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"Fungsi dari batang kendali pada reaktor nuklir riset multiguna adalah membuat stabilisasi dan merupakan alat pengendali dari reaksi-reaksi berantai nuklir, dengan adanya dampak dari radiasi Cerenkov dan fluks neutron termal dalam ruang reaktor. Menggunakan Model Ising dengan pendekatan kondisi-kondisi kuantum dan percobaan melaluiperalatan Magnetic Stirrer ditentukan turunan material-material dari Sr^A^O^. Salah satu dari tiga tipe material itu adalah Sr2Al2O^8. Material ini menunjukkan kekuatan pada absorbsi fluks neutron termal sebesar 2,1 x 10s - 1,8 x 106 currie/mm, nilai Konduktivitas Elektriknya adalah 26,62 - 29,98 pada temperatur 800° - 890° C, sedangkan pada kondisi fluks neutron termal sebesar 2,1 x 105 currie/mm nilai Konduktivitas Elektriknya adalah 29,44 -37,88 pada standar IAEA. Pada nilai medan magnetik sebesar 459 tesla dan absorbsiyang dilakukan terhadap 2,1 x 105 currie/mm neutron termal, reduksi struktur kristalnya mencapai 6,88% sampai 10,95% untuk jangka waktu 25 tahun pada daya 45,7 megawatt dengan matriks elemen bahan bakar nuklir adalah UO2 yang makin diperkaya dan Pu2O serta Th2Oy.

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The functional of a multi purpose research nuclear reactor control rod blade nuclear reactor is stabilized and controlling devices for nuclear chain reactions, the existing of Cerenkov's radiation impact and thermal neutron flux in reactor chamber. Using Ising Model with quantum states approaching and testing by Magnetic Stirrer equipment had determined the Sr2 A12O2-X derivatives materials. One of three types is Sr2 A12O1.8. This material shown the strength of thermal neutron flux absorbed about 2.1 x 105 ~ 1.8 x 106 currie/mm, the value of Electrical Conductivity is 26.62 - 29.98 at 800 - 890° C temperature, however at 2.1 x l(r currie/mm thermal neutron flux condition is 29.44 - 37.88 in IAEA standard At 450 tesla magnetic field and 2.1 x JO5 currie/mm thermal neutron absorber, the crystalline structure reducted to 6.88% until 10.95% for 25 years period in 45.7 megawatts with UO2 more enrichment andPu2O also TH2Oy nuclear fuel element matrix."

"ABSTRAKTesis ini membicarakan model histeresis bahan ferroelektrik dengan meninjau teori dinding domain. Model dibuat melalui dua tahap. Pada tahap pertama membuat relasi anhisteresis Langevin dan Ising spin dengan memasukkan interaksi antar dipol. Pada tahap kedua histeresis ditinjau dengan teori dinding domain. Kurva model divalidasi dengan kurva eksperimen bahan PMN-PT-BT [ Pb(Mg,Nb)O3-PbTiO3-BaTiO3 ]. Diperoleh koefisien Pearson kurva model terhadap kurva eksperimen sebesar 0.9988. Dengan demikian kurva histeresis hasil simulasi adalah valid. Studi kurva histeresis bahan ferroelektrik PZT4 , PZT5A, PZT5H, PMNT [ Pb(Mg,Nb)TiO3 ] kristal tunggal, BZT [Ba(Zr,Ti)O3)], bahan BT-BZ (BaTiO3-BaZrO3) film tipis dan PZT [ Pb(Zr,Ti)O3 ] film tipis memperoleh harga koefisien Pearson r2 lebih besar dari 0.97 untuk model Langevin maupun Ising spin. Hal ini menunjukkan model Langevin maupun Ising spin baik digunakan untuk studi kurva histeresis berbagai bahan ferroelektrik. Bahan PZ26 (PbZrO3) kurang baik menggunakan model berbasis dinding domain, karena kurvanya tidak simetri.

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ABSTRACTThis thesis addresses the modeling of hysteresis in ferroelectric materials through consideration of domain wall theory. The model is developed in two steps. In the first step, anhysteresis relation of Langevin and Ising spin is obtained with dipol interaction. In the second step, hysteresis is incorporated through consideration of domain wall theory. Curve model is validated through curve experiment PMN-PT-BT [ Pb(Mg,Nb)O3-PbTiO3-BaTiO3 ] material. Pearson coefficient for curve model is more than 0.99. So curve model is valid. Curve hysteresis ferroelectric studies of PZT4, PZT5A, PZT5H, PMNT [ Pb(Mg,Nb)TiO3 ] single crystal, BZT [ Ba(Zr,Ti)O3)], BT-BZ (BaTiO3-BaZrO3) thin film and PZT [ Pb(Zr,Ti)O3 ] thin film materials yields Pearson coefficient more than 0.97 for Langevin and Ising spin model. It shows that Langevin or Ising spin model is good for studying hysteresis curve of ferroelectric materials. PZ26 (PbZrO3) material is not appropriate with model based on domain wall theory, because of asymetri curve."

"The functional of control rod blade nuclear reactor is stabilized device and controlling for nuclear chain reaction also the flux of thermal neutron in reactor chamber. Selecting materials based on Sr2 AI,;OV for multipurpose research reactor 50 megawatts determined by Ising Model software and programming written in Modula's language. This software consists are 4 main programmes and 38,700 sub-programmes. By simulation of Ising Model found Sr2 A1202, material. Based on Sr2 AI202_7, had been tested by Magnetic Stirrer equipment and combined with Ising Model expressed the material is Sr2 A12O1.8 . This material shown the strength of thermal neutron flux absorbed about 2.1 x 105 - 1.8 x 106 currie/mm. The values of Electrical Conductivity is 26.62 - 29.98 in 800° - 890° C temperature, however at 2.1 x 10' currielmmn thermal neutron flux condition is 29.44 -- 37.98 values in IAEA standard. At 450 testa magnetic field and 2.1 x 105 currie/mm thermal neutron absorber, the crystallization structure reduction is 6.88% until 10.95% for 25 years period in 45.7 megawatts. At present material is Zr-4 was substituted by this material, however the cost more cheaper than Zr-4. According datas, then the manufacturing design for control rod blade is investment casting and adhesive bounding with Sr2O2 substance for lining substance processes, compare with present material is casting and welding processes. The value of cubical raiser with sides 1.25 cm has the AIIV ratio as 4.8 cm' l (in standard is 4.1 cnf-') with the volume shrinkage of solidification is 3% for casting process. At joining has the radial tensile stress at the front hub fillet measuring 222 N/mm2 (in standard is 180 NImm2) and the value of tensile test is 405 MPa, meanwhile the standard around 390 MPa."