2018·217·
Fig.2(color online)NRT and BCA-arc-dpa displacement cross-section for different steels.Gray line denotes displacement
cross-section evaluated in the framework of NRT.
References
[1]M.J.Norgett,M.T.Robinson,I.M.Torrens,Nucl.Eng.and Design,33(1975)50.
[2]K.Nordlund,A.E.Sand,F.Granberg,et al.,Primary Radiation Damage in Materials.OECD,2015.[3]Kai Nordlund,Steven J.Zinkle,Andrea E.Sand,Nature Communications,9(2018)1.[4]R.E.MacFarlane,A.C.Kahler,Nuclear Data Sheets,111(2010)2739.
[5] A.Yu.Konobeyev,U.Fischer,Yu.A.Korovin,et al.,IOTA-2017:A Code for the Simulation of Ion Transport in Materials.
Technical report,Karlsruhe Institute of Technology,2017.
6-22
Evaluation of Cladding Swelling in CiADS Radiation
Environment
Korepanova Nadezda,Gu Long and Zhang Lu
The integrity of materials in reactors are associated with safety and reliability of a nuclear power plan
t.One of the most vulnerable components of a nuclear reactor is a cladding of a fuel pin,because of more aggressive environment,higher temperature and higher radiation level compare with other components.For CiADS the 15-15Ti steel has been chosen as a cladding material due to its properties.The steel was specially developed as a cladding material with increased swelling resistance.The aim of our work is to evaluate cladding swelling,because it leads to embrittlement and then,as the result,to a failure.
We have found several dependencies of swelling versus accumulated dose for steels that usually combined in one class of 15-15Ti steel [1].Here we considered swelling-dpa relations only for 15-15Ti steel (France)[2,3]and DIN 1.4970(Germany)[4],because they have the most similar compositions to each other.The level of swelling versus dose and temperature according to those relations is shown in Fig.1.
Fig.1(color online)Swelling versus dose and tempera-ture.Gray surface denote correlation for 15-15Ti [2,3],green surface denote correlation for DIN 1.4970[4].Fig.2(color online)Scheme of CiADS active core.The
hottest fuel assembly is marked by red hexagon with *sign.
·218·2018 For our work,we have chosen the swelling-dpa dependency for DIN1.4970,as it predicts higher swelling than dependency for15-15Ti and has a peak swelling temperature in the range of CiADS operating temperature.
To estimate volumetric swelling we used the damage rate and temperature presented in Table1.Here we consider only CiADS’hottest fuel pin in hottest fuel assembly.Considered fuel assembly is marked by red hexagon with *sign in Fig.2.The estimation of volumetric swelling has been made for1,5,10,20,and25years of operation on full power.The results presented in Fig.3.
双向触发二极管
Table1Damage rate and temperature for15-15Ti steel in CiADS’hottest fuel pin in hottest fuel assembly. Segment Damge rate,
dpa/EFPY
Temperature in hot毛刷制作
channel/(◦C)
70secTemperature in
铝
空气电池>发热板
average channel/(◦C)
10.988299293
2 1.429315303
3 1.915335316
4 2.385358330
5 2.696382345
7 2.274422369
8 1.790436378
9 1.324447384
100.910455389 The swelling analysis gave lifetime estimation equals23a.This evaluation is based on the fact that15-15Ti steel becomes brittle if volumetric swelling exceeds6%[1].It worth to mention,most of the fuel assembly is significantly below this limit.Only two central segments in the hot channel of the hottest assembly working in an environment favorable to reaching6%swelling limit.Therefore,it leads us to conclusion that to exploit fuel assemblies in CiADS for25a,it is necessary to introduce a shuffle scheme for assemblies.It worth to mention,that4%-swelling is the highest level of swelling attained in other assemblies after25a of operation on full power.Note that this estimation includes only the effects caused by the neutronflux.However,this gives a reasonable prediction of the expected degradation in material properties in the reactor core during its operation time.
Fig.3(color online)Time evolution of volumetric swelling of the CiADS hottest fuel assembly for hottest(panel a)and average(panel b)channels.Considered assembly marked by red hexagon with*sign in Fig.2.
References
[1]J.Seran,M.Le Flem.Steels as Core Materials for Generation IV Nuclear Reactors,page285.Number106in Woodhead Publishing
Series in Energy.Elsevier,(2016).
[2]L.Luzzi,S.Lorenzi,D.Pizzocri,et al.,Modeling and Analysis of Nuclear Fuel Pin Behavior for Innovative Lead Cooled FBR.
Technical Report RdS/PAR2013/022,ENEA,(2013).
[3]Lelio Luzzi,Antonio Cammi,Valentino Di Marcello,et al.,Nuclear Engineering and Design,277(2014)173.
[4]S.E.Lemehov,V.P.Sobolev,M.Verwerft,Journal of Nuclear Materials,416(2011)179.
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