Integration of Safety in IFMIF-DONES Design
, Miguel E. García 2, Pedro Fernández 2, Ángela Cortés 2, Gianluca D’Ovidio 1, Elena Fernández 2, Tonio Pinna 3, Maria Teresa Porfiri 3, Ulrich Fischer 4, Francisco Ogando 5, Fernando Mota 1, Yuefeng Qiu 4, Atte Helminen 6, Slawomir Potempski 7, Eduardo Gallego 8 and Ángel Ibarra 1Round 1
Reviewer 1 Report
This paper explains and discusses about the several kinds of safety of IFMIF-DONES facility; Spanish licensing frame, the implementation of the safety requirements in the design, the risk analysis and so on. It is interesting to audiences who participate in safety management of high-risk facilities.
One of the main concern on facility safety is a public impact. In this paper, the effective dose of the Most Exposed Individual at the site boundary is discussed from line 328. I think that the description about the amounts of inventory of radio-isotopes is very confusing. And an evaluation scheme of effective dose is written just a little in this paper. Authors refer Nakamura’s work, but it is better to show briefly how to calculate the exposed dose in this paper. I will explain details in the next section.
Line 106: Is the name “CODAC” a common word? It needs a reference or a simple comment. Line 117, 123, 124: The annual production of tritium is 3.9g. 0.3 g is in the main Li loop and 0.3 g is captured in the trap. The penetration from the main loop to atmospheres is order of micro-g. The sum of contributions from these three part cannot explain the annual production. The numeric value of 0.3g is the input value of the risk analysis discussed around line 330. It is better to explain clearly and exactly the balance of the tritium production and the storage. Line 141, 144: The concentrations of Ar-41 are explained “in a year” and “equilibrium value” at line 141 and 144, respectively. Considering half-life of Ar-41 (110 min), is “in a year” proper to this isotope? Line 325-327: I have already mentioned in the previous section. You referred Nakmura’s paper, but I think that the diffusion and the spread of radio-isotopes should be explained around here, or “8 hectares” and “100 m” are too unexpectedly. Line 332-333: Is skin absorption considered in the early dose? In the ref.7, the cloud-shine, inhalation, and ground-shine are taken into account. Line 361, 363: Are “subpression” and “subpressure” common words? I am very sorry not to be able to access to ISO17873. If commonly known words, please ignore this comment. Line 452: “g” seems a unit of fraction of gravity, but it needs some explication at the first time, I think.
I hope that my comments will be helpful for improvement of the paper.
Author Response
Reviewer #1
This paper explains and discusses about the several kinds of safety of IFMIF-DONES facility; Spanish licensing frame, the implementation of the safety requirements in the design, the risk analysis and so on. It is interesting to audiences who participate in safety management of high-risk facilities.
>> In fact, the risk of the facility is considered moderate to low, which of course should be demonstrated during the process of licensing
One of the main concern on facility safety is a public impact. In this paper, the effective dose of the Most Exposed Individual at the site boundary is discussed from line 328. I think that the description about the amounts of inventory of radio-isotopes is very confusing. And an evaluation scheme of effective dose is written just a little in this paper. Authors refer Nakamura’s work, but it is better to show briefly how to calculate the exposed dose in this paper. I will explain details in the next section.
>> A methodology for dose factor estimates to MEI will be part of the formal licensing process. It will be based on US-NRC Regulatory Guide methods, presently accepted under Spanish legislation. In the manuscript, reference values taken from bibliography are used, but they are just illustrative at this stage. The manuscript is updated with these explanations.
Line 106: Is the name “CODAC” a common word? It needs a reference or a simple comment.
>> CODAC stands for ‘Control, Data Access and Communications’. Added to draft.
Line 117, 123, 124: The annual production of tritium is 3.9g. 0.3 g is in the main Li loop and 0.3 g is captured in the trap. The penetration from the main loop to atmospheres is order of micro-g. The sum of contributions from these three part cannot explain the annual production.
>> A Plant Technical Specification will be that traps must be removed when loaded to 0.3 g-T maximum, i.e., approximately every month. Therefore the balance is: 0.3g in circuit + 12months*0.3g/month = 3.9g. Permeated micrograms will be trapped in ‘Vent Detritiation System’, which will serve the concerned room atmospheres.
The numeric value of 0.3g is the input value of the risk analysis discussed around line 330. It is better to explain clearly and exactly the balance of the tritium production and the storage.
>> OK, done above and in the manuscript. In line 330, note that the scenario considers mobilization only of 0.3 g-T dissolved in the lithium by means of a fire not affecting traps (placed by design in a different room or fire sector).
Line 141, 144: The concentrations of Ar-41 are explained “in a year” and “equilibrium value” at line 141 and 144, respectively. Considering half-life of Ar-41 (110 min), is “in a year” proper to this isotope?
>> OK, ‘equilibrium values’ is written in the text rather than ‘in a year’.
Line 325-327: I have already mentioned in the previous section. You referred Nakmura’s paper, but I think that the diffusion and the spread of radio-isotopes should be explained around here, or “8 hectares” and “100 m” are too unexpectedly.
>> The manuscript has been rewritten. We hope that now is better understood. Results shown in the text were intended illustrative but also meaningful, as based on available bibliography (Nakamura paper). A more formal methodology is being recently applied, based on US-NRC Regulatory Guide and accepted by Spanish Regulatory Authority (addressing full inventory, distances, weather conditions, prompt and chronic dose). These results will be presented for licensing.
Line 332-333: Is skin absorption considered in the early dose? In the ref.7, the cloud-shine, inhalation, and ground-shine are taken into account.
>> Dose conversion factor for H3 includes HTO skin absorption. Be7 does not consider skin absorption according to the original Nakamura paper.
Line 361, 363: Are “subpression” and “subpressure” common words? I am very sorry not to be able to access to ISO17873. If commonly known words, please ignore this comment.
>> Words changed to ‘depressed’ in the text (i.e., negative pressure)
Line 452: “g” seems a unit of fraction of gravity, but it needs some explication at the first time, I think.
>> Done in the text (1g = 9.8 m/s2)
I hope that my comments will be helpful for improvement of the paper.
>> Yes, thanks a lot.
Reviewer 2 Report
General comments
This manuscript describes the integration of safety in the facility and is a good example of a facility design of the safety. It is acceptable as a paper. However, the detailed important information (especially background or basic concept of designing) in each concept or design is not understood for the reviewer. Therefore, more detailed information should be described.
Detailed comments
In Sec.3, radioactivity (Bq) of radioactive materials should be shown in viewpoint of the risk estimation. In Sec.3, the estimation method of production of radioactive material and to contain in each component should be shown. In Sec.3, Dose estimation for the classification should be shown. If there is any reference, should be referred. In Sec.3, how was dose value for the classification decided? 100ｍ, 1m, 10u 3uSv/h In Sec.3, MCNPX is usually not good precision of the calculation in the region of tens of MeV.
Table and Figures
1)In Figure 1, original words of not-general abbreviations should be shown.
2) Letters in Figure 2 and 4 are too small. They cannot be read.
3) Figure 3 is a table not a figure.
4) Letters in Figure 5 are not clear.
Author Response
Reviewer #2
General comments
This manuscript describes the integration of safety in the facility and is a good example of a facility design of the safety. It is acceptable as a paper. However, the detailed important information (especially background or basic concept of designing) in each concept or design is not understood for the reviewer. Therefore, more detailed information should be described.
>> The manuscript is focused in safety aspects implemented in DONES design. The facility itself is complex and would require a long text for description, now summarized in Section 2. In any case, a more complete description is referred to other papers (as ref. [1] and [2], now included). Including more design aspects would lead to a very long paper. Explanations are added in beginning Sec. 2.
Detailed comments
In Sec.3, radioactivity (Bq) of radioactive materials should be shown in viewpoint of the risk estimation.
>> Main mass amounts of radionuclides have been also converted to Bq (see text)
In Sec.3, the estimation method of production of radioactive material and to contain in each component should be shown.
>> New text is added in the beginning of Sec. 3. There are many details to be shown concerning neutronic tools; a condensation effort has been done. State of the art methods are being applied (Monte Carlo, libraries, ‘Rigorous two steps’ methodology, etc.)
In Sec.3, Dose estimation for the classification should be shown. If there is any reference, should be referred.
>> The classification of rooms in terms of dose rates is the desired one taking into account expected main operations during beam-on and maintenance periods. The classification is then systematically verified to show compliance (MCNPX calculations, refinement of models, ongoing iterative activities). Usage of ad-hoc Remote Handling devices is expected in areas with high dose rate values. Explanations added at the end of Sec. 3.
In Sec.3, how was dose value for the classification decided? 100ｍ, 1m, 10u 3uSv/h
>> The basis is Spanish ‘Safety Instruction GS-07.06’ and European Directive. Text in Figure 2 is updated.
In Sec.3, MCNPX is usually not good precision of the calculation in the region of tens of MeV.
>> Libraries applied in DONES design are state of the art ones. The Fusion Evaluated Nuclear Data Library (FENDL) with the current version 3.1d, is the reference data library for IFMIF-DONES. Concerning deuteron transport, specific developments were done, as MCUNED or McDeLicious. The manuscript includes now this information in Section 3.
Table and Figures
1)In Figure 1, original words of not-general abbreviations should be shown.
>> Text in the figure is updated
2) Letters in Figure 2 and 4 are too small. They cannot be read.
>> Figures are updated
3) Figure 3 is a table not a figure.
>> OK. Corrected
4) Letters in Figure 5 are not clear.
>> OK. Corrected
Reviewer 3 Report
This paper overviews the safety design of IFMIF-DONES. Since the contents are of interest for readers of the journal, the reviewer would like to recommend to publish this article in the journal after minor revisions.
Page 2, lines 84-85
As far as the reviewer knows, produced neutron energy is not above 40 MeV but around 14 MeV.
Page 4, lines 141-144
Since the half-life of Ar-41 is just 2 hours, annual amount of production 1E7 Bq is not meaningful. An equilibrium amount just like the line 144 is better.
Page 5, Fig.2
Characters in the figure are not clear.
Page 5, line 192
Please explain what is “RINR”.
Page 9, line 323
Is it possible to explain the reason for selecting the 10 %?
Page 9, the last paragraph
Dose conversion factors for tritium and Be-7 are given but not for the ACP.
Page 12, Figure 5
This is not a figure but a table.
Author Response
Reviewer #3
This paper overviews the safety design of IFMIF-DONES. Since the contents are of interest for readers of the journal, the reviewer would like to recommend to publish this article in the journal after minor revisions.
Page 2, lines 84-85
As far as the reviewer knows, produced neutron energy is not above 40 MeV but around 14 MeV.
>> Neutron spectrum in DONES goes up to 40 MeV (slightly higher in fact) as a result of the impacting 40 MeV deuterons with lithium. This is different than in a first wall fusion machine, which shows an spectrum with a peak around 14 MeV. However, the effects on materials of DONES spectrum and flux will be very similar to that expected in fusion in terms of dpa and He/H production.
Page 4, lines 141-144
Since the half-life of Ar-41 is just 2 hours, annual amount of production 1E7 Bq is not meaningful. An equilibrium amount just like the line 144 is better.
>> 1E7 Bq of Ar-41 is the equilibrium value in the room (assuming no ventilation), not annual production. Sorry for the wording. The manuscript has been corrected.
Page 5, Fig.2
Characters in the figure are not clear.
>> The figure has been improved and enlarged
Page 5, line 192
Please explain what is “RINR”.
>> Done. Manuscript improved.
Page 9, line 323
Is it possible to explain the reason for selecting the 10 %?
>> Not really, we admit. It is an arbitrary but conservative value for illustrative purposes at this stage, open to discussion. An additional reference is that lithium species aerosol production is expected in the range of some 10-20% in case of lithium fire. In any case, the contribution to the total dose by ACP is very small. The manuscript is updated with no further reference to the 10% percentage.
Page 9, the last paragraph
Dose conversion factors for tritium and Be-7 are given but not for the ACP.
>> Right. They are available (Mn-56, Cr-51…) but ACP estimates still are pending of refinement as a result of cold trap operation. There is also some uncertainty concerning original impurities in the supplied lithium. In any case, the present global ACP estimate is small (4E11 Bq), no trap operation considered, and contribution to dose is also expected small. The definitive contribution will be provided in licensing process. The manuscript is modified in the sense that ACP contribution to the dose is not provided in the illustrative scenario, while expected low.
Page 12, Figure 5
This is not a figure but a table.
>> OK. Manuscript changed.
Round 2
Reviewer 1 Report
Almost all comments are cleared up but I want to confirm 3 points and request to correct a simple mistake.
Line 186: In your new manuscript, ‘in a year’ just changed ‘equilibrium value’ without change of its value. If “some 1E7 Bq” is correct as an equilibrium value, no problem.
Figure 2: It looks that the old figure is on the top of the new figure. Will it be removed from the final version?
Line 377-393: Is a group of line 377-384 a part of the caption of figure. 3? It was hard for me to understand a relation between figures and captions.
Line 526: “Figure 5” may be “Table 4”. Please check other citation points.
I hope these comments will be helpful.
Author Response
Reviewer #1
Almost all comments are cleared up but I want to confirm 3 points and request to correct a simple mistake.
Line 186: In your new manuscript, ‘in a year’ just changed ‘equilibrium value’ without change of its value. If “some 1E7 Bq” is correct as an equilibrium value, no problem.
>> It is ‘some 1E7 Bq, equilibrium value’, as now written in draft 2.
Figure 2: It looks that the old figure is on the top of the new figure. Will it be removed from the final version?
>> Old ‘Fig.2’ should be removed, yes. It seems in fact that ‘old Fig.2’ still appear (although not in my printed version). I deleted again with ‘word/ control of change’ again.
Line 377-393: Is a group of line 377-384 a part of the caption of figure. 3? It was hard for me to understand a relation between figures and captions.
>> Lines 364 to 371 (according to the last version of the downloaded manuscript) are captions of Fig.3 (9 points size). Captions explain many acronyms used in the figure.
Line 526: “Figure 5” may be “Table 4”. Please check other citation points.
>> OK. Changed. (Two more citations changed)
I hope these comments will be helpful.
>> Yes, thank you.
Reviewer 2 Report
This manuscript is good as the paper and is well revised according to the reviewer's comments. Therefore, the reviewer agree to accept the manuscript as the paper.
Reviewer 3 Report
The paper has been modified according to th reviewer’s comments. The reviewer thinks this paper is ready for publication in the present form.
Author Response
Reviewer #3
The paper has been modified according to th reviewer’s comments. The reviewer thinks this paper is ready for publication in the present form.
>> OK. Thanks for the useful review.
Round 3
Reviewer 1 Report
This manuscript has been revised well according to the reviewer's comments.
I think that this manuscript will be acceptable in present form.
