CD-EXCALIBUR-FMS0054-RB-2_ExcaliburFusionModellingSystemSoftwareRequirementsSpecification
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.. meta::
   :description: technical note

   :keywords: ExCALIBUR,D3.1,Software,Requirements,Speciﬁcation,RB/2,Engineering,Requirements,Speciﬁcation,Abstract,This,document,provides,a,description,of,reactor,design,engineers’,requirements,for,NEPTUNE.,It,forms,part,of,the,requirements,baseline,(RB).,UKAEA,REFERENCE,AND,APPROVAL,SHEET,Client,Reference:,UKAEA,Reference:,Issue:,Date:,CD/EXCALIBUR-,FMS/0054/RB/2,1.00,November,13,,2021,Project,Name:,ExCALIBUR,Fusion,Modelling,System,Prepared,By:,Name,and,Department,Wayne,Arter,Signature,N/A,Date,November,13,,2021,BD,Reviewed,By:,Rob,Akers,November,13,,2021,Advanced,Dept.,Manager,Computing,Approved,By:,Rob,Akers,November,13,,2021,Advanced,Dept.,Manager,Computing,2,1,Introduction,This,speciﬁcation,is,based,on,four,main,sources,,namely,•,Presentation,by,Chris,Jones,(CJ),at,the,NEPTUNE,internal,workshop,on,16,December,2019,•,Points,made,in,an,email,by,Michael,Kovari,(MK),dated,19,December,2019,•,Interview,with,Zsolt,Vizvary,(ZV),on,20,December,2019,•,Use,by,author,(WA),of,SMARDDA-PFC,software,in,tokamak,reactor,design,2016-2020.,A,signiﬁcant,part,of,CJ’s,talk,concerned,calculations,of,stress,in,‘contact’,problems,and,in,tokamak-,relevant,materials,,particularly,those,to,be,used,in,and,adjacent,to,the,ﬁrst,wall.,Mention,was,also,made,of,nuclear,heating,and,activation,effects,in,the,wall,,and,their,effect,on,its,strength.,Since,NEPTUNE,is,primarily,intended,as,a,plasma,modelling,tool,,this,material,is,neglected,here,ex-,cept,insofar,as,it,has,implications,for,NEPTUNE,interfaces.,Similarly,ZV,has,as,high,priority,,a,capability,to,do,magnetic,equilibrium,calculations,so,as,to,be,able,to,calculate,electromagnetic,stresses,in,the,wall.,CJ,emphasised,that,engineering,design,at,UKAEA,makes,heavy,use,of,the,ANSYST,M,software,for,multiphysics,calculations,,and,that,since,plasma,effects,including,neutral,beams,and,fast,ions,are,not,part,of,any,standard,ﬁnite,element,toolkit,,particular,consideration,should,be,given,to,interfacing,NEPTUNE,to,ANSYS,macros,and,ACT,(Python,scripting,for,AN-,SYS).,CJ,stated,that,ANSYS,had,been,implementing,additional,physics,very,slowly,,on,a,timescale,of,decades,,and,there,is,anyway,not,a,satisfactory,licence,model,for,using,ANSYS,on,HPC,,nor,any,to,be,expected,soon.,Although,the,SMARDDA,software,takes,as,input,general,surface,triangulations,,which,may,there-,fore,represent,arbitrary,surface,topologies,,SMARDDA-PFC,calculates,power,deposition,on,the,basis,of,a,simple,,empirical,physical,model,of,transport,from,the,outer,midplane.,The,errors,in,the,model,are,frequently,unquantiﬁable,,given,an,absence,of,relevant,experimental,data,,notably,when,‘small’,limiters,are,proposed,,where,‘small’,implies,that,many,lines,of,magnetic,ﬁeld,make,several,mid-plane,passes,before,interacting,with,the,limiter(s).,The,NEPTUNE,software,should,provide,a,better,physical,model,to,enable,(1),calculation,of,the,midplane,proﬁle,of,power,‘depo-,sition’,and,associated,parameters,such,as,the,e-folding,length,λq,,when,an,exponential,is,ﬁtted,,and,(2),an,assessment,of,the,accuracy,of,the,whole,SMARDDA,surrogate,model,in,a,wide,range,of,existing,and,novel,conﬁgurations.,2,Overall,Capabilities,CJ,has,been,led,to,dream,of,a,Whole-system,full-physics,digital,twin,available,for,real,time,in-silicon,simulation,and,experimen-,tation,but,recognised,that,a,more,immediately,realisable,prospect,was,integration,of,plasma,software,into,ANSYS,WorkbenchT,M,.,3,1.,Simulations,must,be,of,known,,improved,accuracy,,so,that,the,performance,of,the,built,de-,signs,can,be,enhanced,without,sacriﬁcing,safety.,Thus,the,code,and,data,structure,should,support,mesh,convergence,studies,,and,be,‘physics,aware’,as,described,in,Section,3.,2.,The,power,load,should,be,easily,transferable,to,ANSYS,for,stress,,heat,transfer,and,other,multi-physics,analysis.,3.,The,software,should,be,easy,to,couple,to,other,physics,packages,produced,within,the,fu-,sion,community,such,as,RACLETTE,and,ERO,for,erosion,calculations,,LOCUST,and,SMARDDA-PFC,for,power,deposition,by,particles,,and,neutronics,software,such,as,MCNP.,4.,The,software,should,be,designed,to,support,easy,production,of,statistics,from,ensemble,calculations,,even,when,costs,limit,the,size,of,the,ensemble.,The,ensembles,should,be,able,to,include,different,model,selections,as,well,as,different,parameter,choices.,5.,The,software,should,be,easy,to,use,on,HPC,,eg.,through,cloud-based,services,,where,it,should,be,resilient,to,network,bottlenecks.,Its,performance,should,scale,well,and,not,depend,on,the,OS,used.,6.,The,software,should,be,able,to,exploit,GPGPUs.,7.,The,software,should,use,well-deﬁned,standard,,open,formats,for,both,input,and,output,of,data.,8.,The,code,should,be,easy,to,extend,,without,writing,new,code.,Thus,a,user,should,be,able,to,extend,(at,least,virtually),a,data,structure,to,include,a,new,parameter,,and,add,a,new,physical,effect.,9.,The,following,aspects,of,the,software,should,be,open:,(a),data,structure,speciﬁcation,and,documentation,(b),code,and,documentation,(c),test,cases,and,their,documentation,(d),all,results,and,their,documentation,4,3,Physics,Model,The,software,should,be,automatically,‘physics,aware’,,ie.,it,should,be,able,to,1.,test,the,physical,assumptions,and,orderings,used,,perhaps,by,calculations,at,randomly,placed,points,,and,when,this,is,impossible,,to,produce,output,to,enable,an,independent,person,to,check,against,a,separate,code.,2.,intelligent,enough,to,switch,to,a,simpler,assumption,when,appropriate,or,when,instructed,to,do,so,,for,example,by,using,classical,transport,coefﬁcients,when,they,apply.,3.,test,the,level,of,detail,used.,For,example,,the,code,(1),could,carry,out,an,ensemble,calcula-,tion,using,a,simpliﬁed,model,of,radiative,loss,,and,then,check,the,results,in,a,much,shorter,time,against,a,fuller,model,using,a,sampling,technique,,(2),be,able,to,identify,automatically,that,a,fully,3-D,ﬁeld,calculation,with,say,12,or,18,discrete,TF,coils,has,produced,a,toroidally,axisymmetric,ﬁeld,in,the,vacuum,vessel.,4.,simulate,transient,behaviour,,being,able,to,determine,an,initial,approximate,quasi-static,solu-,tion,,then,depending,on,the,length,of,the,simulation,relative,to,physical,timescales,of,interest,,perform,either,an,implicit,or,an,explicit,calculation.,5.,in,the,case,that,pseudo-time,is,used,,eg.,in,an,implicit,calculation,,distinguish,clearly,from,physical,time.,6.,handle,incompatible,timescales,for,bulk,and,local,behaviour,,eg.,account,for,particle,effects,on,overall,ﬂow.,5,4,Physics,Capabilities,The,software,should,be,able,to,1.,compute,the,total,power,load,on,solid,walls,,due,to,plasma,,fast,ions,and,neutral,beams,2.,compute,the,production,of,impurity,species,by,ﬁrst,wall,melt,and,evaporation.,3.,compute,heat,conduction,in,ﬁrst,wall,coatings,in,contact,with,the,plasma.,4.,perform,high,frequency,electrical,and,magnetic,analysis,,accounting,for,skin,effects,5,Geometry,1.,The,software,should,be,able,to,account,for,the,effect,of,changes,to,geometry,caused,by,radiation,swelling,,erosion,and,deposition,due,to,plasma,interaction,,and,corrosion.,2.,The,code,should,allow,periodic,toroidal,boundary,conditions.,3.,The,software,should,be,able,to,handle,0-D,,1-D,,2-D,and,3-D,representations,of,the,same,plasma,pulse,,transferring,between,the,different,representations.,4.,A,related,example,concerns,the,recognition,of,ﬁeld,axisymmetry,as,in,Section,3.,5.,Concavities,in,the,surface,,even,sharp,corners,capable,of,causing,singularities,in,the,mag-,netic,and,stress,ﬁelds,,should,be,treatable,by,the,software.,References,6

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