RELIABILITY AND RISK ASSESSMENT GROUP
WESTINGHOUSE ELECTRIC COMPANY’S NUCLEAR SERVICE DIVISION

PITTSBURGH, PENNSYLVANIA

Mr. Bishop has been at Westinghouse for almost 35 years, working primarily in the area of structural reliability analysis, initially on breeder reactor core components and then on light water RPVs, piping and other primary loop components. During this time, Mr. Bishop developed and applied the structural reliability and risk assessment (SRRA) models, methods and software PFM analyses supporting a number of risk informed inspection initiatives. Included are the SRRA applications for most plant piping, reactor internals and reactor coolant pump components, and the irradiated belt line region, head penetration nozzles and nozzle inner radius region of the RPV. Mr. Bishop has been the recipient of six George Westinghouse Signature Awards for Engineering Excellence and two Special Recognition Awards from the ASME Pressure Vessel and Piping Division for conference tutorials on Application of Probabilistic Structural Mechanics. He has participated in the development and presentation of numerous Westinghouse technical reports and more than 35 publications on application of structural reliability to risk informed decisions, including a chapter on pressure vessel and piping applications in the Probabilistic Structural Mechanics Handbook. Mr. Bishop, a member of the editorial boards for Reliability Engineering and System Safety and Nuclear Engineering and Design, is currently a member of the ASME Safety Engineering and Risk Analysis Division and the ASME Codes and Standards Working Groups on Implementation of Risk-Based Inspection and Operating Plant Criteria (for RPV integrity issues). He also actively participates in the PWR Materials Reliability Program (MRP) Issue Task Groups on Reactor Vessel Integrity and Alloy-600 Issues, including the PFM analyses of the RPV during postulated PTS events and the Alloy 82/182 butt welds that are subject to PWSCC.

The first part of the presentation was presented by Chris Bell (Rolls Royce) with the final few slides presented by Vic Chapman. Chris presented the general assumptions and methodology of the PRODIGAL code. Note that PRODIGAL actually has several modules. One of them is to determine weld defect size from welding information. Another is to determine failure probabilities for navy nuclear power plants. All results presented are for a per weld basis.

In PRODIGAL, surface imperfections with a depth of 0.004 inch (0.1 mm) are assumed, but there are no SCC initiation/growth models in PRODIGAL. Past study has shown that there is little sensitivity to the assumed depth and sizes much less than 0.004 inch (0.1 mm) have little effect. For surge line case, there is sensitivity to the existence of 0.04 inch (1 mm) defects, see slide 19.

Based on some work of Ritchie, Pete Riccardella felt that the 0.004 inch (0.1 mm) initial defect size was near the LB of the region where fatigue crack growth (da/dN) models were valid. It was noted that Omesh Chopra from Argonne thinks that this lower limit is closer to 0.02 inch (0.5 mm). It was suggested that this limit is dependent on the grain size of the material. Note, cast stainless steels can have very large grain sizes.

Vic and Chris felt that they could not do a generic analysis for seismic considerations since the effect of seismic has been found to be highly dependent on plant layout. Therefore they didn’t consider seismic stresses in their analysis. In addition, they only considered the three PWR base cases since they had little experience with BWRs.

They used the same stress data as Dave Harris did for consistency purposes. As Dave did, they used a second order distribution of stresses thru the thickness per NUREG/CR-5505 criteria that was done by PNNL in 1998.

The failure criterion for their instability analysis is based on the FAD approach in R6 using KIC, i. e., crack initiation would equal failure. The crack initiation used for stainless steel was closer to wrought base metal rather than weld metal which would be an order of magnitude lower, or aged cast stainless steel which could be another factor of 3 lower than the weld metal toughness.

Bruce Bishop asked what the mean temperature in the analysis is used for. It is used for material property considerations, such as flow stress, but not for subcritical crack growth. Slide 16 from Vic and Chris’ presentation shows the cumulative probability of a TWC (probability of a leak occurring). The implication from this slide is that if you are going to have a leak, it will occur in the first 25 years of operations. It was noted that slide 16 is conditional on having a crack (probability of having a crack is 1).

Rob Tregoning indicated that he wants each of the panel members in the next week to make list of what they want to see (e. g. data they used in doing their analysis) from either individual participants or from the group as a whole.

It was noted that the dominant hot leg cycles are those due to heat up and cool down. There are only on the order of 5 of these cycles per year.

Pete Riccardella thought that there were a lot of cycles on the PWR HPI/Make up nozzle each year. Dave Harris countered that he thought that there were only about 40 of these cycles in 40 years of operations. Bengt Lydell agreed with Pete and thought there were a lot of thermal cycles. Pete thought that something was missing here. Bengt said there was a nice ASME paper on the cyclic stress history of these nozzles that we could use in the analysis.

Chris indicated that although they typically keep the aspect ratio constant in their PRODIGAL runs, they have the ability to grow cracks in length, and often get very irregular crack shapes.

In slide 24, the “separation” referred to is the crack-opening displacement. In this slide, at the surge line elbow, Vic speculates that the crack starts to act as a hinge so that crack opening becomes very large for the longer crack lengths. This assertion is the basis for slide 25 illustration of the crack frequency versus

angle distribution that was assumed in the analysis. This relationship was created by Vic with guidance from metallurgist to rectify predicted and experimental crack lengths.

It was commented that for the same input, we are seeing similar results from PRAISE (Dave Harris’ results) and PRODIGAL (Vic Chapman and Chris Bell’s results). It was noted that as far as this exercise is concerned, PRODIGAL’s strength is the defect distribution analysis. PRODIGAL only looks at thermal fatigue while PRAISE can look at other failure mechanisms. PRAISE can also look at crack initiation while PRODIGAL cannot. However, neither accounts for FAC or PWSCC at this time.

PRAISE can also look at crack initiation whereas PRODIGAL assumes crack growth from weld defects or surface imperfections.

Vic pointed out that embedded cracks can straddle the compressive zone of the residual stress field through the thickness so that once they break thru to inside surface they are already through the compressive zone. This is in contrast to case where a crack is growing through the wall thickness from the inside pipe surface and the crack gets trapped in the compressive zone near mid thickness. There was also the question of whether embedded cracks are affected by the environment.

The next topic for discussion was to plan the next step for the base case calculations.

Bruce Bishop would like to bench mark the PFM results against the 25 operating-experience estimates developed by Bill Galyean and Bengt Lydell, and then use the PFM models (PRAISE and PRODIGAL) to predict the 40 and 60 year results. Rob Tregoning thought that this was an excellent idea. Rob also indicated that we could do this for some cases, but not all cases, e. g., FAC in the feedwater system or PWSCC.

Sam Ranganath would like to know when we compare results where do we get good agreement and where not. Rob indicated that we haven’t made comparisons on a consistent basis as of this date but that this would be rectified.

The next issue focused on additional stresses to consider in the PFM results. The surge line and HPI/MU cases were mentioned. Dave Harris has already done some additional analysis for the surge line, based on refined stresses developed by Art Deardorff. Gery Wilkowski noted that he had surge line stresses from a Westinghouse Owner’s Group report used for LBB analyses. Pete agreed to verify that the previous stresses provided by Art are appropriate. Pete also agreed to provide more accurate HPI/MU stresses.

Sam Ranganath would like to lower the stresses to 10 ksi (70 MPa) for the recirculation line (BWR-1) and to lower the feedwater line stresses (BWR-2) by 20 percent.

The next area where the panel thought we may want to focus is some sensitivity analysis using different material properties. Gery Wilkowski volunteered to supply some distributions of material properties (mainly toughness values for welds and aged cast stainless steels) developed as part of NUREG/CR-6004.

Gery Wilkowski also wanted to see the ratio of surface crack to through-wall cracks removed from service, and the distribution of the lengths and depths of those service removed surface cracks. He then wanted to see a comparison of the PFM probability of leaks for IGSCCs from PRAISE and the distribution of surface cracks that might exist up to the time that piping might have been replaced/repaired (15 service years?). Karen suggested looking at the more recent results on a yearly basis because ISI wasn’t sensitive enough to find surface defects in early years. Cracks were only discovered once they became a leaking crack. Also, in Sweden, even if whole pipe sections were removed, all the welds were inspected, whereas in the US if the pipe system was replaced they did not spend the effort to inspect welds that were being removed from service. Hence, the database of cracks removed from service should separate Swedish and US plants. The important aspect of this comparison is to see the population of the ISI remove surface crack lengths compared to the surface flaw sizes calculated by PFM. If the service removed crack lengths from ISI are much longer than calculated by the PFM analyses, then the PFM analysis should underestimate the future failure probabilities. Gery noted several times that failure probabilities should be controlled by development of long surface cracks, not the growth of leaking through-wall cracks. Bengt Lydell has some papers relating ISI-detected surface-crack geometries to through-wall crack leaks that he can provide on the ftp site and can provide to Rob Tregoning.

It was suggested to include PWSCC in the hot leg base case analysis. Dave Harris has initially done this using IGSCC relationships for preexisting flaws. Initiation is not accounted for. Gery Wilkowski noted that the crack growth rate through the weld metal (along the dendritic grains) is much faster than IGSCC. Gery will work with Karen Gott and Bill Cullen to see how Dave can adjust the PRAISE model to get initiation and growth for PWSCC. Gery will provide the IGSCC initiation and growth equations that PRAISE uses to Bill Cullen so that appropriate constants can be provided for PWSCC in PRAISE for base case calculations. Gery and Karen will provide information to Dave Harris on PWSCC crack initiation and growth models that he can use to evaluate the impact of PWSCC on the appropriate base case calculations.

The panel thought it was important to address Dave Harris’ strange results for weld overlay repairs. What is leading to high growth rates after the overlay is applied. Can a comparison be shown with what would happen if no weld overlay had been applied? Dave Harris is to address this concern of the unexpectedly high growth rates after the weld overlay repair is applied.

When the summary comparison tables are completed, the PFM subgroup needs to clearly identify where the PFM conditions do not agree with operating experience. Rob Tregoning indicated that the base case subgroup needs to finish up the base case calculations by the end of the month. We cannot delay individual elicitations any longer.

Existing service experience with piping systems shows a strong correlation between failures and presence of an active degradation mechanism in combination with service conditions and transient loading conditions. It is therefore possible to estimate piping reliability parameters through statistical analysis of service experience data. Such analysis includes data processing whereby the appropriate reliability attributes are correlated with influence factors as described in SKI Report 97:26 [D.11].

In this Base Case Report the technical approach to LOCA frequency estimation builds on statistical analysis of service data associated with ASME XI Class 1 piping in the BWR and PWR operating environments. The study accounts for two kinds of uncertainties in piping reliability analysis, namely data uncertainty and state — of-knowledge uncertainty. The pipe failure database on which this study is based is called PIPExp [D.12], which is the extended version of the OPDE pipe failure database [D.13]. A description of PIPExp is included in Appendix A. The uncertainty analysis is performed by using a Monte Carlo merge technique to develop the LOCA frequency distributions. A commercial software package called Crystal Ball (Version 2000.2.2), which is an add-on for Microsoft Excel, is used to perform this Monte Carlo merge operation. Time- dependent LOCA frequencies are developed using a Markov modeling approach [D.14].

The BWR Base Case analysis is based on the degradation mechanism analysis as documented in Reference [D.5], and it builds on insights from an earlier BWR LOCA frequency pilot study [D.15-D.16]. The PWR Base Case analysis is based on the degradation mechanism analysis as documented in References [D.6, D.8], and builds on insights and results from an earlier sensitivity analysis performed in support of a risk informed

inservice inspection (RI-ISI) evaluation [D.12]. That sensitivity analysis addressed the impact of using a different pipe failure database on the RI-ISI weld selection.

MEETING MINUTES FROM GROUP PANEL MEETINGS

In this appendix the meeting minutes from the three group meetings of the expert panel are presented. First the meeting minutes from the kick-off meeting are presented, followed by the meeting minutes from the base case review meeting. Lastly, the meeting minutes from the wrap — up meeting of the elicitation panel are presented.

There was quite a bit of disagreement on first bullet on with regards to the perceived disadvantages of the various approaches.

Bruce argued that PFM approaches have been benchmarked against operating experience and shown to agree well.

Helmut and Bruce stressed that we are not in a position to review various approaches and we should not provide such a review in the NUREG report.

Need to stress in NUREG that general comments are not a group consensus, but individual responses.

Using the information in Section D.4, this section documents the input data to the LOCA frequency model. A Bayesian update is performed to develop posterior weld failure rates. The frequency of leaks exceeding Technical Specification limits are developed through estimates of the conditional probability of a large leak given a small through-wall flaw.

D.5.1 Posterior Weld Failure Rates

The failure rate calculation involves two factors, the number of applicable failures and the exposure data. To account for uncertainty in the exposure data, which could influence the failure rate calculation the following process is used. First, a best estimate update is performed using the appropriate number of failure events and the number of welds of exposure. To account for plant-to-plant variability in the weld exposure term, a second update is performed using the same failure data but an exposure estimate that is 50% higher, and a third update using an exposure estimate that is 50% lower. Each of the three updates is combined in a posterior weighting process using the following weights: 50% for the best estimate, 25% for the high exposure case and 25% for the low exposure case. The result is an uncertainty distribution for each failure rate, which reflects greater uncertainty than the best estimate data would imply alone. The results are given in Tables D.12 and D.13; Attachment B includes the input to the failure rate calculation. Figure D.19 displays posterior IGSCC flaw frequencies. Figures D.20-D.23 compare the prior and posterior non-through wall crack frequencies.

Table D.13 Posterior RC and HPI/NMU Weld Failure Rate Distributions — PWR Base Cases

□ NPS1 2

□ NPS22

1.00E-03

1.00E-06

> 10% > 20% > 30% > 40% > 50% > 60% > 70% > 80% > 90%

a/t-Ratio

Figure D.19 Posterior IGSCC Frequency (Non-Through Wall)

1.00E-02

1.00E-06

> 10% > 20% > 30% > 40% > 50% > 60% > 70% > 80% > 90%
a/t-Ratio

Figure D.20 Prior and Posterior IGSCC Frequency (Non-Through Wall) for NPS12 Welds

> 10% > 20% > 30% > 40% > 50% > 60% > 70% > 80% > 90%
a/t-ratio

Figure D.21 Prior and Posterior IGSCC Frequency (Non-Through Wall) for NPS22 Welds

1.00E-02

1.00E-03

1.00E-04 1.00E-05 1.00E-06

> 10% > 20% > 30% > 40% > 50% > 60% > 70% > 80% > 90%
a/t-Ratio

Figure D.22 Prior and Posterior IGSCC Frequency (Non-Through Wall) for NPS28 Welds

During the elicitation, each panelist will determine the biggest contributors for each LOCA frequency threshold category (Table B.1.1) separately for BWR and PWR plants. The information summarized in Tables B.1.2 — B.1.8, and discussed in the previous sections, is simply intended to identify those issues and variables which contribute to the LOCA frequency distributions. Each panelist will determine the magnitude and likelihood of each variable separately, but more importantly will determine the importance of the interrelationships among the variables.

Each panel member will not be asked to provide absolute LOCA frequencies. All questions will be structured so that relative differences with a specific base case will be queried. The base cases will be associated with absolute frequencies and quantitative LOCA estimates will be derived from these values and the relative relationships provided during the elicitation. The group spent quite a bit of time and effort both understanding the role of the base cases in the elicitation and assessing their importance. Ideally the base cases are chosen to represent significant contributing conditions to the total LOCA frequency estimates in order to minimize the extrapolation required during questioning. Representative, significant base cases should therefore theoretically improve the elicitation accuracy. Once this concept was understood, the group settled on several base case conditions for PWR and BWR systems. Pete Riccardella provided the original suggestions which were largely adopted by the panel after the analysis framework was clarified. The base case discussion evolved over the Wednesday and Thursday meeting days. All of the discussion will be summarized in this section for consistency.

Two base cases were developed for BWR piping systems (Table B.1.9). The first case will examine the recirculation system piping. All the various piping sizes will be considered, and original 304 stainless steel material will be assumed that has not been replaced during plant operation. The safe end is non­creviced Alloy 600 which is connected to the piping and vessel by Alloy 82/182 weld material. Only the IGSCC (subcategory of SCC, Table B.1.2) will be considered as the degradation mechanism. The loading will consist of pressure, residual stress, and dead weight nominal components. Transients to be considered include SRV loads and seismic. The base case will assume that NWC is used in the system.

The next BWR base case will examine the feed water system. A 12 inch diameter carbon steel pipe will be analyzed. The safe end and weld materials were not specified and will need to be defined by the base case analysis team (to be discussed subsequently). The degradation mechanisms for this base are FAC and TF. Loading sources include pressure, thermal, residual stresses, and dead weight nominal components. Thermal fatigue loading from stratification and possibly striping will provide alternating loads, and water flow velocities will also be included to assess fluid loading. Transients for this base case will include water hammer and seismic. Once again NWC will be assumed.

Three base cases were constructed for PWR systems (Table B.1.9). The first will examine the hot leg in the reactor coolant piping system. A 30 inch diameter Type 304 stainless steel pipe will be considered with Alloy 600 safe ends and Alloy 82/182 bimetallic welds. This base case will examine thermal fatigue and PWSCC. Loading will again include pressure, thermal, residual stress, and dead weight nominal loads and thermal fatigue alternating loads. Transients will include seismic loading and a pressure pulse transient, the magnitude and duration of which is still to be determined.

The next PWR base case is a 10 inch diameter surge line. The surge line material is Type 304 SS and an Alloy 82/182 bimetallic weld will be included at the pressurizer. No safe end materials will exist. Once again, thermal fatigue and PWSCC will be considered. Loading will include pressure, thermal, residual stress, and dead weight nominal loads and thermal fatigue alternating loads. Transients will include seismic loading and a pressure pulse transient, the magnitude and duration of which is still to be determined.

The final PWR base case was the most ill-defined case because it was added after initial group discussions. It was added to provide a base case for a smaller diameter piping system. This base case will need to be defined more completely prior to analysis. A 4 inch diameter high pressure injection/makeup (HPI/MU) line will be examined for thermal fatigue degradation. The piping material, welding, and safe end materials still need to be specified. Nominal loading is once again provided by pressure, thermal, residual stress, and dead weight loads. Thermal alternating loads will be defined and seismic and pressure pulse transients will be considered.

Absolute LOCA frequencies will be developed for each base case and for each threshold leak rate category defined in Table B.1.1. There are six leak rate categories and five base cases; therefore at least thirty separate calculations will be required to fully define the base case frequencies. The base cases will include analysis of many welds and other piping components. The LOCA frequencies for the system will obviously be the summation of the contributions from all system components. The frequencies will also be determined as a function of time. Three time periods will be evaluated: 25 years after plant startup (current-day), 40 years after start-up (end-of-plant-license), and 60 years after start-up (end-of-plant- license-renewal).

The panel decided that seismic transients would be handled as part of a sensitivity study. As mentioned previously, seismic-induced LOCAs will not be determined as part of this elicitation for several reasons: the PRA models that these estimates will be used for do not consider seismic loading; there has been significant work in developing seismic LOCA estimates; and the group has no specific expertise in seismic analysis. However, many panel members are experienced in conducting analysis when the seismic loading history is provided. Many panel members also seem comfortable with comparing other loading histories to seismic events. Therefore, it was decided that the elicitation would ask for

comparisons with conditional seismic loading (probability of occurrence of 1) separately in order to conduct a sensitivity analysis of the effect of seismic loading.

Originally, the group determined that the seismic loading magnitude will be 0.3 g for the sensitivity study. Pete Riccardella suggested changing the 0.3 g criteria for the seismic condition to an ASME Code faulted-stress condition. By doing this soil conditions, damping characteristics, etc. do not have to be considered. While there was some discussion on the merits of this suggestion, the issue was not finalized.

The base cases will also perform a sensitivity analysis to determine the effect of the frequencies both with and without ISI. Standard ISI techniques will be considered in the analysis. Credit will also be given in this analysis for leak detection. The leak detection threshold for the base case analysis will be leak rates which are commensurate with the data defined in the SKI-pipe database. The specific leak rate threshold associated with the database must be defined.

A base case team was established to develop four separate LOCA frequency estimates for each of the five base cases. The base case team will consist of Vic Chapman, Bengt Lydell, David Harris, and Bill Galyean. The team will model a specific piping system and define plant operating characteristics for each base case. Then, the team will develop input for each of the five LOCA variables (material, geometry, loading, degradation mechanism, and mitigation/maintenance) within the parameter constraints identified in Table B.1.9. The team will share information to ensure that each analysis is considering the same nominal conditions for each base case.

Each base case team member will develop their own LOCA estimates for each system using whatever methodology they choose. The likely general approaches for each team member are summarized in Table B.1.10. Each specific methodology will require additional assumptions. It is incumbent that each team member catalog required assumptions and document the methodology used to arrive at their base case LOCA estimates. This information will then be rigorously, yet concisely, presented to the remaining panel members. This should allow each panel member to completely understand the assumptions, methodology, and results generated by each base case team member. It needs to be stressed that once the general conditions are developed, the base case members should independently develop their estimates without further consultation. This step is necessary to retain realistic sample uncertainty in the calculated results.

The base case team would collaborate to ensure that the PFM analyses accurately capture that leaking pipe operating experience. This is the one aspect of the exercise that contains plant operating experience data. Initial PFM calculations will be conducted based on best-estimate assumptions and the current leak rate frequency predictions will be compared with the operating experience. At this point, PFM input assumptions may be changed in order to match the operating history. Each PFM model should accurately document the input variables, any model changes, and results both before and after benchmarking. This benchmarking exercise will help the remaining panel members gauge uncertainty in the calculations.

The panel will supply background information to the base case calculation team as required. All requests for background information will be coordinated by Rob Tregoning to ensure proper cataloging and dissemination to the group. Some volunteers already offered certain background information. Bruce Bishop has run his own PFM models for seven Westinghouse plants that could ultimately be used to help verify the base case calculations.

It was also stressed by the panel that it is important to make the PFM modeling conditions as close as possible to the postulated service conditions so that the various base case approaches can be directly compared to assess uncertainty and possible inaccuracies. For instance, many existing PFM models assume that all repairs are perfect (no defects). However, many repairs introduce new defects and most large flaws are associated with repairs. This fact (and other similar issues) is naturally captured within the operating-experience database, and needs to be considered within the PFM modeling if possible.

Rob discouraged panel to make changes to bring their results more in line with others, would encourage panel to make changes if they heard something technically that made them rethink their answers.

Everyone will be involved in reviewing and critiquing NUREG reports; everyone wanted to be involved with the process.

The question of how: possibly another meeting, VTC, circulate vugraphs for review and feedback (electronically); possibly couple with some other meeting (ASME, PVP, etc).

Karen and Dave would want to meet before the NUREG was finalized; others seemed to agree with this.

Ideally we would circulate draft, we would then get comments back, we would then synthesize comments and then feed them back to the group and then meet; all before finalizing NUREG.

Helmut and Bruce supported idea of VTC (maybe limit to a few sites).

Other option is provide slides; review slides on computer and then have a conference call to review; limit to a few hours at a time (bite off small chunks).

Mr. Chapman has a Diploma in Engineering and an Honors Degree in mathematics. He has worked in the pressure system design and maintenance field for over thirty years. Over this period he has gained experience in the design and fracture analysis of pressure vessels, the study of material properties and the statistical interpretation of data. Over the past twenty-five years he has concentrated on the area of PFM, risk based decision-making, risk based inspection and inspection qualification. He was responsible for the introduction of the Risk-Based ISI program into the Royal Naval Nuclear Fleet.

Mr Chapman retired from Rolls Royce (Naval Nuclear Division) four years ago and became an independent consultant, forming his own company, O J V Consultancy Ltd. In addition to his consultancy work, which is funded by many organizations and international bodies, he has played a leading role on several international committees:

He is currently Chairmen of ENIQ-TGR (European Network for Inspection & Qualification-Task Group on Risk).

A member of the European program NURBIM (Nuclear Risk-Based Inspection Methodology).

A member of the ASME Research Committee on Risk Technology.

He chaired the European program EURIS (European Network of RI-ISI).

Was a member of the ASME Research task force on Risk Based Inspection — Developed of Guidelines.

Was a member of the UK Technical Advisory Group on Structural Integrity (TAGSI) sub-committee on defects in welds.

Rob Tregoning started the morning by reviewing the agenda for the second day. There were six (6) basic items to cover. These were:

• Reviewing the elicitation questions

• Reviewing the leak rate versus pipe break size evaluation

• Addressing the non-piping LOCA evaluations

• Reviewing the conditional seismic evaluation

• Addressing the additional information required prior to the individual elicitations for piping and non-piping evaluations

• Elicitation scheduling

The specific objectives for the second day included:

• Finalize the elicitation question sets and to provide a consistent understanding of each question.

• Determine the methodology for evaluating non-piping LOCAs and the identification of non­piping base case data.

• Determine the methodology for evaluating conditional seismic loading including determination of the seismic loading magnitude.

• Determine what information the panelists will require prior to their elicitations and assign action items for providing information.

• Develop the final schedule and time-frame for the upcoming elicitations.