 3. Comparison of PWSCC crack growth rate curve fit for Alloy 600 from Davis-Besse Nozzle 3 to EPRI/MRP Alloy-182 disposition curve. | | |
| NASCRAC is a trademark of Exponent, Inc. | | Figure 3. Comparison of PWSCC crack growth rate curve fit for Alloy 600 from Davis-Besse Nozzle 3 to EPRI/MRP Alloy-182 disposition curve. |
| B-8 BN63097.001 B0T0 1106 DB05 Figure 4. Simulation of PWSCC growth from a postulated 0.010-inch initial crack at the bottom of the weld on the nozzle OD. Break-through to nozzle ID predicted in | | NASCRAC is a trademark of Exponent, Inc. B-7 BN63097.001 B0T0 1106 DB05 |
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| | Figure 4. Simulation of PWSCC growth from a postulated 0.010-inch initial crack at the bottom of the weld on the nozzle OD. Break-through to nozzle ID predicted in 3.2 years. |
| | NASCRAC is a trademark of Exponent, Inc. B-8 BN63097.001 B0T0 1106 DB05 |
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| | Figure 5. Proportionally scaled UT profile of Crack 1 in Nozzle 2 based on Framatome UT examination results. [Adapted from Reference 4.] |
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| 3.2 years. | | Figure 6. Proportionally scaled UT profile of Crack 4 in Nozzle 3 based on Framatome UT examination results. [Adapted from Reference 4.] |
| | NASCRAC is a trademark of Exponent, Inc. B-10 BN63097.001 B0T0 1106 DB05 |
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| NASCRAC is a trademark of Exponent, Inc. | | Figure 7. Simulation of growth from a postulated shallow (0.03-inch deep), 0.6-inch long crack at the peak stress location on the nozzle ID to break-through above the top of the weld in 3.2 years. Outline of weld-bottom crack shown in Figure 4 indicates link-up of two such cracks could occur to form a single larger crack. |
| B-9 BN63097.001 B0T0 1106 DB05 Figure 5. Proportionally scaled UT profile of Crack 1 in Nozzle 2 based on Framatome UT examination results. [Adapted from Reference 4.] | | NASCRAC is a trademark of Exponent, Inc. B-11 BN63097.001 B0T0 1106 DB05 |
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| | Figure 8. Calculated K-values for a series of deep, semicircular ID cracks in the nozzle, extending into the weld for estimation of crack growth rates and growth time above the top of the weld. |
| B-10 BN63097.001 B0T0 1106 DB05 Figure 6. Proportionally scaled UT profile of Crack 4 in Nozzle 3 based on Framatome UT examination results. [Adapted from Reference 4.]
| | NASCRAC is a trademark of Exponent, Inc. B-12 BN63097.001 B0T0 1106 DB05 |
| NASCRAC is a trademark of Exponent, Inc.
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| B-11 BN63097.001 B0T0 1106 DB05 Figure 7. Simulation of growth from a postulated shallow (0.03-inch deep), 0.6-inch long crack at the peak stress location on the nozzle ID to break-through above the top of the weld in 3.2 years. Outline of weld-bottom crack shown in Figure 4 indicates link-up of two such cracks could occur to form a single larger crack.
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| NASCRAC is a trademark of Exponent, Inc. | |
| B-12 BN63097.001 B0T0 1106 DB05 Figure 8. Calculated K-values for a series of deep, semicircular ID cracks in the nozzle, extending into the weld for estimation of crack growth rates and growth time | |
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| above the top of the weld. | | Figure 9. Approximate K-values and corresponding PWSCC growth rates for postulated long ID cracks in the nozzle, extending from 1.2 inches below the weld to the indicated length above the weld, as shown in Figure 8. |
| | NASCRAC is a trademark of Exponent, Inc. B-13 BN63097.001 B0T0 1106 DB05 |
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| NASCRAC is a trademark of Exponent, Inc. | | Figure 10. Approximate time in effective full-power years to grow the upper tip of the long axial crack in Nozzle 3 to various lengths above the top of the weld. |
| B-13 BN63097.001 B0T0 1106 DB05 Figure 9. Approximate K-values and corresponding PWSCC growth rates for postulated long ID cracks in the nozzle, extending from 1.2 inches below the weld to the indicated length above the weld, as shown in Figure 8. | | NASCRAC is a trademark of Exponent, Inc. B-14 BN63097.001 B0T0 1106 DB05 |
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| | References |
| B-14 BN63097.001 B0T0 1106 DB05 Figure 10. Approximate time in effective full-power years to grow the upper tip of the long axial crack in Nozzle 3 to various lengths above the top of the weld.
| | : 1. NASCRAC, NASA Crack Analysis Code, Version 3.2, Exponent, Inc., 1999. |
| NASCRAC is a trademark of Exponent, Inc.
| | : 2. B. Alexandreanu et al., Crack Growth Rates in a PWR Environment of Nickel Alloys from the Davis-Besse and V.C. Summer Power Plants, NUREG/CR-6921, U.S. Nuclear Regulatory Commission, November 2006, at Page 68. |
| B-15 BN63097.001 B0T0 1106 DB05 References
| | 3 Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82, 182, and 132 Welds (MRP-115), EPRI TR-1006696, Electric Power Research Institute, Palo Alto, CA, November 2004, at Page 4-4. |
| : 1. "NASCRAC, NASA Crack Analysis C ode," Version 3.2, Exponent, Inc., 1999. 2. B. Alexandreanu et al., "Crack Growth Rates in a PWR Environment of Nickel Alloys from the Davis-Besse and V.C. Summer Po wer Plants," NUREG/CR-6921, U.S. Nuclear Regulatory Commission, November 2006, at Page 68. 3 "Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82, 182, and 132 Welds (MRP-115)," EPRI TR-1006696, Electric Power Research Institute, Palo Alto, CA, November 2004, at Page 4-4. 4. M. Hacker, "Davis-Besse CRDM Crack Profiles," Framatome ANP Engineering Information Record No. 51-5018376-00, May 13, 2002. 5 J. Broussard, "Davis Besse CRDM Nozzle Crack Opening Displacement Analysis," | | : 4. M. Hacker, Davis-Besse CRDM Crack Profiles, Framatome ANP Engineering Information Record No. 51-5018376-00, May 13, 2002. |
| Calculation C-5509-00-7, Revision 0, Dominion Engineering, Inc., March 19, 2002, at Page 3 of 7. 6 "Safety Evaluation for B&W-Design Reactor Vessel Head Control Rod Drive Mechanism Nozzle Cracking," BAW-10190P, B&W Nu clear Technologies, May 1993. 7 J. Broussard and D. Gross, "Welding Residua l and Operating Stress Analysis of RPV Top and Bottom Head Nozzles," Proceedings of the Conference on Vessel Penetration Inspection, Crack Growth and Repair, NUREG/CP-0191, U.S. Nu clear Regulatory Commission, September 2005. 8 D. Rudland et al., "Analysis of Weld Residual Stresses and Circumferential Through-Wall Crack K-solutions for CRDM Nozzles," Pr oceedings of the Conference on Vessel Penetration Inspection, Crack Growth and Repair, NUREG/CP-0191, U.S. Nuclear Regulatory Commission, September 2005.}} | | 5 J. Broussard, Davis Besse CRDM Nozzle Crack Opening Displacement Analysis, Calculation C-5509-00-7, Revision 0, Dominion Engineering, Inc., March 19, 2002, at Page 3 of 7. |
| | 6 Safety Evaluation for B&W-Design Reactor Vessel Head Control Rod Drive Mechanism Nozzle Cracking, BAW-10190P, B&W Nuclear Technologies, May 1993. |
| | 7 J. Broussard and D. Gross, Welding Residual and Operating Stress Analysis of RPV Top and Bottom Head Nozzles, Proceedings of the Conference on Vessel Penetration Inspection, Crack Growth and Repair, NUREG/CP-0191, U.S. Nuclear Regulatory Commission, September 2005. |
| | 8 D. Rudland et al., Analysis of Weld Residual Stresses and Circumferential Through-Wall Crack K-solutions for CRDM Nozzles, Proceedings of the Conference on Vessel Penetration Inspection, Crack Growth and Repair, NUREG/CP-0191, U.S. Nuclear Regulatory Commission, September 2005. |
| | NASCRAC is a trademark of Exponent, Inc. B-15 BN63097.001 B0T0 1106 DB05}} |
|
|---|
Category:Graphics incl Charts and Tables
MONTHYEARL-24-024, Annual 10 CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models2024-06-19019 June 2024
Annual 10 CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models
ML20142A3972020-05-0505 May 2020
Annual Radiological Environmental Operating Report, Figure 32, Wind Rose Annual Average 10M
ML20142A3982020-05-0505 May 2020
Annual Radiological Environmental Operating Report, Figure 31, Wind Riose Annual Average 75M
ML20142A3992020-05-0505 May 2020
Annual Radiological Environmental Operating Report, Figure 30, Wind Rose Annual Average 100M
ML16056A1392016-03-11011 March 2016
Correction to the U.S. Nuclear Regulatory Commission Analysis of Licensees' Decommissioning Funding Status Reports
ML15239B2122015-09-0303 September 2015
Interim Staff Response to Reevaluated Flood Hazards Submitted in Response to 10 CFR 50.54(f) Information Request - Flood-Causing Mechanism Reevaluation
ML15238B8652015-09-0303 September 2015
FHRR MSFHI Tables 1 and 2
ML14307B7072014-12-10010 December 2014
Supplemental Information Related to Development of Seismic Risk Evaluations for Information Request Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Seismic Hazard Reevaluations for Recommendation 2.1 of the Near-T
L-13-257, Notification of Completion of a License Renewal Commitment Related to the Review of License Renewal Application TAC No. ME4640) and License Renewal Application Amendment No. 45)2013-07-23023 July 2013
Notification of Completion of a License Renewal Commitment Related to the Review of License Renewal Application TAC No. ME4640) and License Renewal Application Amendment No. 45)
ML12167A2622012-05-29029 May 2012
Enclosure - Davis-Besse 17RFO License Condition 2.C(7) SG Circumferential Crack Report
ML1214500142012-05-23023 May 2012
NFPA 805 LAR Status Matrix - May 2012
ML1015201172010-05-28028 May 2010
Nozzle 4 - 52M Deposit Depth
ML1005396232010-02-22022 February 2010
Lessons Learned Task Force Action Plan Regarding Stress Corrosion Cracking Dec 2009 (Final Update)
ML0824902892008-10-0202 October 2008
ITSB Draft L, to Davis-Besse Amendment Conversion Improved Technical Specifications with Beyond Scope Issues
ML0824903002008-10-0202 October 2008
ITSB Draft R, to Davis-Besse Amendment Conversion Improved Technical Specifications with Beyond Scope Issues
ML0824902952008-10-0202 October 2008
ITSB Draft M, to Davis-Besse Amendment Conversion Improved Technical Specifications with Beyond Scope Issues
ML0824902752008-10-0202 October 2008
Draft a, Attachment to Davis Besse Amendment Conversion Improved Technical Specifications with Beyond Scope Issues
ML0824902802008-10-0202 October 2008
ITSB Draft La, to Davis Besse Amendment Conversion Improved Technical Specifications with Beyond Scope Issues
L-08-094, Response to Request for Additional Information Regarding Measurement Uncertainty Recapture Power Uprate Amendment Application2008-03-12012 March 2008
Response to Request for Additional Information Regarding Measurement Uncertainty Recapture Power Uprate Amendment Application
ML0727405102008-02-11011 February 2008
Lltf Action Plan Feb 2008 Update - Public
ML0803700812008-02-0101 February 2008
Lltf Status of Recommendations February 2008
ML0728203072007-10-11011 October 2007
Electronic Distribtion Initiative Letter, Licensee List, Electronic Distribution Input Information, Division Plant Mailing Lists
ML0708602822007-03-15015 March 2007
Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Appendix B, Crack Driving Force and Growth Rate Estimates
ML0708602812007-03-15015 March 2007
Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Appendix a, Finite Element Stress Analysis of Davis-Besse CRDM Nozzle 3 Penetration
ML0708602712007-03-15015 March 2007
Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Section 8. Stress Analysis and Crack Growth Rates for Davis-Besse CRDM Nozzles 2 and 3
ML0708602682007-03-15015 March 2007
Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Section 7. FENOC/Davis-Besse Response to CRDM Cracking and Boric Acid Corrosion Issues
ML0708602642007-03-15015 March 2007
Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Section 6. Boric Acid Wastage of Carbon Steel Components in Us PWR Plants
ML0708602612007-03-15015 March 2007
Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Section 5. Worldwide Industry Response to CRDM and Other Alloy 600 Nozzle Cracking
ML0708602532007-03-15015 March 2007
Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Section 3. Background
ML0702603952007-01-31031 January 2007
Summary of Conference Telephone Call Regarding the Spring 2006 Steam Generator Inspections - Handouts
ML0618002582006-06-27027 June 2006
Closure of Davis-Besse Operational Improvement Plan
ML0611401302006-03-16016 March 2006
Ltr Fm J. Gutierrez, Morgan Lewis to S. Brock Requesting to Withhold Materials from Public Disclosure Which Was Submitted by FENOC - Affidavits of Terry Young and Warren Bilanin
ML0525707982005-09-12012 September 2005
Documentation of Completed Post-Restart Process Plan for Transition of Davis-Besse from the IMC 0350 Oversight Process to the Reactor Oversight Program (ROP)
ML0523801412005-08-31031 August 2005
Status of Davis-Besse Lessons Learned Task Force Recommendations - Last Update: August 31, 2005
ML0411301992004-04-21021 April 2004
Oversight Panel Final Restart Checklist Public Release Memo
ML0414503382004-02-13013 February 2004
Oversight Panel Open Action Item List
ML0414503372004-02-13013 February 2004
IMC 0350 Panel Process Plan
ML0414503262004-02-13013 February 2004
Restart Action Matrix - Open Items Only
ML0308000432003-01-0101 January 2003
Firstenergy Nuclear Operating Company, NRC Allegations and Employee Concerns Program Contact Trends, January 2002 - January 2003
ML0224601492002-08-29029 August 2002
Undated Data Chart, CDF, LERF, Rem
ML0224601482002-08-29029 August 2002
Heat 69 Crack Growth - Bounding Weibull with 1.5 Shape Facto with Handwritten Notes
ML0224601422002-08-29029 August 2002
Chart, Long-Term Results for Integrated Model with Handwritten Notes
ML0224003452002-08-27027 August 2002
Failure Frequency Curve for Davis-Besse Conditions
ML0224003402002-08-27027 August 2002
Draft Graphs for Flaw Curves and Stress Intensity Factors
ML0530703682002-03-13013 March 2002
Timeline of Key Events Related to Reactor Vessel Head Boric Acid Wastage Rev.3, 3-13-02
ML0530704022001-04-20020 April 2001
Normal Sump Pump Samples
2024-06-19
[Table view]
Category:Report
MONTHYEARL-23-214, Submittal of Relief Request for Impractical American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI Examination Requirements2024-06-0505 June 2024
Submittal of Relief Request for Impractical American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI Examination Requirements
L-23-188, Energy Harbor Nuclear Corp., Supplement to Application for Order Consenting to Transfer of Licenses and Conforming License Amendments2023-08-0707 August 2023
Energy Harbor Nuclear Corp., Supplement to Application for Order Consenting to Transfer of Licenses and Conforming License Amendments
L-22-253, Submittal of Pressure and Temperature Limits Report, Revision 52023-01-10010 January 2023
Submittal of Pressure and Temperature Limits Report, Revision 5
L-22-211, Technical Specification 5.6.6 Steam Generator Tube Inspection 180-Day Report2022-09-29029 September 2022
Technical Specification 5.6.6 Steam Generator Tube Inspection 180-Day Report
L-22-216, Submittal of Pressure and Temperature Limits Report. Revision 42022-09-27027 September 2022
Submittal of Pressure and Temperature Limits Report. Revision 4
L-22-149, Post Accident Monitoring Report2022-06-23023 June 2022
Post Accident Monitoring Report
ML22202A4362022-04-0808 April 2022
Enclosure F: Updated Inputs to 52 EFPY P-T Operating Curves
ML22202A4372022-03-0202 March 2022
Enclosure G: Framatome Inc. Document 86-9344713-000, Davis-Besse Reactor Vessel Embrittlement Fluence Reconciliation Through 60 Years
IR 05000346/20210902021-12-16016 December 2021
Reissue Davis-Besse NRC Inspection Report (05000346/2021090) Preliminary White Finding
ML21322A2892021-12-0909 December 2021
Approval of Plant-Specific Analysis of Certain Reactor Vessel Internal Components in Accordance with License Renewal Commitment No. 53
ML20302A3022020-09-25025 September 2020
1 to Technical Requirements Manual
ML19255H0992019-10-10010 October 2019
Staff Assessment of Flooding Focused Evaluation
L-19-189, 54010-CALC-01, Davis-Besse Nuclear Power Station: Evaluation of Risk Significance of Permanent ILRT Extension.2019-07-29029 July 2019
54010-CALC-01, Davis-Besse Nuclear Power Station: Evaluation of Risk Significance of Permanent ILRT Extension.
ML22262A1522019-05-0101 May 2019
Framatome Inc., Document ANP-2718NP, Revision 007, Appendix G Pressure-Temperature Limits for 52 EFPY for the Davis-Besse Nuclear Power Station
ML22202A4332019-04-30030 April 2019
Enclosure C: Framatome ANP-2718NP, Rev. 7, Appendix G Pressure-Temperature Limits for 52 EFPY for the Davis-Besse Nuclear Power Station
L-18-108, Request to Extend Enforcement Discretion Provided in Enforcement Guidance Memorandum 15-002 for Tornado-Generated Missile Protection Non-Conformance Identified in Response to Regulatory Issue Summary 2015-06, Tornado Missile....2018-04-12012 April 2018
Request to Extend Enforcement Discretion Provided in Enforcement Guidance Memorandum 15-002 for Tornado-Generated Missile Protection Non-Conformance Identified in Response to Regulatory Issue Summary 2015-06, Tornado Missile....
ML18149A2812018-02-16016 February 2018
2017 ATI Environmental Inc. Midwest Laboratory Radiological Environmental Monitoring Program
L-17-270, Notification of Emergency Core Cooling System (ECCS) Evaluation Model Change Pursuant to 10 CFR 50.462017-09-0101 September 2017
Notification of Emergency Core Cooling System (ECCS) Evaluation Model Change Pursuant to 10 CFR 50.46
ML17086A0322017-03-31031 March 2017
Enclosure B to L-17-105, Areva Report ANP-3542NP, Revision 1, Time-Limited Aging Analysis (TLAA) Regarding Reactor Vessel Internals Loss of Ductility at 60 Years
L-17-088, Independent Spent Fuel Storage Installation Changes, Tests and Experiments2017-03-27027 March 2017
Independent Spent Fuel Storage Installation Changes, Tests and Experiments
ML17026A0082016-12-31031 December 2016
Areva Report ANP-3542NP, Time-Limited Aging Analysis (TLAA) Regarding Reactor Vessel Internals Loss of Ductility for Davis-Besse Nuclear Power Station, Unit No. 1 at 60 Years (Non Proprietary)
L-16-229, Submittal of Pressure and Temperature Limits Report, Revision 32016-07-28028 July 2016
Submittal of Pressure and Temperature Limits Report, Revision 3
L-16-148, Fatigue Monitoring Program Evaluation of Reactor Coolant Pressure Boundary Components for Effects of the Reactor Coolant Environment on Fatigue Usage (I.E., Environmentally-Assisted Fatigue)2016-04-21021 April 2016
Fatigue Monitoring Program Evaluation of Reactor Coolant Pressure Boundary Components for Effects of the Reactor Coolant Environment on Fatigue Usage (I.E., Environmentally-Assisted Fatigue)
L-15-288, Response to NRC Letter. Request for Information, Per 10 CFR 50.54(f) Regarding Recommendations 2.1. 2.3. and 9.3. of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident2015-10-0202 October 2015
Response to NRC Letter. Request for Information, Per 10 CFR 50.54(f) Regarding Recommendations 2.1. 2.3. and 9.3. of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident
ML15230A2892015-08-25025 August 2015
Staff Assessment of Information Provided Pursuant to Title 10 of the Code of Federal Regulations Part 50 Seismic Hazard Reevaluations for Recommendation 2.1 of the Near-Term Task Force Review
L-14-401, First Energy Nuclear Operating Company (FENOC) Expedited Seismic Evaluation Process (ESEP) Reports Response to NRC Request for Information Pursuant to 10 CFR50.54(f) Regarding Recommendation.1 of the Near-Term Task Force (NTTF) Review of In2014-12-19019 December 2014
First Energy Nuclear Operating Company (FENOC) Expedited Seismic Evaluation Process (ESEP) Reports Response to NRC Request for Information Pursuant to 10 CFR50.54(f) Regarding Recommendation.1 of the Near-Term Task Force (NTTF) Review of In
ML14353A0602014-11-0303 November 2014
2734296-R-010, Rev. 0, Expedited Seismic Evaluation Process (ESEP) Report Davis-Besse Nuclear Power Station
L-14-289, Pressure and Temperature Limits Report. Revision 22014-09-22022 September 2014
Pressure and Temperature Limits Report. Revision 2
L-14-259, Firstenergy Nuclear Operating Company'S (Fenoc'S) Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051)2014-08-28028 August 2014
Firstenergy Nuclear Operating Company'S (Fenoc'S) Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Reliable Spent Fuel Pool Instrumentation (Order Number EA-12-051)
ML14141A5252014-06-30030 June 2014
Staff Assessment of the Flooding Walkdown Report Supporting Implementation of Near-Term Task Force Recommendation 2.3 Related to the Fukushima DAI-ICHI Nuclear Power Plant Accident
L-14-167, Report of Facility Changes, Tests and Experiments for the Period Ending May 26, 20142014-06-18018 June 2014
Report of Facility Changes, Tests and Experiments for the Period Ending May 26, 2014
ML14134A5172014-05-30030 May 2014
Staff Assessment of the Seismic Walkdown Report Supporting Implementation of Near-Term Task Force Recommendation 2.3 Related to the Fukushima DAI-ICHI Nuclear Power Plant Accident
L-14-148, CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models2014-05-19019 May 2014
CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models
ML14112A3152014-04-21021 April 2014
Review of Draft Plant-Specific Supplement 52 to the Generic Environmental Impact Statement for License Renewal of Nuclear Plants Regarding
L-14-104, Firstenergy Nuclear Operating Co. Response to NRC Request for Information Pursuant to 10 CFR 50.54 (F) Regarding the Flooding Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident2014-03-11011 March 2014
Firstenergy Nuclear Operating Co. Response to NRC Request for Information Pursuant to 10 CFR 50.54 (F) Regarding the Flooding Aspects of Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident
ML14007A6702014-02-21021 February 2014
Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-12-049 (Mitigation Strategies)
ML14042A2942014-02-19019 February 2014
Mega-Tech Services, LLC, Technical Evaluation Report Regarding the Overall Integrated Plan for Davis-Besse Nuclear Power Station, TAC No.: MF0961
ML13340A1592013-11-26026 November 2013
Davis-Besse Nuclear Power Station Near-Term Task Force Recommendation 2.3 Seismic Walkdown Report Revision 1, Appendix a
ML13340A1472013-11-26026 November 2013
Davis-Besse Nuclear Power Station & Perry Nuclear Power Plant - Response to RAI Associated with Seismic Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident (TAC Nos. MF0116 & MF0
ML13340A1632013-10-0909 October 2013
Davis-Besse Nuclear Power Station Near-Term Task Force Recommendation 2.3 Seismic Walkdown Report Revision 1, Appendix C to Appendix G
ML13340A1622013-10-0909 October 2013
Davis-Besse Nuclear Power Station Near-Term Task Force Recommendation 2.3 Seismic Walkdown Report Revision 1, Appendix B (2 of 2)
ML13340A1602013-10-0909 October 2013
Davis-Besse Nuclear Power Station Near-Term Task Force Recommendation 2.3 Seismic Walkdown Report Revision 1, Appendix B (1 of 2)
ML13340A1582013-10-0909 October 2013
Davis-Besse Nuclear Power Station Near-Term Task Force Recommendation 2.3 Seismic Walkdown Report Revision 1
L-13-154, CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models2013-05-28028 May 2013
CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models
L-13-157, Generic Safety Issue 191 Resolution Plan2013-05-15015 May 2013
Generic Safety Issue 191 Resolution Plan
ML13009A3752012-12-12012 December 2012
Enclosure B to L-12-444, Calculation No. 32-9195651-000, Equivalent Margins Assessment of Davis-Besse Transition Welds for 52 EFPY - Non-Proprietary.
L-12-347, FENOC Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Flooding Aspects of Recommendation 2.3 of Near-Term Task Force Review of Insights from Fukushima Dai-ichi Accident2012-11-27027 November 2012
FENOC Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding Flooding Aspects of Recommendation 2.3 of Near-Term Task Force Review of Insights from Fukushima Dai-ichi Accident
ML13135A2442012-08-10010 August 2012
Near-Term Task Force Recommendation 2.3 Seismic Walkdown Report, Appendix B - Seismic Walkdown Checklists (Swcs), Sheet 1 of 379 Through Sheet 201 of 379
ML13135A2432012-08-10010 August 2012
Near-Term Task Force Recommendation 2.3 Seismic Walkdown Report, Appendix a - Resumes and Qualifications
ML13135A2422012-08-10010 August 2012
Near-Term Task Force Recommendation 2.3 Seismic Walkdown Report, Cover Through Page 176
2024-06-05
[Table view]
Category:Technical
MONTHYEARL-23-214, Submittal of Relief Request for Impractical American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI Examination Requirements2024-06-0505 June 2024
Submittal of Relief Request for Impractical American Society of Mechanical Engineers Boiler and Pressure Vessel Code Section XI Examination Requirements
L-22-253, Submittal of Pressure and Temperature Limits Report, Revision 52023-01-10010 January 2023
Submittal of Pressure and Temperature Limits Report, Revision 5
L-22-211, Technical Specification 5.6.6 Steam Generator Tube Inspection 180-Day Report2022-09-29029 September 2022
Technical Specification 5.6.6 Steam Generator Tube Inspection 180-Day Report
L-22-216, Submittal of Pressure and Temperature Limits Report. Revision 42022-09-27027 September 2022
Submittal of Pressure and Temperature Limits Report. Revision 4
L-22-149, Post Accident Monitoring Report2022-06-23023 June 2022
Post Accident Monitoring Report
ML22202A4362022-04-0808 April 2022
Enclosure F: Updated Inputs to 52 EFPY P-T Operating Curves
ML22202A4372022-03-0202 March 2022
Enclosure G: Framatome Inc. Document 86-9344713-000, Davis-Besse Reactor Vessel Embrittlement Fluence Reconciliation Through 60 Years
ML21322A2892021-12-0909 December 2021
Approval of Plant-Specific Analysis of Certain Reactor Vessel Internal Components in Accordance with License Renewal Commitment No. 53
ML20302A3022020-09-25025 September 2020
1 to Technical Requirements Manual
ML19255H0992019-10-10010 October 2019
Staff Assessment of Flooding Focused Evaluation
L-19-189, 54010-CALC-01, Davis-Besse Nuclear Power Station: Evaluation of Risk Significance of Permanent ILRT Extension.2019-07-29029 July 2019
54010-CALC-01, Davis-Besse Nuclear Power Station: Evaluation of Risk Significance of Permanent ILRT Extension.
ML22262A1522019-05-0101 May 2019
Framatome Inc., Document ANP-2718NP, Revision 007, Appendix G Pressure-Temperature Limits for 52 EFPY for the Davis-Besse Nuclear Power Station
ML22202A4332019-04-30030 April 2019
Enclosure C: Framatome ANP-2718NP, Rev. 7, Appendix G Pressure-Temperature Limits for 52 EFPY for the Davis-Besse Nuclear Power Station
ML18149A2812018-02-16016 February 2018
2017 ATI Environmental Inc. Midwest Laboratory Radiological Environmental Monitoring Program
L-17-270, Notification of Emergency Core Cooling System (ECCS) Evaluation Model Change Pursuant to 10 CFR 50.462017-09-0101 September 2017
Notification of Emergency Core Cooling System (ECCS) Evaluation Model Change Pursuant to 10 CFR 50.46
ML17086A0322017-03-31031 March 2017
Enclosure B to L-17-105, Areva Report ANP-3542NP, Revision 1, Time-Limited Aging Analysis (TLAA) Regarding Reactor Vessel Internals Loss of Ductility at 60 Years
ML17026A0082016-12-31031 December 2016
Areva Report ANP-3542NP, Time-Limited Aging Analysis (TLAA) Regarding Reactor Vessel Internals Loss of Ductility for Davis-Besse Nuclear Power Station, Unit No. 1 at 60 Years (Non Proprietary)
L-16-229, Submittal of Pressure and Temperature Limits Report, Revision 32016-07-28028 July 2016
Submittal of Pressure and Temperature Limits Report, Revision 3
L-15-288, Response to NRC Letter. Request for Information, Per 10 CFR 50.54(f) Regarding Recommendations 2.1. 2.3. and 9.3. of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident2015-10-0202 October 2015
Response to NRC Letter. Request for Information, Per 10 CFR 50.54(f) Regarding Recommendations 2.1. 2.3. and 9.3. of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident
L-14-289, Pressure and Temperature Limits Report. Revision 22014-09-22022 September 2014
Pressure and Temperature Limits Report. Revision 2
ML14134A5172014-05-30030 May 2014
Staff Assessment of the Seismic Walkdown Report Supporting Implementation of Near-Term Task Force Recommendation 2.3 Related to the Fukushima DAI-ICHI Nuclear Power Plant Accident
L-14-148, CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models2014-05-19019 May 2014
CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models
ML14112A3152014-04-21021 April 2014
Review of Draft Plant-Specific Supplement 52 to the Generic Environmental Impact Statement for License Renewal of Nuclear Plants Regarding
ML14007A6702014-02-21021 February 2014
Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-12-049 (Mitigation Strategies)
ML14042A2942014-02-19019 February 2014
Mega-Tech Services, LLC, Technical Evaluation Report Regarding the Overall Integrated Plan for Davis-Besse Nuclear Power Station, TAC No.: MF0961
L-13-154, CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models2013-05-28028 May 2013
CFR 50.46 Report of Changes to or Errors in Emergency Core Cooling System Evaluation Models
ML13009A3752012-12-12012 December 2012
Enclosure B to L-12-444, Calculation No. 32-9195651-000, Equivalent Margins Assessment of Davis-Besse Transition Welds for 52 EFPY - Non-Proprietary.
ML13008A0612012-08-10010 August 2012
Davis-Besse Near-Term Task Force Recommendation 2.3 Seismic Walkdown Report, Appendix C, Area Walk-By Checklists, Sheet 21 of 139 Through End
L-15-328, Enclosure B, Bechtel Report No. 25593-000-G83-GEG-00016-000, Effect of Laminar Cracks on Splice Capacity of No. 11 Bars Based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building. Part 7 of 72012-07-30030 July 2012
Enclosure B, Bechtel Report No. 25593-000-G83-GEG-00016-000, Effect of Laminar Cracks on Splice Capacity of No. 11 Bars Based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building. Part 7 of 7
ML15299A1502012-07-30030 July 2012
Enclosure B, Bechtel Report No. 25593-000-G83-GEG-00016-000, Effect of Laminar Cracks on Splice Capacity of No. 11 Bars Based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building. Part 6 of 7
ML15299A1492012-07-30030 July 2012
Enclosure B, Bechtel Report No. 25593-000-G83-GEG-00016-000, Effect of Laminar Cracks on Splice Capacity of No. 11 Bars Based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building. Part 5 of 7
ML15299A1482012-07-30030 July 2012
Enclosure B, Bechtel Report No. 25593-000-G83-GEG-00016-000, Effect of Laminar Cracks on Splice Capacity of No. 11 Bars Based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building. Part 4 of 7
ML15299A1472012-07-30030 July 2012
Enclosure B, Bechtel Report No. 25593-000-G83-GEG-00016-000, Effect of Laminar Cracks on Splice Capacity of No. 11 Bars Based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building. Part 3 of 7
ML15299A1462012-07-30030 July 2012
Enclosure B, Bechtel Report No. 25593-000-G83-GEG-00016-000, Effect of Laminar Cracks on Splice Capacity of No. 11 Bars Based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building. Part 2 of 7
ML15299A1442012-07-30030 July 2012
Enclosure B, Bechtel Report No. 25593-000-G83-GEG-00016-000, Effect of Laminar Cracks on Splice Capacity of No. 11 Bars Based on Testing Conducted at Purdue University and University of Kansas for Davis-Besse Shield Building. Part 1 of 7
ML12209A2602012-07-26026 July 2012
Attachment 31, Fauske & Associates, Inc. Technical Bulletin No. 1295-1, BWR MSIV Leakage Assessment: NUREG-1465 Vs. MAAP 4.0.2
ML1017400422010-06-0404 June 2010
0800368.407, Rev. 0, Summary of Design and Analysis of Weld Overlays for Reactor Coolant Pump Suction and Discharge, Cold Leg Drain, and Core Flood Nozzle Dissimilar Metal Welds for Alloy 600 Primary Water Stress Corrosion Cracking Mitigati
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0800368.404, Revision 1, Leak-Before-Break Evaluation of Reactor Coolant Pump Suction and Discharge Nozzle Weld Overlays for Davis-Besse Nuclear Power Station, Enclosure B
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Review and Analysis of the Davis-Besse March 2002 Reactor Pressure Vessel Head Wastage Event, Appendix C, Cfd Analysis
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Appendix B Crack Driving Force and Growth Rate Estimates
Appendix B - Crack Driving Force and Growth Rate Estimates Fracture mechanics analysis techniques were applied to estimate crack-tip stress intensity factors (K) and crack growth times for postulated flaws in the Nozzle-3 J-groove weld and adjacent nozzle wall. Calculations were performed using the NASCRAC' Software1, a commercially available, general-purpose fracture mechanics analysis program developed by Exponent for NASA. Weight-function (or influence function) K-solutions in the NASCRAC program calculate K-values as a function of crack size, crack shape, and the stress distribution at the crack location in the un-cracked body. Because the weight-function crack solutions use stress from the un-cracked bode, stresses for K-calculation can be readily obtained from finite element analysis without having to explicitly model cracks. For the Nozzle-3 cracking analysis, the complete bivariate hoop stress distribution through the nozzle wall and weld was obtained from the finite element analysis described in Appendix A.
Two separate influence-function crack models were employed, a four-degree-of-freedom (4-DOF) buried elliptical crack, shown schematically in Figure 1, and a three-degree-of-freedom (3-DOF) semi-elliptical surface crack, shown schematically in Figure 2. Each semi-minor and semi-major axis tip of the buried ellipse or surface semi-ellipse is a degree-of-freedom (DOF) in the influence function models. A separate K and growth rate is calculated for each DOF, or crack tip, so during a simulation a growing crack can change shape based on the relative growth rates at the different crack tips.
Although the final geometry of Crack 1 in CRDM Nozzle 3 and J-groove weld does not lend itself well to idealization with either the buried elliptical crack solution or the surface semi-ellipse, these two crack models can be used to accurately evaluate the growth of smaller cracks representing earlier stages of PWSCC growth in the weld and nozzle wall. Using a high-refinement area integration option in the NASCRAC program, these elliptical crack models can also be used to obtain reasonable and conservative estimates of K for larger crack sizes, even where small regions of the postulated elliptical or semi-elliptical crack pass outside the cracked body, as will be discussed further below. In such cases, zero values of stress are input to the NASCRAC is a trademark of Exponent, Inc. B-1 BN63097.001 B0T0 1106 DB05
program in the areas outside the body, so that there is no contribution to the integrated K results from those areas. This approximation technique typically results in under-prediction of K values because no account is taken of the elevating effect on K of the extra free surfaces intersecting the crack. For example, the K values from the buried elliptical crack model used for growth from the bottom of the weld will be lower (by about 10-12%) than the actual re-entrant corner crack being simulated because the actual crack has two free surfaces, which will elevate K relative to a completely buried crack under the same loading.
All growth life estimates in the cases presented herein are based on the Davis-Besse Alloy-600 PWSCC crack growth rate2 (CGR) fit. As shown in Figure 3, the EPRI/MRP disposition curve for Alloy-182 weld metal3 falls nearly on top of the Davis-Besse Alloy-600 curve, and in fact, slightly above it, especially at lower crack driving forces. For conservatism in this analysis, the Davis-Besse Alloy-600 CGR relation was used for both nozzle and weld-metal growth simulations. Although the tested Alloy-182 material from Davis-Besse Nozzle 11 exhibited lower than expected growth rates, the cracking experience at Davis-Besse and Oconee demonstrates the high variability in PWSCC cracking. The extent of cracking observed in Nozzles 2 and 3, and particularly in the J-groove weld of Nozzle 3, clearly suggests a greater susceptibility to PWSCC growth than in Nozzle 11. Therefore, the Alloy-600 CGR relation was deemed appropriate for use in simulation of Nozzle-3 weld and nozzle cracking growth.
One of the most highly stressed locations in the J-groove weld, based on the finite element analysis results, was at the bottom of the weld close to the OD of the nozzle wall. This location is directly exposed to primary coolant water, and thus would have been a likely spot for PWSCC crack initiation at Nozzle 3. Figure 4 shows the results of a crack-growth simulation that postulated an initial crack, 0.01-inch in radius, located at the bottom of the weld at the nozzle OD. As indicated above, the K-values in this simulation will be low due to the fact that the buried-elliptical crack model does not include free-surface effects on K. Thus, the predicted crack growth rates are expected to be lower than actual, and the time to grow the crack through-wall was shorter than predicted.
The general shape of the simulated crack shown in Figure 4 is consistent with the general shape of cracks in Davis-Besse Nozzles 2 and 3 in that the actual nozzle cracks suggest more rapid NASCRAC is a trademark of Exponent, Inc. B-2 BN63097.001 B0T0 1106 DB05
growth in the highly stressed J-groove weld with subsequent growth from the weld into the nozzle wall from the OD. The UT profile of Crack 1 in Nozzle 24, as shown in Figure 5, is a good example of this growth pattern and likely resembles the middle stage of growth of Crack 1 in Nozzle 3.
Another crack shape that suggests weld cracking as well as nozzle cracking can be seen in the profile of Crack 4 in Nozzle 3, shown in Figure 6. Crack 4 in Nozzle 3 appears to have grown from the weld toward the ID of the nozzle; however, in this case, another crack appears to have initiated on the ID surface of the nozzle and grown outward toward the larger crack. Two more similar examples of OD and ID initiated cracks growing toward one another can be seen in the UT profiles of Cracks 4 and 10 of Nozzle 2 (see Reference 4) The presence of the larger cracks likely raised the stress at the ID of the nozzle wall above the weld sufficiently to initiate ID cracks. Based on the crack driving force and growth rate calculated for the postulated crack in Figure 4, the two cracks shown in Figure 6 would likely have grown together (i.e., linked up) in a matter of months, had they not been removed from service in February 2002. The UT examinations could not reliably detect, or see, cracking in the J-groove welds beyond the OD of the nozzle walls; yet, cracking profiles like those shown in Figure 5 and Figure 6 strongly suggest that the J-groove welds were also cracked, especially in light of the fact that much of the industry data for PWSCC growth in Alloy 182 shows higher CGRs, on average, than in Alloy 600.
Figure 7 shows results from a simulation that postulated a long, shallow, axial crack at the highest stress location on the ID surface of the nozzle, which is slightly above the top of the weld. The ID hoop stress in that region from the finite element analysis is 36 ksi under operating conditions. This type of long, shallow crack can develop as a result of link-up of a number of smaller, collinear, ID PWSCC crack initiations. Growth from the initial 0.03-inch depth to break-through at the top of the weld is predicted to take just over three years, ignoring any link-up with other cracks. However, the profile of Nozzle-3 Crack 4, shown in Figure 6, clearly indicates how multiple cracks could link up and increase overall crack size in a short period of time, much less than predicted by assuming growth of only a single crack. This is further supported by the analysis results. The ID-crack growth schematic in Figure 7 includes NASCRAC is a trademark of Exponent, Inc. B-3 BN63097.001 B0T0 1106 DB05
an overlaid outline of the weld-bottom crack from Figure 4. This comparison indicates that two such cracks, one growing from the highest stress location on the OD and one growing from the highest stress location on the ID, could readily link up to form a single, much larger crack in roughly three years time. The magnitude of K at the upper and lower crack tips of the combined crack would be greater than that of the two individual cracks prior to link up, and thus, the crack growth rates would increase after link up.
As mentioned previously, the final observed profile of Crack 1 in Nozzle 3 does not lend itself well to idealization with either a buried elliptical crack model or a surface semi-elliptical crack model. However, these models can be used to conservatively estimate the crack driving force, and thus the CGR, at the upper tip of Crack 1 in Nozzle 3 as it grew above the top of the J-groove weld. Figure 8 shows calculated K-values for a series of semi-elliptical cracks of increasing length above the top of the weld. The lower crack tip of each crack was held fixed at 1.2 inches below the bottom of the weld and the crack depth measured from the nozzle ID was held constant at one inch, well into the weld. As was done with the buried elliptical crack simulation of weld-bottom crack growth, the regions of this large crack that extend outside the nozzle wall and weld were assigned zero values of stress for the weight-function integration of K. For comparison, the actual final size of Crack 1 in Nozzle 3 was larger than the largest of these postulated cracks. It extended 1.2 inches above the weld and 1.6 inches below the weld, almost to the end of the nozzle, and deeper into the weld. Several different crack lengths were chosen for analysis to examine the variation in crack driving force with crack length above the top of the weld. The predicted crack driving force, K, at the upper crack tip under operating conditions ranged from 53 ksi in1/2 when the upper tip was even with the top of the weld down to 24 ksi in1/2 for a crack extending to 1.2 inches above the top of the weld. These K values were used to interpolate corresponding crack growth rates for the Davis-Besse Nozzle-3 Alloy 600 using the curve shown in Figure 3.
Figure 9 shows PWSCC growth rates for the upper tip of a long axial crack in the nozzle wall based on interpolation in Figure 3 using the calculated crack driving force values shown in Figure 8. Also plotted are the K-values themselves as a function of crack length above the weld.
We expect the actual K-values and corresponding CGR at the upper tip were greater than NASCRAC is a trademark of Exponent, Inc. B-4 BN63097.001 B0T0 1106 DB05
predicted for the latter stages of growth, due to the larger size of Nozzle-3 Crack 1 compared to this approximation. This would be the case until late in the development of the head wastage cavity when loss of head material behind the weld likely reduced the residual stress level in the J-groove weld, as was predicted by a DEI simulation5. These estimates of growth rate for the upper end of the long axial crack in Nozzle 3 are substantially greater than any prior estimates by others, yet they are consistent with the measured growth rates for Nozzle-3 material, the large size of the observed crack, and the high weld and nozzle stresses predicted by our analysis, as well as similar analyses by others6,7,8.
The interpolated crack growth rates shown in Figure 9 were integrated to obtain estimates of the time to grow the upper crack tip in Nozzle 3 to various heights above the top of the weld, thus creating a leakage path. Figure 10 plots growth time in effective full-power years (EFPY) as a function of crack length above the top of the weld. These results indicate that all of the growth above the top of the weld of Crack 1 in Nozzle 3 at Davis-Besse likely occurred in less than three EFPY.
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Figure 1. Schematic of four-degree-of-freedom model for a buried elliptical crack from the NASCRAC Software.
Figure 2. Schematic of three-degree-of-freedom model of a semi-elliptical surface crack in a cylinder from the NASCRAC Software.
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Figure 3. Comparison of PWSCC crack growth rate curve fit for Alloy 600 from Davis-Besse Nozzle 3 to EPRI/MRP Alloy-182 disposition curve.
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Figure 4. Simulation of PWSCC growth from a postulated 0.010-inch initial crack at the bottom of the weld on the nozzle OD. Break-through to nozzle ID predicted in 3.2 years.
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Figure 5. Proportionally scaled UT profile of Crack 1 in Nozzle 2 based on Framatome UT examination results. [Adapted from Reference 4.]
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Figure 6. Proportionally scaled UT profile of Crack 4 in Nozzle 3 based on Framatome UT examination results. [Adapted from Reference 4.]
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Figure 7. Simulation of growth from a postulated shallow (0.03-inch deep), 0.6-inch long crack at the peak stress location on the nozzle ID to break-through above the top of the weld in 3.2 years. Outline of weld-bottom crack shown in Figure 4 indicates link-up of two such cracks could occur to form a single larger crack.
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Figure 8. Calculated K-values for a series of deep, semicircular ID cracks in the nozzle, extending into the weld for estimation of crack growth rates and growth time above the top of the weld.
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Figure 9. Approximate K-values and corresponding PWSCC growth rates for postulated long ID cracks in the nozzle, extending from 1.2 inches below the weld to the indicated length above the weld, as shown in Figure 8.
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Figure 10. Approximate time in effective full-power years to grow the upper tip of the long axial crack in Nozzle 3 to various lengths above the top of the weld.
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References
- 1. NASCRAC, NASA Crack Analysis Code, Version 3.2, Exponent, Inc., 1999.
- 2. B. Alexandreanu et al., Crack Growth Rates in a PWR Environment of Nickel Alloys from the Davis-Besse and V.C. Summer Power Plants, NUREG/CR-6921, U.S. Nuclear Regulatory Commission, November 2006, at Page 68.
3 Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82, 182, and 132 Welds (MRP-115), EPRI TR-1006696, Electric Power Research Institute, Palo Alto, CA, November 2004, at Page 4-4.
- 4. M. Hacker, Davis-Besse CRDM Crack Profiles, Framatome ANP Engineering Information Record No. 51-5018376-00, May 13, 2002.
5 J. Broussard, Davis Besse CRDM Nozzle Crack Opening Displacement Analysis, Calculation C-5509-00-7, Revision 0, Dominion Engineering, Inc., March 19, 2002, at Page 3 of 7.
6 Safety Evaluation for B&W-Design Reactor Vessel Head Control Rod Drive Mechanism Nozzle Cracking, BAW-10190P, B&W Nuclear Technologies, May 1993.
7 J. Broussard and D. Gross, Welding Residual and Operating Stress Analysis of RPV Top and Bottom Head Nozzles, Proceedings of the Conference on Vessel Penetration Inspection, Crack Growth and Repair, NUREG/CP-0191, U.S. Nuclear Regulatory Commission, September 2005.
8 D. Rudland et al., Analysis of Weld Residual Stresses and Circumferential Through-Wall Crack K-solutions for CRDM Nozzles, Proceedings of the Conference on Vessel Penetration Inspection, Crack Growth and Repair, NUREG/CP-0191, U.S. Nuclear Regulatory Commission, September 2005.
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