• Nuclear Engineering and Technology
• /
• v.51 no.2
• /
• pp.356-368
• /
• 2019

This paper presents the verification and validation (V&V) of the STREAM/RAST-K 2.0 code system for a pressurized water reactor (PWR) analysis. A lattice physics code STREAM and a nodal diffusion code RAST-K 2.0 have been developed by a computational reactor physics and experiment laboratory (CORE) of Ulsan National Institute of Science and Technology (UNIST) for an accurate two-step PWR analysis. The calculation modules of each code were already verified against various benchmark problems, whereas this paper focuses on the V&V of linked code system. Three PWR type reactor cores, OPR-1000, three-loop Westinghouse reactor core, and APR-1400, are selected as V&V target plants. This code system, for verification, is compared against the conventional code systems used for the calculations in nuclear design reports (NDRs) and validated against measured plant data. Compared parameters are as follows: critical boron concentration (CBC), axial shape index (ASI), assembly-wise power distribution, burnup distribution and peaking factors. STREAM/RAST-K 2.0 shows the RMS error of critical boron concentration within 20 ppm, and the RMS error of assembly power within 1.34% for all the cycles of all reactors.

• Nuclear Engineering and Technology
• /
• v.56 no.5
• /
• pp.1562-1573
• /
• 2024

This study rigorously examined uncertainty in the TMI-1 benchmark within the Uncertainty Analysis in Modeling (UAM) benchmark suite using the STREAM/RAST-K two-step method. It presents two pivotal advancements in computational techniques: (1) Development of an uncertainty quantification (UQ) module and a specialized library for the pin-based pointwise energy slowing-down method (PSM), and (2) Application of Principal Component Analysis (PCA) for UQ. To evaluate the new computational framework, we conducted verification tests using SCALE 6.2.2. Results demonstrated that STREAM's performance closely matched SCALE 6.2.2, with a negligible uncertainty discrepancy of ±0.0078% in TMI-1 pin cell calculations. To assess the reliability of the PSM covariance library, we performed verification tests, comparing calculations with Calvik's two-term rational approximation (EQ 2-term) covariance library. These calculations included both pin-based and fuel assembly (FA-wise) computations, encompassing hot zero-power and hot full-power operational conditions. The uncertainties calculated using both the EQ 2-term and PSM resonance treatments were consistent, showing a deviation within ±0.054%. Additionally, the data compression process yielded compression ratios of 88.210% and 92.926% for on-the-fly and data-saving approaches, respectively, in TMI fuel assembly calculations. In summary, this study provides a comprehensive explanation of the PCA process used for UQ calculations and offers valuable insights into the robustness and reliability of newly developed computational methods, supported by rigorous verification tests.

• Nuclear Engineering and Technology
• /
• v.53 no.9
• /
• pp.2788-2802
• /
• 2021

Multigroup cross section (MG XS) generation by the UNIST in-house Monte Carlo (MC) code MCS for fast reactor analysis using nodal diffusion codes is reported. The feasibility of the approach is quantified for two sodium fast reactors (SFRs) specified in the OECD/NEA SFR benchmark: a 1000 MW_th metal-fueled SFR (MET-1000) and a 3600 MW_th oxide-fueled SFR (MOX-3600). The accuracy of a few-group XSs generated by MCS is verified using another MC code, Serpent 2. The neutronic steady-state whole-core problem is analyzed using MCS/RAST-K with a 24-group XS set. Various core parameters of interest (core k_eff, power profiles, and reactivity feedback coefficients) are obtained using both MCS/RAST-K and MCS. A code-to-code comparison indicates excellent agreement between the nodal diffusion solution and stochastic solution; the error in the core k_eff is less than 110 pcm, the root-mean-square error of the power profiles is within 1.0%, and the error of the reactivity feedback coefficients is within three standard deviations. Furthermore, using the super-homogenization-corrected XSs improves the prediction accuracy of the control rod worth and power profiles with all rods in. Therefore, the results demonstrate that employing the MCS MG XSs for the nodal diffusion code is feasible for high-fidelity analyses of fast reactors.

• Tuberculosis and Respiratory Diseases
• /
• v.47 no.6
• /
• pp.817-823
• /
• 1999

Background: The prevalence of allergic disease has increased substantially over the past decades. The reasons for these trends are complex but include increased environmental allergen exposure. Environmental control measures are of particular importance in the prevention and management of allergic disease. Thus, we purposed to evaluate the changes of causative allergens in allergic patients in Chonbuk provincial area that began industralized recently. Method: To evaluate the allergens epidemiologically, we performed skin prick tests and RAST in 201 allergic patients from February, 1984 to February, 1985 and 339 patients from February, 1997 to February, 1998. Results: The Following results were obtained. 1) Total sensitization rates did not change significantly(74.2% vs 75.8%, p=0.664). 2) Positive reaction rates to pollens were similar(35.8% vs 30.1%, p=0.17). 3) Positive rates to HDM(house dust mite) were decreased(66.1% vs 56.3%, p=0.02). 4) Positive rates to fungi and animal danders were decreased significantly(p<0.001). Conclusion : Environmental allergens associated with hygine in Chonbuk provincial areas such as HDM and fungi are decreased significantly during 13 years.

• Parasites, Hosts and Diseases
• /
• v.21 no.1
• /
• pp.27-31
• /
• 1983

21명의 간흡충 감염환자 및 15명의 건강인으로부터 혈청을 수집하여 혈청내 IgE와 간흡충에 대한 특이 IgE 항체를 RIST와 RAST법을 이용하여 측정하였다. 간흡충 감염환자 및 건강인의 혈청 IgE와 특이 IgE는 각각 2,372 lU/ml과 364IU/ml 그리고 52.0%와 4.4%로 간흡충 감염자에서 모두 유의하게 상승되어 있었으며 (p<0.001 및 p<0.01), 혈청 IgE의 상승과 특이 IgE의 상승은 상호 밀접한 관계가 있었고(r=0.9451), 혈청 IgE와 EPG(r=0.6056), 특이 IgE와 EPG(r=0.5693) 역시 상관 관계가 있었다. 이상의 결과로 보아 간흡충 감염은 인체 혈청내 IgE 및 특이 IgE항체를 상승시키며, IgE 및 간흡충에 대한 특이 IgK는 숙주-기생충간의 면역반응에 관여할 것으로 생각된다.

• Journal of Yeungnam Medical Science
• /
• v.9 no.2
• /
• pp.239-247
• /
• 1992

A clinical analysis was done on 134 cases with bronchial asthma who were admitted to the Department of Pediatrics Yeungnam University from May 1987 to October 1991. The results were as followings; 1) The peak age of bronchial asthma was under 2 years. The sex ratio of male to female was 2.9 : 1. 2) The out-break of bronchial asthma was most common in fall, especially in September. 3) The past history of other allergic diseases were present in 22.4% of patients(30/134 cases), and the previous bronchiolitis in infancy were experienced in 12.7% of patients(17/134 cases). 4) According to the skin test for allergens done by RAST, the most common allergens were Mites and House dust. 5) Eosinophilia(T.E.C>250/min) was found in 29.1% of patients, and elevated IgE level(>200 $IU/m{\ell}$) was found in 63.2% of patients. 6) No significant differences in the serum IgE level were found between male and female patients. No significant differences in the serum IgE level were found between asthma patients with and without other allergic diseases. 7) The serum IgE level of school aged patients was significant higher than that of preschool aged(p<0.01).

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.4 no.1
• /
• pp.47-53
• /
• 2001

Purpose: Following up the cases of cow's milk-sensitive enteropathy (CMSE), We observed the development of clinical tolerance with cow's milk and other foods. We investigated the clinical outcome of CMSE. Methods: We reviewed the clinical records of patients who had been admitted and diagnosed as CMSE by responses to cow's milk challenge and elimination test and the findings of small intestinal biopsy at Department of Pediatrics, Taegu Catholic University Hospital from March 1992 to March 1997. All of them were being fed with protein hydrolysate before 6 months old, and tried cow's milk and other foods challenge test at following each two month. Twenty-one cases of them returned to be followed. The age at admission was $30.7{\pm}8.8$ (18~47) days old and at survey was $43.4{\pm}23.7$ (16~84) months old. Results: 1) Although the body weight at birth of the patients was 25~75 percentile, all on admission was below 3 percentile. The body weight on interview was 25~75 percentile. 2) The development of clinical tolerance in cow's milk was observed at 16~24 months of age and the tolerance rate was 61% at 12 months of age, 90% at 16 months of age. The development of clinical tolerance in other foods was observed at 10~24 months of age and the tolerance rate was 33% at 12 months of age, 80% at 18 months of age. 3) Adverse reactions after challenge test with cow's milk were observed at 19 cases, manifestated as vomiting (31%), diarrhea (31%), irritability or lethargy (21%), skin rash (10%), and abdominal distention (5%). 4) Comparing serum IgE and milk RAST positive group on admission (5 cases) and negative group on admission (16 cases), there was no significant difference at the age of tolerance in cow's milk (p>0.05), the age of tolerance in other foods (p>0.05), allergy history in family, and the incidence of other allergic diseases. 5) The history of family allergy was observed in 3 cases (14%) in 21 patients and 3 cases (14%) showed rhinitis, urticaria or asthma through a follow-up interview. Conclusion: The development of clinical tolerance in cow's and other foods was sharply increased at 12 months of age and most of all tolerated within 24 months of age. CMSE is a temporary disorder of infancy.

• Asian-Australasian Journal of Animal Sciences
• /
• v.12 no.8
• /
• pp.1251-1257
• /
• 1999

Two experiments were conducted to determine the effects of roasting and extrusion on nutritional value of conventional and low-inhibitor soy beans for nurser-age pigs. In Exp. 1, 100 weaning pigs (7.5 kg average initial BW) were used in a 35-d growth assay to determine the effects of processing method (roasting in a Rast-A-Tron$^{TM}$ raster vs extrusion in an Insta-Pro$^{TM}$ extruder) on the nutritional value of Williams 82 soybeans with (+K) and without (-K) gene expression for the Kunitz trypsin inhibitor. Treatments were 48% soybean meal with added soybean oil, +K roasted, +K extruded, -K roasted and -K extruded. All diets were formulated to contain 3.5 Mcal DE/kg, with 0.92% lysine for d 0 to 14 and 0.76% lysine for d 14 to 35 of the experiment. The lysine concentrations were 80% of NRC (1988) recommendations to accentuate difference in response to protein quality and lysine availability. For d 0 to 14, pigs fed extruded soybeans (+K and -K) had greater ADG (p<0.001), ADFI (p<0.09) and gain/feed (p<0.01) than pigs fed roasted soybeans. For d 14 to 35 and overall, the same effects were noted, i.e., pigs fed extruded soybeans had greater ADG, ADFI and gain/feed than pigs fed roasted soybeans (p<0.03). Also, pigs fed -K soybeans were more efficient (p<0.008) than pigs fed +K soybeans. In Exp. 2, 150 weanling pigs (7.0 kg average initial BW) were used in a 35-d growth assay. All diets were formulated to contain 3.5 Mcal DE/kg, with 1.25% lysine for d 0 to 14 and 1.10% lysine for d 14 to 35 of the experiment. The lysine concentrations were formulated to be in excess of NRC recommendation to determine if differences in nutritional value of the soybean preparations could be detected in protein-adequate diets. For d 0 to 14 (p<0.06), 14 to 35 (p<0.03) and 0 to 35 (p<0.02), pigs fed extruded soybeans had greater ADG and gain/feed than pigs fed roasted soybeans. Apparent digestibilities of DM, N and GE were greater for diets with extruded soybeans than diets with roasted soybeans and diets with soybean meal and soybean oil were intermediate. The response to extrusion processing was greater with -K than +K soybeans, with pigs fed extruded -K soybeans having the greatest growth performance and nutrient digestibilities and lowest skin-fold thickness of any treatment. In conclusion, extrusion yielded a full-fat soy product of greater nutritional value than roasting. Also, selection against genetic expression of the Kunitz trypsin inhibitor improved nutritional value of the resulting soybean preparations.

• Tuberculosis and Respiratory Diseases
• /
• v.39 no.2
• /
• pp.159-166
• /
• 1992

Background:Sulfiting agents are widely used as preservatives and antioxidants in foods, beverages and drugs including bronchodilators. There have been reports of sulfite-related reactions such as anaphylaxis, urticaria, angioedema, abdominal discomfortness as well as bronchospasm. Several investigators reported that sulfite-sensitive asthmatic patients comprised from 3.9% to 8.2% of all asthmatic patients and its prevalence was higher in steroid-dependent group than in steroid-independent group. Subjects and Method:We performed oral provocation test with sodium bisulfite and aspirin in 17 asthmatic patients who have experienced aggravation of their symptoms after administration of drugs or foods. All of them were steroid dependent asthmatics. We observed clinical symptoms and steroid requirements from 1 to 18 months. Result:Ten of them showed severe bronchoconstriction after the ingestion of sodium bisulfite (50 to 200 mg) within 30 minutes. Concurrent aspirin intolerance was noted by oral provocation test in four cases (40%). Three of them showed positive responses on skin prick test with sulfite (10 or 100 mg/ml). Mean total eosinophil counts was $844/mm^3$ at asthmatic attack. And there was no significant responses on skin prick test and IgE-RAST to common inhalant allergens. After complete avoidance from sulfite containing foods and drugs as well as antiasthmatic medication for 1 to 18 months, nine of them (90%) could stop or reduce the steroid requirements. ConcIusion:It was suggested that severe steroid dependent and intrinsic type of asthmatic patients should be evaluated for sulfite-sensitivity.

• Pediatric Gastroenterology, Hepatology & Nutrition
• /
• v.3 no.1
• /
• pp.30-40
• /
• 2000

Purpose: During the first year of life, cow's milk protein is the major offender causing food allergy. Cow's milk allergy (CMA) affects 2~7% of infants, of which approximately one-half show predominantly gastrointestinal symptoms. We studied the clinical types of cow's milk allergy with predominantly gastrointestinal symptoms (CMA-GI) of childhood. Methods: The retrospective study was performed on 30 (male 22, female 8) patients who had diagnosed as CMA-GI during 2 years and 3 months from March 1995 to June 1997. Results: 1) Children with CMA-GI presented in the three types of clinical manifestation on the basis of time to reaction to milk ingestion: Quick (Q) onset (5 cases), Slow (S) onset (20 cases), Quick & Slow (Q&S) (5 cases). 2) Age on admission of the three groups was significantly different (p<0.05): (Q onset: $81.4{\pm}67.1$ days, S onset: $31.9{\pm}12.7$ days, Q&S: $366.0{\pm}65.0$ days). Although the body weight at birth was 10~95 percentile in all patients, body weight on admission was different: (Q onset: 10~50 percentile, S onset: below 10 percentile, Q&S: 10~25 percentile). S onset group was significantly different compared with other groups (p<0.05) and 90% of this one was failure to thrive below 3 percentile. 3) Peripheral leukocyte counts were as followings: (Q onset: $5,700{\sim}12,300/mm^3$, S onset: $10,000{\sim}33,400/mm^3$, Q&S: $5,200{\sim}14,900/mm^3$). Slow onset group was significantly different compared with other groups (p<0.05). Serum albumin levels on admission were as followings: (Q onset: $4.2{\pm}0.4\;g/dl$, S onset: $3.0{\pm}0.3\;g/dl$, Q&S: $4.0{\pm}0.3\;g/dl$). S onset group was significantly different compared with other groups (p<0.05) and 85% of this one was below 3.5 g/dl. 4) Although morphometrical analysis on small intestinal mucosa did not show enteropathy in Q onset and Q&S groups, all cases of S onset revealed enteropathy: 45% of this one showed subtotal villous atrophy, 55 % showed partial villous atrophy. 5) Allergic reaction test to other foods was not performed in S onset group because of ethical problem and high risk in general condition. In Q onset group, allergic reaction to one or two other foods: soy formula, weaning formula and eggs. Q&S goup revealed allergic reactions to several foods or to most of all foods except protein hydrolysate formula: eggs, potatos, some kinds of sea food, apples, carrots, beef and chicken. 6) Serum IgE level, peripheral eosinophil counts, milk RAST, soy RAST, skin test were not significantly different among groups. Conclusion: CMA-GI may present in three clinical ways on the basis of time to reaction to milk ingestion, typical clinical findings and morphologic changes in the small bowel mucosal biopsy specimens. This clinical subdivision might be helpful in diagnostic and therapeutic approaches in CMA-GI. Early suspicion is mandatory especially in S onset type because of high risks with malnutrition and enteropathy.