VALmASI PROGRAM BAT AN-2DIFF DALAM PERHITUNGAN f3EFF DI TERAS FCA

VALIDASI PROGRAM BATAN-2DIFF DALAM PERHITUNGAN f3EFFDI TERAS FCA. Beberapa saran yang mendorong perbaikan program Batan-2DIFF telah meningkat daDsalah satunya adalah validasiprogram Batan-2DIFFdalam perhitungan fraksi neutron kasip efektif (f3eft)di teras FCA. f3effadalah salah satu parameter kinetik yang penting dalam analisiskese1amatanreaktor nuklir. f3effini memainkanperanan yang penting dalam interpretasi teoretik dari pengukuran reaktivitas, oleh karena itu hams diprediksi secara akurat dengan perhitungan neutronik. Validasi dilakukan dengan membandingkan hasil perhitungan f3effdi teras FCA XIX-l antara kombinasi program difusi Batan-2DIFF & ALPHA-KP daD CITATION-FBR & PERKY. Program Batan-2DIFF melakukan perhitungan fluks neutron forward daDadjoint yang akan dimanfaatkan oleh program ALPHA-KP untuk menentukan fraksi neutron kasip efektif (f3eft). Tampang lintang makroskopik efektif material di daerah teras daD di daerah blanket digenerasi dengan program perhitungan gel l-D WIMS/D4 dalam struktur 69 kelompok energi. Berbagai data neutron kasip yang diolah dari Evaluated Nuclear Data Library (ENDF/B6.2, JENDL-3.2), yang dievaluasi oleh periset Tomlinson daDyang direkomendasikan oleh WPEC/SG6, digunakan untuk melengkapi validasi ini. Perhitungan f3eff dengan kombinasi Batan-2DIFF & ALPHA-KP menyajikanhasil di bawah estimasi tetapi secara umum bersesuaian dengan CITATION-FBR & PERKY. Penggunaan evaluated library JENDL-3.2 memperlihatkan hasil yang paling dekat, yaitu -1,85 %. Perbedaan relatif sebesar 0,05% dari nilai eksperimen menunjukkanakurasiprediksi f3effdengan data nuklir WPEC/SG6 adalah yang paling baik, yang membuktikan validasi program Batan-2DIFF.
ABSTRACT
VALIDATION OF BATAN-2DIFF CODE ON THE CALCULATION OF f3EFFIN FCA CORE. Several encouraging suggestionsfor improvingthe Batan-2DIFF code have arised and one of them is validation of the Batan-2DIFF code on the calculation of effectivedelayedneutron fraction(f3eft)in FCA core. The f3eft'is one of important kinetic parameters in nuclear reactor safety analysis. This f3eff plays important role in the theoretical interpretation of reactivity measurement, therefore it has to be accurately predicted by the neutronic calculation. The validation was conducted by comparing the calculation result of f3effin FCA XIX-l core between combination of Batan-2DIFF & ALPHA-KP and CITATION-FBR & PERKY diffusion codes. The Batan-2DIFF code performs the calculation of forward and adjoint neutron fluxes which will be utilized by ALPHA-KP code to determine the effective delayed neutron fraction (f3eff). The effectivemacroscopic cross-sectionof material in core and blanket regions were generated with l-D cell calculationcode WIMS/D4 in structure of 69 energy group. Various delayed neutron data processed from Evaluated Nuclear Data Library (ENDF/B6.2, JENDL3.2), evaluated by researcher Tomlinson and recommended by WPEC/SG6 were used to complete this validation. The calculation of f3effby combination of Batan-2DIFF & ALPHA-KP presents underestimated results but generally they have agreement with those by CITATION-FBR & PERKY. The use of evaluated library of JENDL-3.2 shows the most close result, i.e. -1. 85%. The relative difference of 0.05% from
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ISSN 0854-5278 Validasi Program Bara1/-2DIFF.... Zuhair, dkk
experiment value indicates that the prediction accuracy of l3eff with nuclear data of WPEC/SG6 is the best one which proved the validation ofthe Batan-2DIFF code.