[en] The genetic algorithm (GA) has been used in reactor fuel management of core arrangement optimal calculation. The chromosome coding method has been selected, and the parameters in GA operators have been improved, so the quality and efficiency of calculation in GA program have been greatly improved. According to the result, better core fuel position arrangement can be obtained from the GA calculation

[en] It is important to monitor in core vibration with the neutron noise method. The perturbed theory (system equation and perturbed noise source), control theory (transfer function) and the reactor dynamics (point kinetic equations) have been used to build the physical model. The model has been used to interpret the power spectral density of the zero power reactor simulated experiment. In the model, a low frequency noise term has been introduced to describe the abnormal increase of low frequency part of PSD curve

[en] Application of GA in HFETR core optimization design has been discussed. A part of parameters used in program has been taken from the code used in MJTR core LP optimization program. In the same time, two new techniques, imaginary core technique and symmetric mutation operator, have been introduced. ICT has been used to reduce the calculation time of optimization, while SMO has been used to increase the engineering applicability of the core design. The optimization result shows that the conversion ratio and radioisotope output have been increased more than 10%, and the optimal LP is symmetric and practical, and satisfies the engineering requirement

[en] The neutron noise method has been used to monitoring reactor coolant boiling. Wach-Kosaly model has been used to interpret the neutron noise induced by coolant boiling. The equation based on the model is got and used for calculation. The physical variable with the relation of bubble's velocity is got from the calculated result (autopower spectral density)

[en] Genetic Algorithms are used in MJTR core loading pattern optimization programming. Encoding and crossover operators were designed relating the characteristics of the real problem. The two-dimensional hexagonal geometric multigroup diffusion code SIXTUS-2 is used in fitness calculation. For improving the quality and efficiency of the program, many math experiments have been done to find the optimal methods and parameters. Results of the optimization calculation show that all genetic algorithms optimized loading pattern are better that expert's loading pattern. The optimized schemata and optimized loading pattern of MJTR core are given

[en] Objective: To investigate the short-term effect, the adverse effects and the survival rate of brachytherapy with ¹²⁵I seed implantation for oral cancer. Methods: During the period from September 2008 to April 2012, a total of 18 patients with oral cancer were admitted to authors' hospital. All patients underwent ¹²⁵I radioactive seed implantation. Treatment planning system (TPS) was used to calculate the needed number of seeds, the space distribution and the orientation of the puncture needle. Under spiral CT guidance, ¹²⁵I seeds were implanted into the target region of tumor and in its vicinity (0.5 cm), and the particle interval was 0.5-1 cm. The particle radioactivity was 0.60-0.80 mCi (2.22 × 10⁷ - 2.96 × 10⁷ Bq). CT scanning (2 mm slice) was performed immediately after the implantation. The images were transferred to the computer of TPS for quality verification. Six cases had cervical lymph node metastases, and the same procedure of ¹²⁵I radioactive seed implantation was employed. The short-term efficacy was evaluated at two months after the treatment, and follow-up examination was conducted once every three months. The intraoperative and postoperative adverse events were recorded. Results After treatment the ulcerative lesions disappeared or shrank in different degrees and the pain gradually relieved. At six months after the treatment, the short-term efficacy of the primary lesion was as follows: CR 50.0% and PR 38.9% with an effective rate of 88.9%. For cervical lymph node metastases, CR was 70.0% and PR was 20.0%, the effective rate was 90.0%. The adverse reactions included bleeding during operation and postoperative pain. Neither radiation injury nor particle migration occurred. The patients were followed up for 9-24 months, the one - year and two-year cumulative survival rates were 94.4% and 12.2% respectively, with a median survival time of 18 months. Conclusion: For the treatment of oral cancer,brachytherapy with ¹²⁵I seed implantation is safe and effective with fewer complications. This technique is of value in clinical practice. (authors)

[en] Objective: To investigate the CT features of pulmonary sarcoidosis. Methods: Ninety patients with histologically proved pulmonary sareoidosis were retrospectively studied by using CT scans and clinical recording. Results: The main CT findings of pulmonary sarcoidosis were nodules which were seen in 69 cases (76.7%), and the nodules mostly distributed around the bronchovascular bundle (n=37, 41.1%). Other abnormalities included consolidation (n=31, 34.4%), ground-grass (n=39, 43.3%), thickening of bronchovascular bundle (n=30, 33.3%), interlobular septal lines (n=58, 64.4%), fibrosis (n=17, 18.9%) including bronchial distortion (n=8, 8.9%), linear shadow (n=5, 5.6%), and honeycombing shadow (n=4, 4.4%), air-trapping (n=3, 3.3%), bronchial straitness (n=8, 8.9%), pleural thickening (n=42, 46.7%), and hilar and mediastinal adenopathy (n=76, 84.4%). Two or more abnormal findings co-existed in 83 cases. The pulmonary lesions co-existed with hilar and mediastinal adenopathy in 76 cases. The nodules (n=25), consolidation (n=9), ground-grass (n=11), thickening of bronchovascular bundle (n=10) were improved after therapy. Ten cases of the interlobular septal (10/22), 0 of bronchial distortion (0/4), 1 case of diffuse linear (1/3), and 0 ease of honeycombing (0/2) were improved. Conclusion: CT manifestations of pulmonary sarcoidosis are varied, but has some specific radiographic features. A correct diagnosis can be made. combined with hilar and mediastinal adenopathy. (authors)

[en] The effective delayed neutron fraction is a key parameter in reactor physics calculation. In this paper, several models:prompt method, spectral exchange method, effective delayed neutron recording method, direct method and iterated fission probability method are developed to implement the parameter calculation, which is based on the continuous energy adjoint weighted Monte Carlo code. Verification is also carried out in several benchmark cores, High Flux Engineering Test Reactor and Nuclear Power Plants. As the result, it is shown that the difference between experiment and calculation of IFP method is quite well, in other methods the accuracy is different and also can be accepted. The results of six group, multi-isotopics and multi-cell calculation have also been obtained to provide the full core distribution of β_eff and overcome the difficulties in deterministic methods based on the uniformation. (author)

[en] Genetic algorithm is a stochastic optimization method which has been used in many research and engineering field in recent years. Core loading pattern of two research and test reactors, the High Flux Engineering Test Reactor and Ming Jiang Test Reactor, have been tackled using the GA optimization. Parameters have been tested and two new techniques, Imaginary Core Technique and Symmetric Mutation Operator, have been used in our GA program. As a result, conversion ratio and average cobalt output have been increased about 10% than the expert's LP. (author)

[en] The physical analyses of radioisotope production in research and test reactor were carried out. Firstly, the influence of control rod withdrawing sequence on isotope production was analyzed, and the rod withdrawing factor was obtained. Then according to the point reactor model and the reactivity-burnup linearity equation, the equations of radioisotope conversion ratio and production were acquired. Finally, several parameters including cycle length, fuel assembly (FA) numbers, initial average burnup of FAs and power in HEU and LEU core of HFETR were analyzed with these equations. It is concluded from the results that the radioisotope production increases with the control rod withdrawing sequence from the smallest to the largest value rod, and with the increase of the fuel assembly number and power, while the cycle numbers (the inspection time between adjacent cycles is unchanged) and initial average burnup have opposite effects. The results are applied in the design of reactor loading patterns. (authors)