ML20307A524
| ML20307A524 | |
| Person / Time | |
|---|---|
| Issue date: | 09/22/2020 |
| From: | Advisory Committee on Reactor Safeguards |
| To: | |
| Widmayer, D, ACRS | |
| References | |
| NRC-1104 | |
| Download: ML20307A524 (117) | |
Text
Official Transcript of Proceedings NUCLEAR REGULATORY COMMISSION
Title:
Advisory Committee on Reactor Safeguards Future Plant Designs Subcommittee Docket Number:
(n/a)
Location:
teleconference Date:
Tuesday, September 22, 2020 Work Order No.:
NRC-1104 Pages 1-81 NEAL R. GROSS AND CO., INC.
Court Reporters and Transcribers 1323 Rhode Island Avenue, N.W.
Washington, D.C. 20005 (202) 234-4433
NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
(202) 234-4433 WASHINGTON, D.C. 20005-3701 www.nealrgross.com 1
1 2
3 DISCLAIMER 4
5 6
UNITED STATES NUCLEAR REGULATORY COMMISSIONS 7
ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 8
9 10 The contents of this transcript of the 11 proceeding of the United States Nuclear Regulatory 12 Commission Advisory Committee on Reactor Safeguards, 13 as reported herein, is a record of the discussions 14 recorded at the meeting.
15 16 This transcript has not been reviewed, 17 corrected, and edited, and it may contain 18 inaccuracies.
19 20 21 22 23
1 UNITED STATES OF AMERICA 1
NUCLEAR REGULATORY COMMISSION 2
+ + + + +
3 ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 4
(ACRS) 5
+ + + + +
6 FUTURE PLANT DESIGNS SUBCOMMITTEE 7
+ + + + +
8 TUESDAY 9
SEPTEMBER 22, 2020 10
+ + + + +
11 The Subcommittee met via Video-12 Teleconference, at 9:30 a.m. EDT, Joy Rempe, Chair, 13 presiding.
14 COMMITTEE MEMBERS:
15 JOY L. REMPE, Chairman 16 WALTER L. KIRCHNER, Member-at-large 17 RONALD G. BALLINGER, Member 18 CHARLES H. BROWN, JR. Member 19 VESNA B. DIMITRIJEVIC, Member 20 JOSE MARCH-LEUBA, Member 21 DAVID A. PETTI, Member 22 MATTHEW W. SUNSERI, Member 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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2 ACRS CONSULTANT:
DESIGNATED FEDERAL OFFICIAL:
3 DEREK A. WIDMAYER 4
ALSO PRESENT:
5 TAMARA BLOOMER, RES 6
JOHN TOMON, RES 7
KIM WEBBER, RES 8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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3 AGENDA 1
Opening Remarks.................
4 2
Staff Introduction and Overview 3
Radiation Protection Code Modernization..
7 4
Non-LWR Code Development, Volume 4, 5
"Licensing and Siting Dose Assessment Codes" 6
Discussion of Licensing and Siting Dose 7
Assessment Codes 8
Discussion of Volume 4 Tasks 9
Leveraging Other Non-LWR Code Readiness Work 10 Other non-NRC Dose Assessment Codes for 11 Non-LWR Readiness & Other Considerations. 20 12 Discussion................... 73 13 Adjourn
.................... 81 14 15 16 17 18 19 20 21 22 23 24 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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4 P R O C E E D I N G S 1
9:30 a.m.
2 MEMBER REMPE: Good morning. This meeting 3
will now come to order. This is the meeting of the 4
Advisory Committee on Reactor Safeguards, Subcommittee 5
on Future Plant Designs.
6 I'm Joy Rempe and I'm chairing the Future 7
Plant Designs Subcommittee today. ACRS members in 8
attendance include Charlie Brown, Walt Kirchner, David 9
- Petti, Jose March-Leuba, Ron Ballinger, Vesna 10 Dimitrijevic, Matt Sunseri, and we expect to be joined 11 by Pete Ricardella later in the meeting.
12 We also have our consultant, Mike 13 Corradini, in attendance. Derek Widmayer, of the ACRS 14 staff, is the designated federal official for this 15 meeting.
16 The purpose of today's meeting is to 17 review the draft report, NRC non-LWR Vision and 18 Strategy, Volume 4 -- help me out with -- the 19 Licensing and Siting Dose Assessment Codes.
20 The Subcommittee will gather information, 21 analyze relevant issues and facts, and formulate 22 proposed decisions and actions as appropriate.
23 This matter, along with a draft Volumes 1 24 through 3 in this report series, is scheduled to be 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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5 addressed at the October full Committee meeting.
1 The ACRS was established by statute and is 2
governed by the Federal Advisory Committee Act, FACA.
3 The NRC implements FACA in accordance with its 4
regulations, found in Title 10 of the Code of Federal 5
Regulations, Part 7.
6 The Committee can only speak through its 7
published reports. We hold meetings to gather 8
information and perform preparatory work that will 9
support our deliberations at a full Committee meeting.
10 The rules for participating in all ACRS 11 meetings, including today's, were announced in the 12 Federal Register.
13 The ACRS section of the U.S. NRC public 14 website provides our charter, bylaws, agenda, letter 15 reports, and full transcripts of all full and 16 subcommittee meetings, including slides presented 17 therein. The meeting notice and agenda for this 18 meeting were posted there.
19 As stated in the Federal Register, notice 20 and the public meeting notice is posted on this 21 website, members of the public who desire to provide 22 written or oral input to the Subcommittee may do so, 23 and should contact the designated federal official 24 five days prior to the meeting, as practicable.
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6 Today's meeting is open to public 1
attendance and we've received no written statements, 2
or requests to make an oral statement.
3 We've also set aside ten minutes in the 4
agenda for spontaneous comments from members of the 5
public attending or listening to our meetings.
6 Today's meeting is being held with a 7
telephone bridge line, allowing participation of the 8
public over the phone, and a transcript of today's 9
meeting is being kept. Therefore, we request that 10 meeting participants on the bridge line will identify 11 themselves when they speak, and to speak with 12 sufficient clarity and volume so they can be readily 13 heard.
14 Participants in the meeting room should 15 use the microphones -- excuse me. That's left over 16 from an old write-up and I forgot to cross that out.
17 But at this time, I do ask that all meeting 18 participants place themselves on mute, unless talking, 19 so that their cell phones or other devices that make 20 noise in the homes, such as clock bells, won't disrupt 21 this meeting.
22 And I will now proceed with the meeting 23 and call on Kim Webber, Deputy Director of the 24 Division of Systems Analysis, of the Office of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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7 Research, to make introductory remarks. Kim?
1 MS. WEBBER: Yes, thank you, Joy. And 2
good morning to you and the other members.
3 Thank you for taking the time to review 4
our latest volume of the Code Development Activities, 5
Volume 4, Licensing and Siting Dose Assessment Codes.
6 I'm going to skip to the next slide, since you 7
introduced me already.
8 By way of an agenda, I have with me today 9
John Tomon. He's the Chief of the Radiation 10 Protection Branch in my division. And he and his 11 staff have been working very hard with staff in NRR 12 and NMSS over the last several months to develop a 13 strategy that we believe is the most resource-14 effective approach for the codes covered by Volume 4, 15 and will ensure the safety as we conduct our licensing 16 review of non-light water reactors.
17 I'll provide high-level overview of the 18 status of the whole non-light water reactor code 19 development project, and a short introduction to 20 Volume 4. Then I'll turn the presentation over to 21 John, who's going to discuss the details of Volume 4, 22 including the topics shown on this slide and in the 23 agenda.
24 With non-light water advanced reactor 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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8 applications on our doorstep, including the March 1
submission of the Oklo application, our Office of 2
Research mission, now more than ever, is to enable the 3
regulatory offices to be ready to conduct their 4
licensing activities.
5 With our be-ready attitude, we are doing 6
research differently, by embarking on more be-ready 7
strategies, and transforming to become a more modern 8
risk-informed regulator.
9 To improve mission value, we are working 10 hard to deliver the tools, expertise, and information, 11 in a cost-effective and efficient manner, so that 12 licensing can be completed on time and within the 13 allotted resources.
14 A key element of this strategy is 15 developing the codes and analytical tools, like the 16 ones you see here, and having them ready to go for use 17 and safety analysis.
18 Through our code development activities 19 and collaborations with many organizations you see on 20 this slide, our staff has been acquiring a lot of new 21 knowledge about advanced reactor designs and phenomena 22 important to safety, thus growing staff expertise and 23 analytical capabilities, in addition to capturing 24 knowledge not only in the codes, but also in code 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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9 documentation.
1 To facilitate the agency's readiness, the 2
NRC's near-term implementation action plan was 3
developed in the summer of 2017. The IAP is the 4
vehicle to execute the NRC's vision to safely achieve 5
effective and efficient non-light water reactor 6
mission readiness.
7 As you know, the IAP includes six 8
strategies, which are shown here, and Strategy 2 9
focuses on computer codes and knowledge to perform 10 regulatory reviews. On the next slide I'll discuss 11 high-level progress made for Strategy 2.
12 As you know, earlier this year we 13 completed the Introduction, and Volumes 1 through 3.
14 We thank you for conducting an in-depth and thorough 15 review of our plans. Your views and perspectives 16 resulted in changes in those plans in support of the 17 realization of IAP Strategy 2.
18 Each report identifies the computer codes 19 that we may use for our independent safety analysis, 20 gaps in code development capabilities and data, 21 verification and validation needs, along with specific 22 code development tasks.
23 Volumes 1 through 3 focus on systems 24 analysis, fuel performance, neutronics, source term, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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10 severe accident progression, and accident consequence 1
codes.
2 If you'd like to follow the status of our 3
code development activities, you can go to the NRC's 4
advance reactor public webpage, which is shown on the 5
slide.
6 If you scroll down the page, and then 7
click on the summary of integrated schedule and 8
regulatory activities image, you'll see the status of 9
the near-term code development tasks for each volume.
10 Although not the subject for this meeting, 11 the status of code development activities for 12 Volumes 1 through 3 is provided for your reference in 13 the background slides, as Slide 34. At a later 14 meeting, we'll provide more information on these 15 activities.
16 As you
- know, we're developing two 17 additional volumes, Volume 4, which is the subject of 18 this meeting, and Volume 5, which focuses on code 19 development activities related to criticality and 20 shielding considerations for the front and back end of 21 the fuel cycle.
22 We had a meeting scheduled with the 23 Subcommittee on December 1st to talk with you about 24 Volume 5. We value your feedback and recommendations.
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11 As we requested a letter from you on Volumes 1 1
through 3, we are also requesting a letter from you on 2
Volumes 4 and 5. I believe a full Committee meeting 3
with a summary of Volumes 4 and 5 is being scheduled 4
for February.
5 Volume 4 provides an overview of the 6
radiation protection related to technical areas that 7
warrant code development modifications in our 8
literature reviews.
9 The codes that John will describe shortly 10 provide radiation dose assessment capabilities that 11 encompass nuclear power plant licensing, including 12 reactor siting, design basis accidents, and normal 13 effluent release analysis.
14 The codes also support dose assessment for 15 emergency response and severe accidents, and 16 atmosphere transport dispersion and site 17 decommissioning regulatory actions.
18 MEMBER REMPE: So --
19 MS. WEBBER: Depending on the --
20 MEMBER REMPE: Oh, I'm sorry. I thought 21 you were done. Go ahead, please finish your slide, 22 and then I have a question.
23 MS. WEBBER: Yes. Depending on the 24 analytical needs identified for these areas, the suite 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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12 of 10 codes, they needed to be modified for each 1
combination of fuel and advance reactor type, of which 2
there are many combinations.
3 To modify each of the codes for each fuel 4
reactor combination could be resource-intensive. And 5
that's a more resource-efficient approach is to 6
consolidate, while also modernizing, the codes. Going 7
forward, we would maintain the consolidated set of 8
codes.
9 As you know, code consolidation and 10 modernization also make sense since these codes have 11 been inconsistently maintained over the years based on 12 organizational needs, and there are overlaps in 13 models, dose coefficients, functionality, and use 14 cases.
15 Code consolidation and modernization are 16 natural progression steps in the lifecycle of computer 17 codes, and have been demonstrated successfully by the 18 NRC in the past.
19 For example, our trace thermal hydraulics 20 codes, MELCOR source term and severe accident code, 21 and our fast fuel performance code, have all undergone 22 consolidation and modernization efforts. And now, we 23 can go to your question, before I turn it over to 24 John.
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13 MEMBER REMPE: So, I have a couple of 1
questions. First off, with the earlier volumes, the 2
ongoing work with MELCOR and MACCS, because of later 3
questions I'm going to be bringing up, I know that 4
you're going to be giving us an update in a closed 5
session later on today, but can you say something 6
about the progress that's being made with applying 7
MELCOR in the open section?
8 Because I know there have been public 9
meetings about ongoing efforts with trying to apply 10 MELCOR for the various non-LWR technologies.
11 MS. WEBBER: Yeah. So, this is an image 12 from the public website. And what you can see is, in 13 the regulatory activity column, this is a list of all 14 of our code development activities for each of those 15 volumes.
16 So, here on this line you see Code 17 Assessment Report, Volume 1; Code Assessment Report, 18 Volume 2; Code Assessment Report, Volume 3. And you 19 see sub-level milestones under each of those.
20 And so, for Volume 3, which is focused on 21 MELCOR scale and MACCS, you can see a number of 22 different activities. And then over to the right, 23 whether those activities have been completed, or what 24 the target schedule is to complete those activities.
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14 And so what you'll see here is that for 1
Volumes 1 and 3, a lot of work has gone to develop 2
reference plant models for the different types of 3
reactors. And those reference plant models are 4
descriptions of different advanced reactor designs 5
based on publicly available information for the 6
different types of reactors.
7 And so you can see that for Volumes 1 8
and 2, many of those reference plant models have been 9
completed.
10 Additionally, for MELCOR and SCALE, 11 they're working on completing reference plant models 12 for several different advanced reactor designs. For 13 MACCS, there are plans to do some radium nuclide 14 screening
- analysis, and then the near field 15 atmospheric transport and dispersion model assessment 16 has been done.
17 So, I hope that this answers the question.
18 And we'll talk a little bit more about that in the 19 later session.
20 MEMBER REMPE: So, I appreciate this.
21 Again, because of upcoming letters or discussions, I 22 want to make sure what is it Camby said in the open 23 session. So, that's why I'm asking these questions 24 for you now.
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15 MS. WEBBER: Sure.
1 MEMBER REMPE: Now, the source term for 2
each technology -- although there may be gaps, which 3
I assume are identified in these ongoing efforts with 4
MELCOR -- but there is a base source term that could 5
be used as input for all these other Volume 4 codes.
6 MS. WEBBER: Yes.
7 MEMBER REMPE: Because you do depend on 8
MELCOR and MACCS to do the Volume 4 work.
9 MS. WEBBER: That's right.
10 (Simultaneous speaking.)
11 MEMBER REMPE: Right?
12 MS. WEBBER: Yes.
13 MEMBER REMPE: Okay. So, that helps a 14 lot. And then I draw your attention -- but you can 15 bounce this question to John Tomon -- but I guess I'm 16 one of the ACRS members that has the common 17 misconception mentioned in Volume 4, because actually, 18 we even discussed this at our prior meetings, about 19 why not have a simpler version of MACCS that can read 20 in those source terms from MELCOR, although other work 21 you're doing with Volume 3 codes, and really 22 consolidate things.
23 I mean, read in the local weather and have 24 something that is fast running with MACCS, instead of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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16 trying to consolidate the numerous codes we're going 1
to be hearing about with Volume 4.
2 To me -- and we discussed this before --
3 and I thought the prior transcript from the prior 4
meeting when I reviewed it, the staff said yeah, 5
that's a long-term goal, but we kind of wanted to do 6
this earlier mid-term consolidation.
7 And knowing -- I think even Volume 4 said 8
we're not going to plan up and running for five years, 9
where you have to worry about an emergency. It sounds 10 like you have a bit of time.
11 So, when I reviewed Volume 4, I really had 12 that question in my mind, and I wasn't convinced by 13 what I read that it was really necessary to go through 14 this intermediate step.
15 MS. WEBBER: So, because we recall that 16 that was a question you had raised, I think John 17 specifically is going to address that in his 18 presentation.
19 MEMBER REMPE: Good. Thank you.
20 MS. WEBBER: You're welcome. Any more 21 questions from the Committee?
22 MEMBER BROWN: Yeah, Charlie Brown.
23 MS. WEBBER: Hi, Charlie.
24 MEMBER BROWN: I'm not an expert in this 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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17 stuff, I'm the I&C guy. But I'm reading your approach 1
part and you talked about modernized dose assessment.
2 Now, we've been doing dose assessments and 3
stuff for over 60 years now for plants. And so I'm 4
just kind of curious what modernize means.
5 MS. WEBBER: I think in this context --
6 and John can correct me if I'm wrong -- modernization 7
means to go towards a code language that results in 8
faster speeds of codes and is able to be more 9
interoperable with multiple codes. I don't know, 10 John, if you want to nuance that answer.
11 MR. TOMON: Yes. Exactly what Kim was 12 saying is that many of the codes right now were built 13 kind of in silos and by themselves. And so 14 transferring input and output from one code to another 15 code usually involves many intermediate steps.
16 So, we kind of viewed this as modernizing 17 the codes so that they all work together. They use a 18 common language both in the inputs and the outputs, so 19 that the information can be transferred back and forth 20 fluidly between what we're calling -- and I'm going to 21 get to in a little bit -- the calculational engines 22 that actually do the actual calculations for the code.
23 MEMBER BROWN: Are the codes that NRC 24 uses? Or are you talking about the industry codes 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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18 that are developed by various, I guess, other bodies?
1 MR. TOMON: These are NRC codes. These 2
are our NRC codes that we've developed.
3 MEMBER BROWN: Okay, I understand that 4
then. Thank you.
5 MR. TOMON: Yes.
6 MEMBER REMPE: Out of curiosity, are the 7
codes in FORTRAN? And are you using just a new 8
version of FORTRAN, or are you going to a different 9
language?
10 MR. TOMON: Well, some of the codes are in 11 an older version of FORTRAN, some are in the newer 12 version, some are in Java. But it's really the output 13 files themselves in the data. They're not in a common 14 language, so usually you have to do some manipulation 15 by the operator and the user, and intermediate steps, 16 to either take a source term, or take an atmospheric 17 transport values, and then put them into the dose 18 assessment codes.
19 So, what we wanted to do was build a 20 construct -- as I'll get to -- that does this all, and 21 then it's one code that the user operates, and then 22 the information is passed fluidly from the input to 23 the output, and also guide the user, to ask the user, 24 what kind of outputs are you looking for, so that the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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19 user can really drive what he wants to see in the 1
output files.
2 MEMBER BALLINGER: This is Ron Ballinger.
3 Can't you just do this with scripts?
4 MR. TOMON: Well, for some of the codes we 5
could, but for most of the users it would be more, I 6
don't know, user-friendly just to have it all in one 7
area in the codes.
8 And there are some issues with the codes 9
right now that combining them together, there's some 10 duplication that has to be done because some of them 11 use the same atmospheric transport models in the 12 codes, but yet I have to maintain them in three 13 different codes, whereas if I put them all together in 14 one atmospheric transport engine, as it were, then I 15 would only have to make changes to that one engine, 16 and then that data could be passed for, say a mid-17 field calculation, a near-field calculation, or a far-18 field calculation.
19 MEMBER BALLINGER: Yeah, but the sort of 20 workload to do this is definitely not linear. Once 21 you get out of scripts, it's non-linear and it becomes 22 an enormous task for which there are unknown unknowns, 23 so to speak.
24 MS. WEBBER: So, I'm wondering if we 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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20 should transition to John's presentation, because I 1
think he's going to talk about some of these things.
2 Would you like me to stop sharing my screen, and at 3
least we'll transition to John's presentation?
4 MEMBER REMPE: That sounds like a good 5
idea, Kim.
6 MS. WEBBER: Okay.
7 And then if you want to continue with 8
questions, we can do that.
9 MEMBER REMPE: Do any members have any 10 other questions while we're in transition mode here?
11 PARTICIPANT: No, Joy. Thanks for 12 asking.
13 MEMBER REMPE: Thank you.
14 MR. TOMON: So, does everybody see my 15 screen now?
16 (Chorus of aye.)
17 MR. TOMON: Okay, thanks. So, good 18 morning. As Kim said, my name is John Tomon and I'm 19 the Chief of the Radiation Protection Branch of the 20 Office of Research. And this morning I'm going to 21 discuss Volume 4, the Licensing and Siting Dose 22 Assessment Code Plan, that my staff developed in 23 collaboration with the program offices and several of 24 our code contractors and developers.
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21 Volume 4, Licensing and Siting Dose 1
Assessment Codes, this report describes the vision and 2
strategy to achieve readiness for non-light water 3
reactor designs for the Licensing and Siting Dose 4
Assessment Codes, and is a living document.
5 It provides an overview of the technical 6
issues related to the different non-light water 7
reactor design technologies that warrant code 8
development, modifications, and/or literature reviews.
9 The report is generally oriented towards 10 generic activities that benefit all non-light water 11 reactor designs, while ensuring that the codes 12 continue applicability for the current light water 13 reactor fleet.
14 MEMBER BROWN: Can I ask a question? This 15 is Charlie Brown again.
16 MR. TOMON: Sure.
17 MEMBER BROWN: I had just backtracked to 18 the -- you can keep this slide up -- back to the 19 earlier one where you're talking about -- let me 20 think, did I get this straight -- with the non-light 21 water reactors, I'm trying to get a handle between 22 light water reactor and non-light water reactor when 23 we talk about atmospheric transport dispersion, all 24 that other type of good stuff you all want to develop.
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22 Are the characteristics of the non-light 1
water reactors, in terms of their particulate or their 2
fuel constituency or appearance, that change what 3
we've done in the light water reactor world?
4 MR. TOMON: Well, in some -- as we're 5
going to talk to later -- in some of the slides, some 6
of the non-light water reactor designs are saying that 7
if there are radionuclides that are induced into 8
environmental source term, they could be of a 9
different particulate size typically different than we 10 currently use in the 1-to-10 micron range for the 11 current atmospheric transport and dispersion codes.
12 They could be down in the nanometers, 13 which could have a different result on doses. So, 14 there is that aspect.
15 And then there's the other aspect, that 16 some of the non-light water reactor water reactor 17 designs are using different -- not as far exclusionary 18 of boundaries and emergency planning zones as the 19 current light water reactor fleet -- and so in that 20 regard some of our atmospheric transfer codes, because 21 they were built kind of rigidly for specific purposes 22 of the near-field, the mid-field, and the far-field, 23 there are certain attributes and correction factors in 24 some codes that would be applicable and would want to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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23 be used by the non-light water reactor designers and 1
reviewers for the near-field, that maybe isn't a 2
function of the mid-field characteristics.
3 So, to that end, that is another reason 4
why we kind of wanted to combine at least all of these 5
codes, and specifically into engines and in the 6
atmospheric transport phase, so that you could choose 7
from, and maybe have available, those correction 8
factors that are available in one code right now in 9
the specific code design available to all the codes to 10 do all the calculations.
11 MEMBER BALLINGER: This is Ron again. I 12 think we're dealing with that with NuScale right now.
13 No?
14 MR. TOMON: Yes, sir. Yeah, typically 15 using, for the exclusion area boundary and the low-16 population zone, the PAVAN Code, it doesn't take into 17 account building wake effects and corrections like 18 that.
19 And so, they wanted to use -- with the 20 ARCON Code, which is for control room habitability, 21 they wanted to use corrections that were used in that, 22 but that's not built in to the PAVAN Code.
23 So, as a result, they have to do 24 additional work, or code work, to make these 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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24 corrections work. So, that's where we felt combining 1
the codes would be beneficial for all, both the 2
licensees and the reviewers.
3 MEMBER REMPE: But now, we saw from Kim's 4
slide that the near-field equations have now been put 5
into MACCS. Right, John?
6 MR. TOMON: I know they evaluated it. I'm 7
not sure. We've been working with our counterparts in 8
the other branches, and I'm not sure if and how 9
they've been completely implemented into MACCS.
10 But we are going to continue to work with 11 them in that, so that when we combine these, any 12 lessons learned they learn from that. We're not going 13 to try to reproduce the wheel in that regard, but use 14 what they've already done into our codes, in and of 15 itself, for the reviewers that need it for this 16 purpose.
17 MEMBER REMPE: Okay. I thought that they 18 had the box that it was completed. Maybe I misread 19 the chart for -- or I didn't remember correctly.
20 MS. BLOOMER: Can I answer that? Hi, this 21 is Tammy Bloomer.
22 MEMBER REMPE: Yes, please do.
23 MS. BLOOMER: So, I'm the Branch Chief for 24 the Accident Analysis Branch. We work through the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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25 MACCS code with Sandia.
1 And the chart that you're referring to, we 2
did an assessment of the applicability of MACCS for 3
near-field ATD modeling, and that is what was 4
completed.
5 The incorporation of the calculations into 6
MACCS is not yet completed, and we will have those 7
calculations identified and the models prepared by the 8
March time frame, 2021, and incorporated into MACCS 9
shortly thereafter.
10 MEMBER REMPE: Great. Thank you for the 11 update.
12 MR. TOMON: Any additional questions, or 13 shall I go on?
14 MEMBER BROWN: Yeah. This is Charlie 15 Brown again. Just trying to get a better handle on --
16 you keep talking about consolidating codes, making 17 them easier to use and all that type of stuff.
18 MR. TOMON: Yes, sir.
19 MEMBER BROWN: Again, in the light water 20 world, as well as the non-light water world, 21 fissionable material is fissionable material. They're 22 the same, kind of. So, you know what those are.
23 But irradiated materials that could get 24 dispersed in an accident condition are going to be 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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26 different in many circumstances for the non-light 1
water reactors.
2 I haven't heard you talk about how you 3
come up with characterizing these materials, that we 4
don't even know what they all are yet for the non-5 light water reactors, and how your codes will be 6
amenable to incorporating those.
7 MR. TOMON: And as we're going to let to 8
later on when I talk about some of the tasks in 9
Volume 4 and some of the codes, that is one of the 10 things we're working on.
11 For example, right now we have, for light 12 water reactors to those fission products and those 13 activation products as you were talking about, we have 14 a code that similarly does this for, and is released 15 for what we consider normal effluent source terms for 16 light water reactors for both pressurized and boiling 17 water reactors, the GALE code.
18 It takes into account the activation 19 products, corrosion products, and we then use that as 20 our source term input to the NRC dose code, combined 21 with the LADTAP code, to do dose assessment. That is 22 one of the issues that we have.
23 And we're working with our partners, our 24 radiation protection code assessment contractor, PNNL, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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27 and their work with source terms with the National 1
Reactor Innovation Center, to come up with what would 2
be a good source term, or what's the best way to 3
develop a source term to encompass all these 4
activation products that we might see from these 5
various non-light water reactor designs. And again, 6
we don't have a firm direction on whether that's going 7
to be just some generic module that just allows the 8
user to import this, or we're going to actually -- but 9
we are looking at operational data where we can find 10 it, to see if we can actually hard wire maybe some of 11 these values into the codes to begin with, so that the 12 user can select, versus having to use user-defined 13 inputs.
14 MEMBER BROWN: Okay, so if I hear you 15 right, what you're saying, you're trying to roll all 16 this stuff up in the source term parts of these codes.
17 MR. TOMON: Yes, sir. Yes, sir.
18 MEMBER BROWN: Okay. Thank you.
19 MEMBER REMPE: And say that again, because 20 in my mind I would assume you'd take something from 21 the MELCOR evaluations of each technology, as a base 22 that would be put into your codes, as are the MACCS, 23 if -- with what I'm kind of suggesting.
24 And then the user would say, okay, it's 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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28 only at 25 percent power when it had the release, and 1
they would do whatever they wanted to do. And now, 2
you're thinking you're going to get it from someplace 3
other than MELCOR?
4 MR. TOMON: No. I mean, there's going to 5
be multiple sources that we envision getting this data 6
from. MELCOR and working with the staff over at the 7
Accident Analysis Branch and the Severe Accident 8
Branch, we envision getting MELCOR data typically 9
similar to what we use right now in the RASCAL code, 10 where that data from MELCOR is hard-wired into RASCAL, 11 and the user does not have to select specific 12 pressures or temperatures.
13 They're asked a series of questions, to 14 come up with a rapid dose assessment characteristic 15 based upon some other inputs that they put in.
16 So, again, we envision that the source 17 term module would include inputs from both MELCOR, 18 inputs from operational data, if there is any 19 available, specifically because when you look at a 20 normal effluent source term from GALE -- like the GALE 21 code puts out for pressurized and boiling water 22 reactors -- that's mostly operational data that it 23 includes for the reactor cooling source term.
24 So, we envision multiple sources going 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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29 into developing the source term module. But we 1
already have that in for P's and VWRs, but we have 2
them in separate places for different things, for 3
different codes.
4 So, where we envision is to combine them 5
all together into one source term engine, that would 6
then be used with the other engines in the code, to 7
get the outputs that the user desired.
8 MEMBER REMPE: Okay, so you might say for 9
the other operational data, you might have a 10 circulating activity, or something that's been fine-11 tuned, or something like that. But from the core, 12 basically -- of course, how old the core is and things 13 like that, that would come from other analysis results 14 from --
15 MR. TOMON: Yep.
16 MEMBER REMPE: -- within the NRC complex.
17 Got it.
18 MR. TOMON: Yes, ma'am. Okay. Anything 19 else, or shall I continue?
20 MEMBER REMPE: Please go on.
21 MR. TOMON: Okay. So, in the next slide, 22 when the staff on the Radiation Protection Branch and 23 our code developers and contractors started the 24 process to think about making our codes ready for non-25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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30 light water reactor technologies, we sought out 1
various sources of information, including the other 2
three volumes that Kim discuss earlier for Strategy 2, 3
to identify the various non-light water designs that 4
the dose assessment codes would need to be prepared 5
for.
6 As we looked further into the non-light 7
water designs, we further categorized them into 8
further generic classes of non-light water reactor 9
designs for Volume 4, to include molten salt reactors, 10 high-temperature gas cool reactors, liquid metals, 11 cool fast reactors, and several stationary and 12 transportable micro-reactor designs.
13 MEMBER REMPE: So, could you stay on that 14 price? Like -- when is the soonest that you, the NRC, 15 would estimate you'd have a plan up and running, where 16 you might be concerned about the need to use these 17 codes for emergency response guidance?
18 MR. TOMON: Well, the emergency response 19 guidance I would assume -- I know we have the Oklo 20 application in-house, which came in in March, so I 21 would need somebody to back me up on that. I would 22 think we're looking at three to five years to actually 23 have some sort of source term analysis that we could 24 put into our source term module for accident 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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31 scenarios.
1 But by the same token, we would also need 2
from the dose assessment and licensing siting space, 3
we would also need to look at the normal reactor 4
effluent releases that are going to happen during 5
normal operation.
6 And as far as I know right now, we've been 7
in contact with our counterparts over in NRR, and from 8
the initial application from Oklo, there's not a 9
really good environmental source term they have from 10 both an accident scenario, or from a normal source 11 term scenario, included in their application.
12 So, right now I don't know a firm date 13 that I could give you, but I would say probably three 14 to five years.
15 MEMBER REMPE: So, on Page 36 out of 53 of 16 your report, you have here, and I quote, non-LWR 17 plants are not expected to be operational within five 18 years at the earliest. Now, today you've said three 19 to five years. And so, is that just an updated 20 response since you wrote the report?
21 And then, I'd note that yes, you're right 22 about the circulating activity is important for siting 23 and licensing, but in some of these advanced reactors, 24 but the gas reactor, the circulating activity may be 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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32 important for a lot of things, because it takes a lot 1
to get the core up to where you have accident 2
releases.
3 So, I would think this is something that 4
would be used again for other evaluations that would 5
require like MELCOR, not just your codes.
6 MS. WEBBER: Joy? On the timing piece, so 7
we're constantly adjusting our priorities, given what 8
we know of applicants potentially making submittals.
9 And so, the fact that the report might say three to 10 five years and John is telling you five years, is 11 symptomatic of that dynamic environment.
12 And so, I think we're trying to do the 13 best that we can to be ready. And so that's where we 14 are right now.
15 MEMBER REMPE: It's just interesting how 16 fast it's moving up.
17 MS. WEBBER: Oh, I know. It's a very 18 dynamic fast-paced environment that we're all feeling.
19 MEMBER PETTI: So, I have a question.
20 John, is it fair to say that the biggest concern 21 technically with all these codes, besides the 22 modernization and the consolidation, is the ability to 23 accurately calculate low EPZ results, for instance, 24 where the site boundary is really tight, and making 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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33 sure that the tool can calculate that accurately, 1
given how so many of them are hard-wired for large 2
light water reactor-type sites.
3 MR. TOMON: Yes, that's correct.
4 MEMBER PETTI: Is this the biggest thing?
5 MR. TOMON: Yes, that's one of the biggest 6
things. I mean, some of the codes -- and I was going 7
to speak to this a little later -- some of the codes, 8
as written right now, are semi-flexible, in that while 9
they're written for the large light water reactors, 10 they will allow you to use user-defined 11 characteristics.
12 For example, the SNAP/RADTRAD code, it's 13 more labor-intensive for both the applicant and the 14 user to come up with the source term at the release 15 fractions and timing sequences for their reactor, than 16 doing a typical -- what's hard-wired into the code 17 right now, a dropdown selection of a pressurized water 18 reactor or boiling water reactor inventory, and the 19 release fraction and timing sequences.
20 So, some of the codes are that way and 21 they're going to be used in that specific code; the 22 SNAP/RADTRAD code is written in Java and the transfer 23 of information is very much along the lines of what we 24 talked about being from input and output in our code 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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34 modernizations strategy. So, yes.
1 So, it will be more labor-intensive. Some 2
of the codes can do it right now, but that is a big 3
issue and concern in getting these codes ready so that 4
both the applicants or, in our case, just the 5
reviewers, have the tools available. They don't have 6
to go to five different places. It's all available at 7
one place that they can do it. And if possible, hard-8 wired in, and if not, at least at the minimum, be 9
something that they could import and bring into the 10 code as a user-defined spectrum. But the goal would 11 ultimately be to have these as hard-wired inputs into 12 the code, that they can select from in multiple 13 choices, or multiple selection options.
14 MEMBER PETTI: All right.
15 MR. TOMON: Yes. Okay, so the regulatory 16 needs for dose assessment codes. So, with the 17 assistance of the program offices, we then identified 18 specific dose assessment computer codes or tools that 19 the NRC staff uses to perform independent assessments 20 and confirmatory calculations, with respect to the 21 various regulations in the Code of Federal 22 Regulations, and NRC Regulatory Guides.
23 In Volume 4, we grouped these dose 24 assessment codes based upon two areas. First was 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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35 based upon the source terms -- severe accident, design 1
basis accident, the normal or routine effluent 2
releases and decommissioning -- and also based upon 3
the types of reviews that are done for them, whether 4
it's dose consequences, siting and environmental 5
reviews, and decommissioning reviews.
6 The staff also determined that these dose 7
assessment codes would have to be updated for the 8
various non-light water reactor designs and phases, 9
based upon the availability of the resources and the 10 time frame for the various non-light water reactor 11 applications.
12 Case in point, as was already brought up, 13 we've already been in discussions with NRR about the 14 Oklo application and trying to stay in tune to what 15 needs to be done now ahead of time, prior to doing any 16 other of our phase approaches.
17 That application is at hand right now.
18 But as of right now, as I said, there's no 19 environmental source term that they have in their 20 application.
21 Our phase approach. We are considering in 22 the near-term, now through the next five years, an 23 intermediate phase, five to ten years, and a longer-24 term phase greater than ten years, with the ultimate 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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36 long-term goal of reducing the current ten-plus 1
license and siting dose assessment codes down to one 2
or two codes that accomplish the same regulatory 3
functions as all the existing ten codes currently do 4
now.
5 MEMBER REMPE: John, could we stay on that 6
prior slide? In the report I really like that you 7
finally describe what the different tools do, and 8
there was clearly a lot of overlap.
9 What I wasn't sure of after reading the 10 report was how many other agencies use these various 11 different tools.
12 MR. TOMON: Meaning federal agencies, or 13 federal and state agencies?
14 MEMBER REMPE: What I'm really looking 15 for, is there any -- like we know that MACCS, and even 16 MELCOR actually, have a users group that helped 17 contribute to activities related to co-development and 18 maintenance.
19 Are there any codes here that have other 20 organizations that are helping to support NRC in 21 maintaining and developing these codes?
22 MR. TOMON: Well all of these codes, in 23 one form or another, are codes under the Radiation 24 Protection Code Analysis and Maintenance Program 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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37 (RAMP). So there are user groups for all of these 1
codes, and RAMP not only includes these NRC dose 2
codes -- there's about 10 listed here -- but there's 3
also another five to six codes that are included under 4
RAMP.
5 So the user group has a wide breadth of 6
both international and state and local agencies, other 7
federal agencies, and the codes like the RASCAL code, 8
their user group includes the state and local 9
officials who are decision-makers for protection of 10 action guidelines.
11 Licensees are also included in the RAMP 12 user group. And we do get contributions from them.
13 We do solicit at our two RAMP meetings, input and 14 feedback from the users groups. We do it not only at 15 those meetings, but we also try to do it throughout 16 the year.
17 For all these codes, we routinely have 18 email help lines that they can ask questions and make 19 recommendations and inputs for improvements to the 20 code. So the RAMP is really the mechanism by which we 21 do our outreach for most of these codes and get input 22 and feedback on these codes.
23 MEMBER REMPE: So again, I'm still 24 struggling with my question that I raised with Kim 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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38 earlier, about why not just go to MACCS and have a 1
simplified option? And I'm still not sure I've got a 2
good answer to that question.
3 Aren't the answers that some of these 4
other agencies are really pushing no, keep these 5
codes? I'm still struggling with why we can't --
6 because at the earlier meeting we discussed this, it 7
was not just ruled out that you just can't do it, 8
which is what this report tends to imply.
9 MR. TOMON: Well some of the codes, like 10 specifically the RASCAL code, as we said before in the 11 past, and I know it's not the only answer, but the 12 RASCAL user group is a unique group. They are 13 typically local and state officials that are 14 protective action decision makers, that are trying to 15 make decisions based on real-time accidents, or real-16 time events in the plant, using real-time meteorology, 17 both observational and forecast dated, to make their 18 protective action decisions based upon the pre-19 existing emergency plans they have.
20 Usually, in most of the cases, most of 21 these first responders are not very technically savvy 22 in some cases in the reactor physics world and the 23 nuclear plant world. They are really just looking at 24 what is the environmental source term, what is that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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39 term that's leaving containment that can be 1
transported downwind, and what do I have to do to 2
protect my people?
3 Most of our state and local officials 4
don't particularly want to just go with what the 5
licensee says, even though the licensee is -- we do 6
confirmatory analysis at the operations center and the 7
incident response
- center, to verify what the 8
protective action recommendations are and the 9
decisions are.
10 Typically the state and local officials, 11 those decision-makers, sit there, want to make some 12 sort of back-up calculation, confirmatory calculation, 13 to what they're getting from the licensees in their 14 locality. So they will run RASCAL.
15 But again, RASCAL, they don't have that 16 technical background and savvy to know what this plant 17 pressure or this plant temperature, or this 18 containment pressure means. They don't know that.
19 But what RASCAL does, it asks them very 20 simple questions based on hard-wired MELCOR data 21 that's already in, and scale data for the core 22 inventories, that we ask them some specific questions, 23 they make some very minor inputs, weather is 24 automatically downloaded for them, and that they can 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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40 run a relatively quick, scientifically defensible, 1
calculation, that they can then look at what the 2
licensee is telling them, and confirm it one way or 3
another, same way as the NRC is doing that, and the 4
same response.
5 MEMBER REMPE: So again, I'm still puzzled 6
why you can't take MACCS, put a simplified option with 7
the hard-wired data and the questions required, since 8
it's coming from other codes, and do something like 9
that.
10 Because the report says it's a common 11 misconception. Well it seems to me still that it's an 12 attitude of whether I want to do it this way or the 13 other way. And I'm not seeing that it's impossible to 14 do.
15 MR. TOMON: I guess I'm not saying it's 16 impossible. But the paradigm for the user communities 17 are totally different. And building off inputs from 18 the MACCS code, I mean we intend as a staff to 19 leverage work done, because resources, as everybody 20 always knows, resources are always tight all the way 21 around.
22 We don't plan to do things in a vacuum, 23 not working with what work on MELCOR is being done, 24 what work in scale is being done, and what work in 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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41 MACCS is being done.
1 But the user community typically -- I know 2
they came up with a MACCS-lite, as it were, many years 3
ago, a fast-running MACCS, but for whatever reason --
4 and one of the reasons I think I remember hearing but 5
don't quote me on it -- was that the user community, 6
meaning the state and local officials, found it way 7
too difficult to use, as compared to codes like the 8
RASCAL code, that asked very simple questions to do 9
it.
10 Ultimately, I guess if you look at it --
11 to get to your statement, Joy -- they basically do the 12 same things. They have the same inputs from MELCOR, 13 the weather runs are much less because they do real-14 time data in RASCAL.
15 But the way the format that's used in 16 RASCAL, is something that the user community kind of 17 expects, is kind of used to, and it's not difficult 18 for them to make the decisions and recommendations, 19 based upon the outputs of the RASCAL code.
20 (Simultaneous speaking.)
21 MEMBER REMPE: I just think we're getting 22 back to what we heard at the prior meeting then, that 23 if you look at it in the long-term -- and again, you 24 need to be very careful about the customer and what 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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42 they want -- but you could have another MACCS-lite 1
that would download the data very rapidly.
2 And it might be a more efficient use of 3
resources if you looked at the long-term, which is 4
kind of where we got to at the prior meeting. And 5
none of that discussion actually shows up in this 6
report.
7 And that's where I was confused, because 8
I just can't see a reason that it couldn't be done.
9 I mean the report's pretty strong. It says this is a 10 common misconception. Well it's not a misconception.
11 It's just an approach that you've selected. Right?
12 MR. TOMON: Yes. And I guess getting to 13 your point, that is something we could look to in the 14 long-term, maybe 10-plus years. Because originally 15 when we talked about it -- in the later slides when I 16 go on -- this approach for code consolidation and 17 modernization trying to get them in, as I said 18 earlier, we're trying to get down to one or two codes.
19 And ultimately, the goal would be to get 20 down to one. And there's always been some discussion 21 in a group with our contractors right now, that 22 loading something like RASCAL into this one code that 23 did everything that these 10 codes does, but just have 24 it so that the RASCAL code would be something that 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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43 just the emergency response the immediate responders 1
would use, that might not be something we can do up 2
front, and it might be something we can do later on 3
down the line, to get it into one code, as it were.
4 So I mean we're not -- I guess the answer 5
is I'm not saying that we are completely ruling out 6
something like that. But for now, we see as keeping 7
RASCAL and kind of MACCS, making them feed off each 8
other from what they do, and even in the point, even 9
if we get to a point later on, maybe 10 years down the 10 road, that there's some way to combine, that's not out 11 of the realm of possibility. But right now that's not 12 currently in our plan.
13 MS. WEBBER: Yeah, can I just add 14 something quickly? I think John characterized it 15 pretty well. But so Joy, it's not impossible to do.
16 We could do it. We have chosen to take this route, or 17 the route that's represented in Volume 4.
18 Part of it is that we have an internal-to-19 the-NRC community that use these different codes at 20 different times. And so to provide codes that the 21 individual communities who use all these codes at the 22 bottom, different people use them at different times, 23 I think that's a service that we need to provide.
24 And so to introduce potentially a new code 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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44 with a different set of dynamics plus additional 1
costs, is something that maybe we could do in the long 2
run, but it may not support our near-term activities 3
with applicants coming through the door in the next 4
few years.
5 MEMBER REMPE: So I get what you're doing.
6 But I mean if you looked at the long-term and the cost 7
of maintaining all of these different codes, or even 8
what you end up with the consolidated version versus 9
going to the long-term goal of having MACCS, 10 downloading stuff from MELCOR and immediate data 11 coming from the site, the long-term cost to the agency 12 might be lower.
13 But again, how you get funding allocated 14 from Congress on an annual basis or users, that kind 15 of thing has to be considered. But I think the 16 report's not accurately reflecting that this was an 17 approach selected because of whatever. Because it 18 implies it's a misconception, you can't do it. And I 19 think that needs to be corrected.
20 MS. WEBBER: Okay. Thanks for the 21 comment. I wonder if we should move on to the next 22 slide.
23 MEMBER REMPE: Please do. I'll quit 24 whining about it. But thank you for also being a 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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45 little bit more forthright about it than what I saw in 1
the report.
2 MS. WEBBER: Okay, thanks.
3 MR. TOMON: So continuing on, as shown in 4
the bottom of the previous slide and in this figure 5
from Volume 4, we are looking towards the possibility 6
of having to make ready 10 licensing siting dose 7
assessment codes for the various non-LWR applications.
8 Included in these codes are the 9
radionuclide transport removal and dose estimation 10 code (RADTRAD), the control room habitability code 11 (HABIT), the atmospheric relative concentrations and 12 support of control room habitability (ARCON), the 13 ground level air concentrations for accidental release 14 codes (PAVAN), the gaseous and liquid ethylene code 15 (GALE), the normal effluent dose assessment and siting 16 code (NRCDose), the normal relative air concentrations 17 and relative disposition factors code (XOQDOQ), the 18 radioactive material transport dose assessment code 19 (RADTRAN), the radiological system for consequence 20 analysis code (RASCAL), the decommissioning and 21 decontamination code (DandD), and the residual 22 radioactivity code (RESRAD).
23 In Volume 4, we also included discussions 24 on other codes that either non-light water reactor 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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46 designers are considered using in their applications, 1
such as the Generation 2 code, or the GEN2 code, or 2
codes which have inputs to the codes on this slide, 3
such as the dose coefficient package code (DCFPAK),
4 the SCALE code, the MELCOR code.
5 In the next few slides, I'll briefly 6
discuss the purpose of each of these codes for 7
licensing and siting purposes.
8 MEMBER BROWN: Can I ask another question 9
that just popped up as you read through all that?
10 MR. TOMON: Mm-hmm. Yes, sir.
11 MEMBER BROWN: Part of your -- if you go 12 back to that earlier slide, you talked about 13 consolidation and modernization. So you must have 14 listed a dozen codes or so.
15 MR. TOMON: 10, sir. Yes.
16 MEMBER BROWN: 10, okay, I was off a 17 little bit.
18 MR. TOMON: No problem.
19 MEMBER BROWN: So I presume when you talk 20 about consolidating, you want to bring these 21 together --
22 MR. TOMON: Yes, sir.
23 MEMBER BROWN: -- in their operations.
24 Isn't there a danger in that? I mean it's nice many 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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47 times to have a lot of eggs, as opposed to having one 1
big basket. If something has to be worked on or done 2
in an overall consolidating code, it takes out of 3
service all of them.
4 So I've just been thinking about that 5
after I looked at your introduction stuff and 6
everything else.
Have you taken that into 7
consideration?
8 I understand the idea of trying to not 9
have to go piecemeal, but consolidation could also add 10 complexity and reduce usability, if something goes 11 wrong and you've got to go correct something in one of 12 the modules or sub-modules or whatever. The whole 13 code is out of service.
14 MR. TOMON: Well the goal was -- and one 15 of our phases in our goal was to do the atmospheric 16 transport consolidation, the ARCON, PAVAN and the 17 XOQDOQ codes.
18 And in that, one of our goals -- and 19 you're right, and we wanted to do it as a proof of 20 concept to see if we developed that one engine, 21 because they all use straight-line Gaussian plume 22 models, that we still met the existing requirements 23 for the different regulatory guides and the different 24 needs of those codes, but that they were consolidated 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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48 into one module, so that -- because currently right 1
now, codes like ARCON just got updated.
2 But some of the codes have not been 3
updated in years. And to do changes, or to do stuff 4
to them, is more labor-intensive. So what we figured 5
is if we did this proof of concept with this one 6
engine -- we called it the atmospheric transport 7
engine -- that would be our first to see -- and it's 8
a natural kind of evolution of the codes, because they 9
all use the same models underneath for calculational 10 purposes, with different varying correction factors in 11 there.
12 So we're going with the assumption that 13 that will be our first proof of concept, and we'll 14 learn from that as we move further on with the other 15 codes. But we don't foresee it -- I mean I guess we 16 didn't foresee it as a big stumbling point in taking 17 down all the other codes and taking us out of work in 18 that particular point in time. Because we -- go 19 ahead.
20 MS. WEBBER: I was just going to say, plus 21 you wouldn't take those old codes out of service until 22 you got a working new version of the consolidated 23 models.
24 MR. TOMON: That's correct. We would make 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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49 sure that the proof of concept works and meets the 1
needs of the program offices and before we would 2
sunset those codes, as Kim is saying.
3 MEMBER BROWN: Yeah, but once you have a 4
working model that's been blessed, you're inevitably 5
going to want to make changes to it. And when it's 6
taken out of service to make changes, that takes out 7
of service everything.
8 MS.
WEBBER:
I think with code 9
development, as I understand it from a limited 10 perspective, they don't take out a service -- the 11 code -- while they're working on the next version.
12 So as I understand it, there's a working 13 version, regardless of what's in that code and the 14 models and phenomena modeled in those codes. And then 15 as they're building new functionality or making 16 changes to the code based on bugs that have been 17 identified, they'll redo the validation for the code 18 before they release it, so that it ends up being a 19 working code.
20 MEMBER BROWN: Okay. Thank you, Kim.
21 MS. WEBBER: Yeah, sure.
22 MR. TOMON: So my next slide depicts the 23 safety and environmental review codes that are used 24 for siting purposes for design basis accidents.
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50 The RADTRAD code is used by the NRC staff 1
and applicants to calculate doses to demonstrate 2
compliance with the nuclear plant siting criteria at 3
the exclusion area boundary in the low-population 4
zone. It is also used to calculate occupational 5
radiation doses within the control room and/or other 6
offsite emergency facilities.
7 The code is joined together at the front 8
end, with the symbolic nuclear analysis package, is 9
commonly referred to as SNAP/RADTRAD.
10 The PAVAN code is used to estimate 11 relative ground-level, short-term air concentrations 12 resulting from releases of design basis accident at 13 the exclusion area boundary and the outer boundary of 14 the population zone.
15 PAVAN uses a straight line Gaussian plume 16 model that assumes a release rate is constant for the 17 entire period of the release.
18 The ARCON code is used to calculate short-19 term accident air concentrations in support of control 20 room habitability assessments, as described in Reg 21 Guide 1.194. The code uses a straight-line Gaussian 22 model that assumes constant release rate.
23 ARCON also implements building wake, low 24 wind speed dispersion algorithms, and ground level and 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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51 elevated source release modes.
1 The next code I will briefly discuss is 2
the HABIT code, which is used to examine control room 3
habitability following a postulated release of toxic 4
chemicals, based on regulations in Reg Guide 1.78.
5 The code consists of four FORTRAN codes 6
connected through a common graphical user interface.
7 These codes include the external transport computer 8
code EXTRAN, which is a Gaussian puff dispersion 9
model, the control room chemical code CHEM, the 10 Environmental Protection Agency's dense gas dispersion 11 code (DEGADIS), and the Department of Energy's denser-12 than-air release computer code SLAB.
13 This slide shows the relationship of dose 14 assessment codes which are used for normal effluent 15 releases and transportation reviews. The GALE code, 16 as I spoke to before, which is used to estimate annual 17 routine releases of radioactive gases and liquid 18 effluence from pressurized and boiling water reactors, 19 based upon the regulations in Reg Guide 1.112, the 20 NRCDose code, which is a software suite that contains 21 a common graphical user interface that runs three 22 FORTRAN codes -- GASPAR, LADTAP and XOQDOQ code --
23 working together, these codes are used to estimate 24 offsite doses from liquid and gaseous radioactive 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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52 releases from routine nuclear power plant operations, 1
and implement those low-as-reasonably-achievable 2
requirements of Appendix I of 10 CFR Part 50.
3 The LADTAP code, which implements the 4
liquid pathway models in Reg Guide 1.113, and when 5
combined with the normal liquid effluent from the GALE 6
code, will calculate the annual doses from routine 7
releases of reactor coolant effluence per Reg 8
Guide 1.109.
9 The XOQDOQ and GASPAR codes implement the 10 atmospheric pathway models in Reg Guide 1.111, and 11 when combined with normal gaseous effluent source term 12 from the GALE code, GASPAR will calculate the annual 13 doses from routine releases of gaseous effluence per 14 Reg Guide 1.109.
15 Finally, the RADTRAN code is used to 16 estimate doses from routine and accident scenarios 17 involving the transportation of radioactive material, 18 including spent nuclear fuel.
19 The code is used for environmental impact 20 statements pursuant to the requirements of the 21 National Environmental Policy Act and NRC and 22 Department of Transportation regulations.
23 Dose consequence codes. The RASCAL code 24 is an emergency response code, as we've already talked 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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53 about, used to perform independent dose consequence 1
projections during the initial plume phase of 2
radiological incidence and emergency, including severe 3
accidents.
4 As I spoke to before, it was designed to 5
provide scientifically defensible dose projection, 6
within 15 minutes of the occurrence of an event to 7
support protective action decision-makers at the state 8
and local level, as well as the NRC staff.
9 While very similar to the MACCS code, each 10 of these codes serves a different user community, with 11 different expectations.
12 For example, as I spoke to earlier, the 13 RASCAL users typically are first responders, state and 14 local personnel, running many different what-if 15 scenarios during the plume phase of an event.
16 RASCAL uses automatically downloaded, 17 real-time observational and forecast meteorological 18 data from the National Weather Service, combined with 19 a limited number of user supplied plant inputs, to 20 provide dose projections to compare to the EPA's 21 protective action guidelines.
22 MACCS users are typically emergency 23 planners and dose-consequence analysts who use the 24 code for facility siting purposes. Additionally, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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54 MACCS codes require a significant number of weather 1
trials and plant inputs, and can require several hours 2
to days to set up and run calculations. MACCS 3
calculations also extend to the intermediate and long-4 term phases of an event.
5 Decommissioning codes. The staff decided 6
to, before thinking when developing Volume 4, to 7
include decommissioning codes as part of our phased 8
approach for our non-light water reactor code 9
readiness strategy.
10 Codes such as decontamination and 11 decommissioning (DandD) and the RESRAD family of 12 codes, are used by licensees and the staff in license 13 termination surveys. They are briefly discussed in 14 this volume to bring attention to the entire lifecycle 15 of non-light water reactors, not just siting, 16 licensing and operations.
17 Their need to be evaluated may become more 18 apparent in the longer term implementation plan, i.e.,
19 greater than 10 years.
20 Research and other codes. Finally, the 21 staff also looked at several other dose assessment 22 codes that are either similar in function to many of 23 the licensing and siting codes already discussed in 24 the previous slides, or are codes which are used as 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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55 inputs to the licensing and siting codes.
1 Such codes at the ones that are similar to 2
the ones we've already talked about was the 3
Generation 2 computer code, or the GEN2 computer code, 4
which models atmospheric releases of radioactive 5
materials to the environment, and had a similar dose 6
assessment and points with several of the licensing 7
and siting codes previously discussed.
8 MEMBER REMPE: John, I meant to ask you 9
earlier, but what would you use for assessing release 10 from a reactor that's being transported either by rail 11 or by airplane?
12 MR. TOMON: Well that's where the RADTRAN 13 code on the couple of slides back would come into 14 effect. And right now that scenario is not in there, 15 because we would have to add that source term to the 16 RADTRAN code. But it would be the RADTRAN code.
17 That's the purpose of the RADTRAN code.
18 MEMBER REMPE: Okay. Yeah, and that's 19 what I thought when I read the report. I guess I 20 couldn't hear it during this session. I might have 21 missed it. Thank you.
22 MR. TOMON: Yes. The Dose Coefficient 23 Package File, or DCFPAK, includes nuclear decay data 24 and dose and risk coefficients for exposure for each 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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56 of the 1,252 radionuclides addressed in ICRP 1
Publication 107. Parts of DCFPAK are currently used 2
in the RASCAL code, NRCDose, and the SNAP/RADTRAD 3
codes.
4 Finally, the staff also included a 5
discussion of the scale and MELCOR codes in Volume 4, 6
because these outputs from both are currently hard-7 wired into codes such as RASCAL and SNAP/RADTRAD.
8 The staff plans to leverage work done on 9
these codes for non-light water reactor technologies 10 in our licensing and siting codes, where applicable.
11 Volume 4 Code Readiness Test. Working 12 with our individual dose assessment code developers 13 and the radiation protection computer code analysis 14 maintenance program (RAMP contractor, Pacific 15 Northwest National Laboratory), the staff developed 16 the five tests listed on this slide to prepare the 17 license and siting dose assessment codes for non-light 18 water reactor readiness.
19 These tests included looking at Code 20 Consolidation and Modernization, Task 1, code source 21 terms, atmospheric transport and dispersion models, 22 dose coefficients used, and environmental pathway 23 models used in some of the codes.
24 Code Consolidation and Modernization, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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57 Task 1. One of the first tasks that the staff came 1
upon was the number of license and siting dose 2
assessment codes, 10, and the number of different non-3 light water reactor designs.
4 The staff decided that code consolidation, 5
where possible, was an efficient means of maintaining 6
and writing the codes with the resources available.
7 Code consolidation and modernization was viewed at a 8
means to help reduce functional redundancy between 9
codes, outdated science and technology associated with 10 the design and development of the codes, limited 11 ability of the current codes to assess advanced 12 reactor designs, agency resources associated with 13 undue analysis and co-distribution efforts, and the 14 inefficiency of having to maintain multiple codes.
15 With this thought in mind, we came up with 16 a code consolidation approach with the assistance of 17 our RAMP contractor, Pacific Northwest National 18 Laboratory.
19 We developed a three-pillar approach to 20 code consolidation, including first create 21 consolidated engines. This is a set of functional 22 modules for engines that would be developed to form 23 the regulatory calculations as those performed by the 24 current suite of licensing and siting dose assessment 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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58 codes.
1 The functional engine approach improves 2
development flexibility by allowing future 3
modifications and efficient data transfer.
4 Furthermore, separating these capabilities 5
as standalone engines eliminates the code redundancy 6
and inefficiencies that currently exist.
7 Second, develop a standardized data 8
transfer schema. Using standardized data transfer 9
schema, such as extensive markup language, or XML, for 10 encoding data for each engine, would make data input 11 universal and adaptable, while making it easy to pass 12 output data between the different functional engines.
13 By using the extensive markup language as 14 a data management system within the consolidated code 15 framework, the entire system would be more robust 16 relative to the advancements in the nuclear industry, 17 and any improvements in data entry, such as 18 downloading meteorological data inputs.
19 Finally, the last pillar is to build a 20 single user interface. A single user interface would 21 be developed separate from the functional engines that 22 would interact with users and communicate with the 23 functional engines to execute user-defined commands.
24 The user interface would be designed to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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59 effortlessly guide users to the relevant code engine 1
input screens, primarily through a series of questions 2
about desired outputs.
3 The conceptual model for a consolidated 4
code. The figure on this slide is a conceptual 5
diagram of the proposed consolidated code paradigm 6
showing how the models from the existing siting and 7
licensing codes could be integrated into a new 8
consolidated code.
9 The modules within the consolidated code 10 would be grouped or characterized within this general 11 dose assessment approach. In addition, the modules 12 would be further broken down into scientific 13 disciplines, to account for the unique differences of 14 these fields.
15 The proposed consolidated code would have 16 several modules or components of each, which will 17 contain phenomenological models from the existing 18 light water reactor codes.
19 The eight modules of the consolidating 20 code include a source term including core inventories; 21 release fractions and timing sequences; an atmospheric 22 transport and dispersion modeling, to include near-,
23 mid-and far-field models; aquatic pathway modeling, 24 including
- ocean, river and lake dispersion; 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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60 environmental accumulation; human biota consequence 1
modeling; non-human biota consequence modeling; dose 2
efficients and health risk factors; and an integrated 3
dose module.
4 The second task of Volume 4 was to 5
identify the source term inputs, such as the 6
radionuclide fuel inventories, reactor coolant 7
inventories, plant design and operational data, for 8
each of the non-light water reactor designs.
9 Source terms are one of the higher 10 priority modules, because it's the first data needed 11 in the dose assessment process.
12 For normal operations, the radionuclides 13 of interest in the source term include fission 14 products, capture products, activation products 15 produced during normal operations, and the reactor 16 cooling system.
17 For accident conditions, both severe 18 accidents and design basis accidents, the primary 19 source term information will be from the work on the 20 SCALE and MELCOR codes described in Volume 3.
21 And finally the transportation source 22 term, the various non-light water reactor fuel types, 23 vary significantly from the current light water fuel 24 configurations.
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61 In addition, some of the non-light water 1
reactor designs may adopt a battery-type approach 2
where it's likely that the entire core containing the 3
spent fuel will be transported as a single shipment.
4 Therefore, the transportation source term and module 5
will need to take these issues into account and 6
consideration.
7 Some other source term considerations, the 8
radiation protection branch staff plans to work with 9
the program offices and the other co-development 10 branches and research to leverage activities from 11 Volumes 1, 2 and 3.
12 We are also working with your RAMP 13 contractor, Pacific Northwest National Laboratory, to 14 leverage their source term work and activities with 15 the National Reactor Innovation Center.
And 16 specifically we will look to leverage the work done 17 with SCALE and MELCOR codes, to estimate the 18 inventories and these fractions and timing sequences, 19 and reduction mechanisms, for the various non-light 20 water reactor designs.
21 Finally, some of our current licensing and 22 siting assessment codes, as I spoke to earlier, are 23 flexible in their current configuration, to accept 24 source terms outside of the current light water 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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62 reactor designs.
1 For example, as currently constructed, the 2
SNAP/RADTRAD code will allow users to enter user-3 defined source terms, release fractions, and timing 4
sequence. However, this is a more involved thought 5
process than selecting from current hard-wired 6
pressurized and boiling water reactor options already 7
in the code.
8 Additionally, NRCDose can allow for import 9
of user-defined source terms. However, there is 10 currently no code that will perform normal effluent 11 reactor source term calculations for non-light water 12 reactor technology, like the GALE code does for light 13 water reactor technology.
14 MEMBER KIRCHNER: John?
15 MR. TOMON: Yes.
16 MEMBER KIRCHNER: This is Walt Kirchner.
17 MR. TOMON: Yes.
18 MEMBER KIRCHNER: Some of these designs 19 will produce significant amounts of tritium. How does 20 that fit into the overall scheme that you envision?
21 MR. TOMON: In some of the later tasks we 22 do talk about that. We will have to consider both the 23 amount for the high-temperature gas cool reactor, and 24 the molten salt reactor, the tritium that is being 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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63 produced, both with the environmental pathways and the 1
dose coefficients that we use in the code.
2 So we are looking towards that. We are 3
also looking to try to get some of the operational 4
data from the molten salt reactor, to see what the 5
tritium concentrations were and what they were seeing 6
for maybe their normal tritium concentrations in the 7
plant, so that we can take that into consideration as 8
we move on and develop a source term for those codes.
9 MEMBER KIRCHNER: I'm sorry. To follow 10 on, how do you deal with -- tritium production is not 11 such an issue with our current fleet. It's a bigger 12 issue, for example, for the CANDU reactors. How do we 13 take care of it currently with the existing suite of 14 codes that you use?
15 MR. TOMON: I would have to defer to --
16 I'm not really 100 percent sure how the exact 17 mechanism we use in our codes -- I mean I know 18 typically, that typical code that you would see that 19 in the source term, or it would be included in the 20 source term would be when performing calculations 21 within the NRCDose code.
22 However, I'm not really 100 percent sure 23 of how we take that into account for the current P and 24 PWR, BWR fleet.
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64 MEMBER KIRCHNER: Yeah, it just becomes --
1 the reason I raise it, it becomes a much larger 2
concern with some of these advanced designs than we've 3
had to deal with in the past. Okay, thank you.
4 MEMBER PETTI:
So
- Walt, there is 5
international work done through the IAEA on what's the 6
state of the art tritium transport code. Because of 7
other technologies that use tritium. And so the 8
fusion program has spent a lot of time internationally 9
on the code called UFOTRI, which I think is now in the 10 IAEA database.
11 So there is a community that has looked 12 into that. They've done release experiments to make 13 sure they understand the transport and the uptake.
14 And there's a lot of data out there.
15 MEMBER KIRCHNER: Yeah. Dave, I almost 16 imagine that it would be an overlay of the existing 17 framework that John has been sharing with us, almost 18 like a side -- I hate to say a side calculation, but 19 it probably would be an overlay and you would deal 20 with it perhaps independently with other codes that 21 have been developed, as you point to in the fusion 22 community.
23 MEMBER REMPE: Could we ask for you as a 24 follow-on to maybe send us a note through Derek, John, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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65 about what is done with tritium for the current fleet?
1 MR. TOMON: Sure. I can look into that.
2 Sure, no problem.
3 MEMBER REMPE: Thank you.
4 MR. TOMON: The third module or third task 5
we have in the report involves the atmospheric 6
transport and dispersion model.
7 Most of the licensing and siting dose 8
assessments use or have atmospheric transport and 9
dispersion models, which are typically Gaussian plume 10 models. For example, ARCON, PAVAN and the XOQDOQ 11 codes use straight-line Gaussian models with different 12 correction factors, such as building wake effects, 13 wind direction, wind speed, atmospheric stability 14 cost, location of the release point, stacked downwash 15 and plume rise to adjust for the codes used.
16 As a
proof of concept for code 17 consolidation, the staff is looking to consolidate 18 ARCON, PAVAN and the XOQDOQ into a single atmospheric 19 engine and a phased approach.
20 Phase 1 would be an integrated atmospheric 21 engine that would have the capability of performing 22 near-field, mid-field, and far-field calculations, 23 thereby the user could perform regulatory calculations 24 relevant to any of these three distances.
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66 Phase 2 would involve adding capabilities 1
to the consolidated atmospheric to support non-light 2
water reactor technology sitings, such as siting in 3
remote areas with differing atmospheric stability, 4
diffusion and dispersion characteristics.
5 MEMBER KIRCHNER: John?
6 MR. TOMON: Yes?
7 MEMBER KIRCHNER: That last statement 8
doesn't kind of ring true. We have that same problem 9
with the current fleet. What would be different? It 10 might be Alaska where you haven't sited before or 11 something like that, but I would think from a 12 methodology standpoint, that's just a factor of 13 importing the local meteorological conditions, right?
14 MR. TOMON: Well, what they're -- I guess 15 what we're looking at here, and that's why it's a 16 phase 2 part of the approach, is that we're looking at 17 most of the Pasquill-Gifford calculations for 18 dispersion and diffusion were done in the middle of 19 the United States with relatively flat terrain and 20 topography back in the '60s.
21 So, I know there have been and we have 22 been in discussion with our meteorologists that we 23 work with on the PAVAN code and the ARCON code in 24 Pacific Northwest National Laboratory, that there have 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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67 been other studies that have been done in some remote 1
areas where there are those, where those dispersion 2
and diffusion characteristics might not be, the 3
Pasquill-Gifford ones might not be true to what is not 4
in the remote area, say sort of like in Alaska.
5 So, right now, we are going to work with 6
the meteorologists over in NRR to implement these 7
based upon the needs and to allow that option so that 8
we can, in this consolidated atmospheric transport 9
module, so that we can implement those as needed based 10 upon the siting in remote areas based upon what the 11 reviewers at NRR deem as appropriate or acceptable 12 then from typical ones we use right now, which are the 13 Pasquill-Gifford ones.
14 MEMBER KIRCHNER: Yeah, I just, well, I 15 guess what I'm objecting to is just that I wouldn't 16 call Oak Ridge a remote area anymore, but, you know, 17 we did an early site permit for Oak Ridge and they had 18 rather interesting meteorology there. I mean, they've 19 got -- you probably know the site, so I'm just 20 reacting to it's not a remote siting issue.
21 It's just the basic physics of the models 22 that you incorporate, but you have sites in the U.S.
23 that have some peculiarities and Oak Ridge is 24 certainly one that's, you know, prone to atmospheric 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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68 inversions, et cetera.
1 MR. TOMON: Yeah, well, what we really 2
want to do is kind of be ready for the needs of the 3
reviewers at NRR, so to listen to their needs based 4
upon what they need if the code as consolidated 5
doesn't do exactly what it does.
6 But we're hoping since we're going to this 7
kind of standard input/output XML data transfer, that 8
making changes to the code and providing updates as 9
needed with verification and validation would not be 10 a long process.
11 It would be relatively quick to do what 12 the reviewers need for different scenarios based upon 13 whether it's remote or not remote, or just because of 14 the environmental conditions of the site.
15 So, this slide is showing an example of 16 some thoughts we had for the user inputs and features 17 that could be incorporated into the atmospheric engine 18 prototype along with the data flow between the 19 interface and the engine.
20 After selecting a dispersion distance 21 model, i.e., the near, mid, or far field, the user 22 could provide source receptor inputs such as distance, 23 intake height, and direction using 2D and 3D graphical 24 displays.
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69 The user would then choose a
1 meteorological file and visualize the wind 2
distribution. The terrain data could be imported from 3
a public database such as the National Elevation 4
Dataset.
5 And once the inputs are set up, the data 6
shall be transferred using extensive markup language, 7
XML schema, to the atmospheric engine where the 8
calculations are performed.
9 After the calculations are completed, the 10 atmospheric dispersion engine would allow the user to 11 select various outputs for both reporting and plotting 12 results depending upon the needs and the regulatory 13 requirements.
14 A dose coefficient module, the fourth task 15 involved developing a dosimetry engine that has the 16 flexibility to use different vintage dosimetric models 17 and dose coefficient values, and also examining the 18 dose coefficient models with respect to aerosol 19 particle size since most of the non-light water 20 reactor and technologies could release particles 21 smaller than the one to ten micron range that are 22 currently considered for the current codes.
23 Current regulations such as 10 CFR 20 24 require that licensees use dose coefficient values 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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70 from older dosimetry models and systems. Typically 1
for the codes, the dose coefficients and dosimetry 2
models are hardwired into the code and the user has 3
few options to edit or change these values.
4 An important element of this task is to 5
design the module with an understanding of the 6
different dosimetry endpoints of siting, licensing, 7
and emergency response for non-light water reactor 8
designs.
9 The vision for the dose --
10 MEMBER REMPE: You'll have to be careful 11 because of the folks that are your users that may not 12 have the technical background to do too much, right?
13 MR. TOMON: Yes, ma'am. Yes, we'll have 14 to be careful of that, plus they'll have to -- the 15 goal would be to make it flexible, but also at the 16 same time, where necessary, add how they're using or 17 what they're using, or what they choose for different 18 dose coefficient and dosimetry models and how that 19 would affect or what -- you know, just make sure that 20 there's a warning in the system somehow along those 21 lines as well.
22 The vision for the dose coefficient module 23 is it would be a flexible module that allows the user 24 to select from Federal Guidance Reports 11 and 12 dose 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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71 coefficients used by the current regulations, as well 1
as future Federal Guidance Report dose coefficients 2
such as FGR 15.
3 Another part of this module would consider 4
options to allow the user to select aerosol particle 5
size for radionuclides.
6 The dose coefficient forms may also need 7
to be modified to account for various different forms 8
of volatile carbons such as carbon monoxide, carbon 9
dioxide, and other organic molecules, as well as a 10 modification for tritium dosimetry models for the high 11 temperature gas cool reactors and the molten salt 12 reactors.
13 Currently, the SNAP/RADTRAD code allows 14 the user to enter user-defined dose coefficients in 15 addition to the hardwired Federal Guidance Report 11 16 and 12 values.
17 The remaining dose assessment codes as 18 currently configured do not possess an option for the 19 user to select user-defined coefficient values.
20 Codes like NRCDose and RASCAL do allow the 21 user to choose between dose coefficient values from 22 different hardwired dosimetric models such as ICRP 2, 23 26 and 30, and ICRP 6072.
24 The final task in Volume 5 consists of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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72 further developing aquatic pathways, river, lake, 1
ocean dispersion, environmental accumulation, and 2
human and non-human bio consequences.
3 These tasks are in future phases because 4
they are less dependent on the non-light water reactor 5
design and fuel types, and we're considering that in 6
the five to ten-year range.
7 The task will also look to explore the 8
feasibility of radionuclide particle size behavior in 9
the environment for some of the non-light water 10 designs.
11 The task will also leverage models from 12 the Generation 2 code and the decommissioning codes 13 like RESRAD and work plan for the max mode to examine 14 deposition models to the environment.
15 Some other considerations and challenges, 16 as I stated in the beginning of my presentation, we 17 are looking to implement these tasks in phases 18 depending on several factors such as the timing of 19 non-light water reactor submittal versus code 20 readiness.
21 For example, as I mentioned before, the 22 radiation protection staff is monitoring the Oklo 23 submittal and meeting with the staff from NRR.
24 However, there is currently no source term to the 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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73 environment in the current application.
1 We also need to take into account code 2
consolidation versus non-consolidation as was brought 3
up in the meeting, which includes the availability of 4
resources, both the staff and contract farming on a 5
year to year basis for near, mid, and long-term code 6
consolidation projects, and will be a continuing 7
consideration and challenge.
8 And finally, the radiation protection 9
branch staff has already reached out and has had 10 several meetings with the various branches at NRR and 11 NMSS to collect, to collaborate in developing a 12 targeted and agreed upon code consolidation plan.
13 My final slides show some of the near and 14 midterm planning milestones for the licensing and 15 siting dose assessment code readiness.
16 We are planning for the developing and 17 piloting of the consolidated atmospheric transport 18 engine hopefully by the end of fiscal year '21, and we 19 will continue to meet and collaborate with our co-20 developers, contractors, and counterparts in the 21 program office in developing and coordinating 22 implementation plans for the code consolidation, and 23 that concludes my presentation.
24 MEMBER REMPE: Thank you, John. Do any 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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74 members have any additional questions at this time?
1 So, not hearing any response, I'd like to ask that the 2
public line be opened and we provide the public an 3
opportunity to comment, and then we'll go around like 4
we used to when we were meeting together and ask the 5
members if they have any final thoughts before we end 6
this public session, and then my plan is to have a 7
break before we transition to the nonpublic session.
8 Does that sound good to everybody?
9 MS. WEBBER: Yes, thanks.
10 MEMBER REMPE: Okay, so let's open up the 11 public line.
12 OPERATOR: The public line is open for 13 comment.
14 MEMBER REMPE: Great, if there are any 15 members of the public who'd like to make a comment, 16 please state your name and provide that comment at 17 this time.
18 So, not hearing any comments, let's close 19 the public line, and let's go through the member list 20 and see if any of them would like to make some closing 21 comments, and we'll start with you, Charlie.
22 MEMBER BROWN: Nothing else. I asked 23 mine. Thanks, Joy.
24 MEMBER REMPE: Okay, Walt?
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75 MEMBER KIRCHNER: Nothing further at this 1
point. Thank you, Joy.
2 MEMBER REMPE: Okay, Jose?
3 MEMBER MARCH-LEUBA: Jose's trying to get 4
the mouse to work. No, I have no further comment.
5 MEMBER REMPE: Okay, thank you. Dave?
6 MEMBER PETTI: Nothing further.
7 MEMBER REMPE: Okay, Ron?
8 MEMBER BALLINGER: Only that this whole 9
process sounds like an enormous effort and 10 rebaselining all of the codes. It just seems like a 11 very, very large effort which I wonder whether the 12 schedule actually reflects what will actually happen.
13 MEMBER REMPE: Okay, thank you for your 14 comment. Matt?
15 MEMBER SUNSERI: Joy, I don't have any 16 other comments. Thanks for the presentation.
17 MEMBER REMPE: Vesna, do you have any 18 comments?
19 MEMBER DIMITRIJEVIC: No, nothing further.
20 Thanks.
21 MEMBER REMPE: Okay, so before we close 22 and take a break, I need to acknowledge I was given 23 this information and Kim was correct. The letter for 24 this will be on Volumes 4 and 5, and we have plans to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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76 work on that letter in February of next year, and so 1
in the interim, Dennis and I will work on it together 2
and I'll give him input from this meeting.
3 And so at this point, my clock says it's 4
five after the hour, so how about a --
5 MEMBER BROWN: Joy?
6 MEMBER REMPE: Yes, sir?
7 MEMBER BROWN: Before you hang us up, I 8
don't know whether I'm the only one that has the 9
problem. I just looked at my chart and I do not see 10 a closed meeting session, so if I hang up from this, 11 I don't have anything to go to your closed session.
12 MEMBER REMPE: Okay, so --
13 MEMBER BALLINGER: Same goes for me. This 14 is Ron.
15 MEMBER REMPE: It's the same place, right, 16 Derek? You help me out, because again, I wasn't 17 involved in how you were planning this with Dennis, 18 but my understanding is that we will be using the same 19 line and they'll monitor it, right, Derek?
20 MR. WIDMAYER: That's correct.
21 MEMBER REMPE: So, we're going to take --
22 and I know, Walt, you like longer first morning 23 breaks, so should I say we're going to start up at 24 9:20 or are you okay at 9:15?
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77 MS. WEBBER: Well, I think the, so the 1
staff was preparing for noon, so I'm not sure if all 2
of the staff are, you know, available to start 3
earlier. I can try to see offline if they are ready 4
to start earlier, but I'm just not sure.
5 MEMBER REMPE: Well, in light of that, we 6
can't tell members to come back in 15 minutes and then 7
tell them we don't want them, so should we just go 8
with the plan and we're going to take a very long 9
break unless I hear differently from our Chairman.
10 Matt, do you have a better suggestion?
11 MEMBER SUNSERI: No, I don't. I guess 12 we'll be finished in time for the next meeting this 13 afternoon though, right?
14 MEMBER REMPE: Tim, could you --
15 MS. WEBBER: I'm sorry. What was the 16 question? I was trying to --
17 MEMBER REMPE: If we wait until noon --
18 MS. WEBBER: Yeah.
19 MEMBER REMPE: -- D.C. time, will you give 20 us adequate time for a -- we have another meeting that 21 starts at 1:30, so this is basically going to be a 22 tighter schedule at that point. Is that --
23 MS. WEBBER: Right, so what we have 24 planned for the other session is to talk about some of 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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78 the things that I already showed you on the public 1
website, and there's a few other things that are not 2
publicly available at this point in time that we plan 3
to discuss with you.
4 So, you know, we have a lot of information 5
to present, but because we talked about some of it, I 6
think we could go fairly quickly unless you have a lot 7
of questions.
8 MR. WIDMAYER: So, hey, Kim? Hey, Kim, 9
this is Derek.
10 MS. WEBBER: Hey, Derek.
11 MR. WIDMAYER: Yeah, hey, in answering 12 emails and stuff with your staff, I'd encourage them 13 to come on early. Could you check and see --
14 MS. WEBBER: Right.
15 MR. WIDMAYER: -- if everybody is 16 available?
17 MS. WEBBER: Okay, do you want to hold on?
18 Because I see some of them. I see some of them on the 19 call, so let me Skype them individually and I'll see 20 if they're available, and then if you give me five 21 minutes or so, I'll report back to you.
22 MEMBER REMPE: So, let's take a ten-minute 23 break --
24 MS. WEBBER: Sure.
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79 MEMBER REMPE: -- and come back at --
1 well, it's 9:08 right now, so let's come back at 9:20, 2
and let's hope we're going to have a meeting, but if 3
not, we will take a longer break and deal with it.
4 Does that sound -- does everybody understand what 5
we're going to do here, members?
6 MEMBER KIRCHNER: Yeah, it's really 11:08.
7 MEMBER REMPE: Oh, I'm in Idaho, so I'm 8
looking at -- yeah, you're right. We all are having 9
trouble with that.
10 MEMBER BROWN: Let me just make sure --
11 Joy? Joy?
12 (Simultaneous speaking.)
13 MEMBER REMPE: This weekend, they were 14 saying good morning, good night, and good afternoon 15 depending on where everyone was.
16 MEMBER BROWN: Joy? Joy, Joy, Joy?
17 MEMBER REMPE: Yes, sir?
18 MEMBER BROWN: Just to make sure, we are 19 not hanging up. We're just going to come back?
20 MEMBER REMPE: Yes, you can --
21 MEMBER BROWN: Great.
22 MEMBER REMPE: You can rejoin the same 23 session at 11:20 if you're in D.C. time.
24 MEMBER BROWN: Well, I'm just going to 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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80 mute.
1 (Simultaneous speaking.)
2 MEMBER KIRCHNER: Could we give --
3 MEMBER REMPE: Pardon?
4 MEMBER KIRCHNER: Could we give the staff 5
a little more time to rally and take a break until 6
11:30?
7 PARTICIPANT: Sure.
8 MEMBER REMPE: That sounds good. And Kim, 9
whoever you can get, just go out of order and let's 10 really hope we can start at 11:30, okay?
11 MEMBER BROWN: Joy, Joy, my --
12 MEMBER REMPE: Yes, sir.
13 MEMBER BROWN: Yeah, my agenda showed on 14 Eastern Standard Time this session starting at 11:30 15 Eastern Time.
16 MEMBER REMPE: This whole thing, like I 17 have an agenda that's a final agenda, and the agenda 18 started at 9:00 D.C. time instead of at 8:30, and so 19 we've had a lot of, or instead of 9:30, so there's 20 been some time issues that are confusing, Charlie.
21 Let's just go with what we're going to be 22 doing. At 11:30 D.C. time, we're going to come back, 23 okay?
24 MEMBER BROWN: Okay, that works. Yes, 25 NEAL R. GROSS COURT REPORTERS AND TRANSCRIBERS 1323 RHODE ISLAND AVE., N.W.
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81 thank you.
1 MEMBER REMPE: Thank you very much, 2
everyone, for your patience with the changes that are 3
occurring in real time. Okay, see you at 11:30 D.C.
4 time. Thank you.
5 (Whereupon, the above-entitled matter went 6
off the record at 11:09 a.m.)
7 8
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Implementation Action Plan (IAP)
Strategy 2 Volume 4 - Licensing and Siting Dose Assessment Codes September 22, 2020 Kimberly A. Webber, Ph.D.
Division of Systems Analysis Office of Nuclear Regulatory Research
Agenda
- Staff Introduction
- Overview
- Radiation Protection Code Modernization
- Non-LWR Code Development, Volume 4, Licensing and Siting Dose Assessment Codes
- Discussion of Codes
- Discussion of Volume 4 Tasks
- Leveraging Other Non-LWR Code Readiness Work
- Other non-NRC Dose Assessment Codes for Non-LWR Readiness and Other Considerations 09/22/2020 2
- Improve mission value while enabling safe operations
- Deliver cost savings
- Develop regulatory tools
- Build staff expertise
- Leverage collaborations NRCs Be Ready Attitude 3
BlueCRAB
NRCs Integrated Action Plan (IAP) for Advanced Reactors Near-Term Implementation Action Plan Strategy 1 Knowledge, Skills, and Capacity Strategy 2 Analytical Tools Strategy 3 Flexible Review Process Strategy 4 Industry Codes and Standards Strategy 5 Technology Inclusive Issues Strategy 6 Communication ML17165A069 4
Introduction ML20030A174 Volume 1 ML20030A176 Volume 3 ML20030A178 Volume 2 ML20030A177 These Volumes outline the specific analytical tools to enable independent analysis of non-LWRs, gaps in code capabilities and data, V&V needs and code development tasks.
Strategy 2: Computer Code Readiness Code Development Plans 5
6 NRCs Integrated Action Plan (IAP) Status
Strategy 2 - Volumes 4 & 5
- Volume 4 Licensing and Siting Dose Assessment Codes (ML20028F255)
Development Plan (living document)
Volume 5 Computer Code Development Plans for Criticality, Shielding, and Accident Analysis in the Nuclear Fuel Cycle
ACRS Subcommittee meeting December 1, 2020 09/22/2020 7
Volume 4: Licensing and Siting Dose Assessment Codes 09/22/2020 8
- Landscape
- Potential for a spectrum of Non-LWR and fuel designs
- Over 10 licensing and siting dose assessment codes
- Inconsistent code development practices, by various contractors, over decades
- Overlap in code capabilities and need to use resources pragmatically
- Approach (Tasks)
- 1. Consolidate/Modernize Dose Assessment Codes
- 2. Improve characterization of Source Terms
- 3. Improve Atmospheric Transport & Dispersion Models
- 4. Update Dose Coefficient values
- 5. Develop Environmental Pathway Models
Volume 4 - Licensing and Siting Dose Assessment Codes John Tomon, CHP Chief, Radiation Protection Branch Office of Nuclear Regulatory Research
Volume 4: Licensing and Siting Dose Assessment Codes 09/22/2020 10 This report describes the licensing and siting dose assessment computer codes and how they would be applied and consolidated for the non-LWR design types.
o Section 1 Introduces the regulatory requirements.
o Section 2 Describes each code and uses.
o Section 3 Tasks related to non-LWR designs including code consolidation.
o Section 4 Discusses code readiness.
o Section 5 Conclusions.
Non-LWR Technologies 09/22/2020 11 Non-LWR Plant Description Examples Fuel Types 1 HTGR; prismatic core, thermal spectrum Framatome TRISO (rods or plates) 2 PBMR; pebble bed core, thermal spectrum X-energy, Starcore TRISO (pebbles) 3 GCFR; prismatic core, fast spectrum GA SIC clad UC (plates) 4 SFR; sodium cooled, fast spectrum PRISM, ARC, TerraPower Metallic (U-10Zr) 5 LMR; lead cooled, fast spectrum Westinghouse, Columbia Basin, Hydromine (Possibly nitride fuel.)
6 HPR; heat pipe cooled, fast spectrum Oklo, Westinghouse Metallic (U-10Zr) 7 MSR; prismatic core, thermal spectrum AHTR TRISO (plates) 8 MSPR; pebble bed, thermal spectrum Kairos TRISO (pebbles) 9 MFSR; fluoride fuel salt, thermal/epithermal spectrum Terrestrial Thorcon, FliBe Fuel salt 10 MCSR; chloride fuel salt, fast spectrum TerraPower, Elysium Fuel salt
Regulatory Needs for Dose Assessment Codes 09/22/2020 12
Image adapted from BNWL-1754, Models and Computer Codes for Evaluating Environmental Radiation Doses.
09/22/2020 13 Over 10+ codes used for NPP licensing and Siting.
Licensing and Siting Dose Assessment Codes
Safety & Environmental Review Codes 09/22/2020 14 PAVAN
(/Q)
ARCON
(/Q)
Control Room Image adapted from BNWL-1754, Models and Computer Codes for Evaluating Environmental Radiation Doses.
Safety & Environmental Review Codes 09/22/2020 15 HABIT (Chemical)
Control Room Image adapted from BNWL-1754, Models and Computer Codes for Evaluating Environmental Radiation Doses.
EXTRAN CHEM DEGADIS SLAB
Image adapted from BNWL-1754, Models and Computer Codes for Evaluating Environmental Radiation Doses.
Safety & Environmental Review Codes 09/22/2020 16 NRCDose XOQDOQ
(/Q) 80 km GALE GALE LADTAP GASPAR RADTRAN
Image adapted from BNWL-1754, Models and Computer Codes for Evaluating Environmental Radiation Doses.
Dose Consequences Code 09/22/2020 17 RASCAL Accident 129 km 129 km
Decommissioning Codes 09/22/2020 18 DandD (Decontamination and Decommissioning): compliance with the dose criteria of 10 CFR Part 20, Subpart E. Perform simple estimates of the annual dose from residual radioactivity in soils and on building surfaces.
RESRAD (Residual Radioactivity): Family of codes used to analyze human and biota radiation exposures from environmental contamination of residual radioactive materials.
Research and Other Purposes 09/22/2020 19 GENII (Generation II computer code): a set of programs for estimating radionuclide concentrations in the environment and dose to humans from acute or chronic exposures from radiological releases to the environment or initial contamination conditions.
SCALE and MELCOR are used in development of core radionuclide inventory and severe reactor accident source terms as described in Volume 3. Plan to leverage work done for Volume 3 in the licensing and siting dose assessment codes.
Dose Coefficient File Package (DCFPAK):
that includes nuclear decay data and dose and risk coefficients for exposure to radionuclides.
Volume 4: Code Readiness Tasks
- Code Consolidation & Modernization (Task 1)
- Source Term (Task 2)
- Atmospheric Transport & Dispersion (ATD) Module (Task 3)
- Dose Coefficient Module (Task 4)
- Environmental Pathways (Task 5) 20
Code Consolidation and Modernization (Task 1)
- Given the large number of Non-LWR technologies being conceived and developed, it will be resource intensive to modify each of the siting, licensing, and emergency response codes for each design type.
- Therefore, the staff is proposing to consolidate and integrate them into several codes (i.e., two or three) that are modular, flexible, efficient, and user-friendly.
09/22/2020 21
Code Consolidation Approach The three pillars to the dose assessment code consolidation process:
- Create consolidated engines
- Develop a standardized data transfer schema
- Build a single user interface 22 09/22/2020 PNNL-29717, Health Physics Codes Consolidation and Modernization
Conceptual Model for the Consolidated Code 23 09/22/2020 PNNL-29717, Health Physics Codes Consolidation and Modernization
Source Term (Task 2)
- Identify source terms inputs (i.e., radionuclide fuel inventories, reactor coolant inventories, plant design and operational data) for each of the Non-LWR designs.
- Normal (Routine) source terms
- Severe Accident source terms
- Design-Basis Accident source terms
- Transportation source terms 09/22/2020 24
Source Term (Task 2)
- Source Term Considerations:
- Source term/release rate framework database will:
- Leverage activities from Volumes 1, 2 and 3
- Estimate inventory in core/release from core
- Identify dominate release pathways
- Characterize mechanism to reduce release (e.g. filters)
- Estimate release rates,
- Use operational data where applicable 09/22/2020 25
ATD Module (Task 3)
- ATD consolidation in Phases:
- Phase 1: Consolidate ARCON, PAVAN & XOQDOQ.
- Phase 2: Evaluate the applicability of the near-field and ATD models for Non-LWR technologies.
09/22/2020 26
- These phases would leverage the experience of the meteorology staff and MACCS near-field modelling efforts from Volume 3.
09/22/2020 27 Atmospheric Engine Prototype
Dose Coefficient Module (Task 4)
- This task involves:
- Developing dosimetry modules/engines that have the flexibility to use different dose models and dose coefficient values
- Examining dose coefficient models with respect to aerosol particle size in addition to exploring the impact of tritium and carbon-14 biokinetics since these radionuclides may be in higher quantities in non-LWRs.
09/22/2020 28
Dose Coefficient Considerations
- Vision for module:
- Flexible Engines for different dose coefficient values
- Dose Coefficient Package Code (DCFPAK)
- Aerosol particle size relative to dose coefficients
- H-3 and C-14 relationship to dose coefficients
- Current State
- Some codes can choose different data sets.
- Leveraging DCFPAK datasets with US EPA.
- Possibly acquiring international dosimetry codes.
- Training RPB staff on specific designs where internal dosimetry could be significant such as MSRs.
29 09/22/2020
Environmental Pathways (Task 5) 09/22/2020 30
- Further developing the aquatic pathways (river/lake/ocean dispersion), environmental accumulation, and human/non-human biota consequence modules for codes.
- Lower priority because they are less dependent on Non-LWR designs and fuel types.
- Explore the feasibility of radionuclide particle size behavior in the environment for some non-LWR designs.
Other Considerations/Challenges
- Timing of Non-LWR submittals vs code readiness
- Consolidation vs no consolidation
- Wide range of program office participation and input
- Managing expectations 31 09/22/2020
Code Readiness
- Next Steps for Volume 4: (Near- & Mid-Term) 09/22/2020 32 Activity Date Brief SC and Full ACRS Sept 2020/Feb 2021 Build Consolidate Code Framework FY 2021 Obtain Source Terms from Most Probably Designs Ongoing Pilot of Atmospheric Models FY 2021 Include Non-LWR HP Operational Experience (Domestic and International)
FY 21 and beyond Dose and Environmental Engines FY 23 and beyond
Background Slides 09/22/2020 33
09/22/2020 34