Embedded fission source approach to analyze external source effect in a subcritical reactor

Zafar, Zafar Iqbal,Kim, Myung Hyun Elsevier 2018 Nuclear engineering and design Vol.327 No.-

<P><B>Abstract</B></P> <P>A simple modification of the fission source spectrum is proposed for the Monte Carlo calculation for externally driven subcritical reactors. Embedded fission source (EFS) approach replaces the fission spectrum with the collective spectrum of the external source and fission working in a small region near to external source only. This model provides eigenvalue search with external source contribution resulting in direct connection with isotope depletion calculation within Monte Carlo simulation. MCNPX 2.6.0 is modified for EFS and tested for three kinds of reactor problems; critical fast reactor driven subcritical reactor, accelerator driven subcritical reactor and fusion-fission hybrid reactor. The effectiveness of the external sources is determined by the extra amount of the TRU isotopes burnt and increase in the core multiplication level. The tests were performed for two subcritical cases; <I>k<SUB>eff</SUB> </I> ∼ 0.986 and <I>k<SUB>eff</SUB> </I> ∼ 0.959, with initial TRU loading of 188.8 kg and 183.2 kg, respectively. The EFS approach is validated by simulating a fission source driven system which gave the multiplication factor comparable to the original MCNPX within one standard deviation (32 pcm). The difference in TRU burn-up for both subcritical cases is of the order of 0.1% for each driving neutron source option. The study showed that the EFS can be a simple and a reliable approximation for the external source analysis.</P> <P><B>Highlights</B></P> <P> <UL> <LI> An approximate technique, Embedded Fission Source model to account for the external source effect in a subcritical system. </LI> <LI> Philosophy and Mathematical basis of the EFS are explained. </LI> <LI> An algorithm to incorporate EFS into the MCNPX is introduced. </LI> <LI> Change in the multiplication factor caused by the external source is presented. </LI> <LI> The benefit of using harder neutron spectrum in transmutation of TRU isotopes is ascertained. </LI> </UL> </P>

Evaluation of the reutilization of used nuclear fuel in a PWR core without reprocessing

Zafar Iqbal Zafar,박윤서,김명현 한국원자력학회 2019 Nuclear Engineering and Technology Vol.51 No.2

Use of the reconstructed fuel assemblies from partially burnt nuclear fuel pins is analyzed. This reutilizationoption is a potential candidate technique to make better use of the nuclear resources. Standardtwo step method is used to calculate node i.e. fuel assembly average burnup and then pin by pin h valuesare reconstructed to ascertain the residual reactivity in the used fuel pins. Fuel pins with h >1:0 are usedto reconstruct to-be-reused fuel assemblies. These reconstructed fuel assemblies are burnt during thecycle 3, 4, 5 and 6 of a 1000MWPWR core by replacing fresh, once burnt and twice burnt fuel assembliesof the reference core configurations. It is concluded that using reconstructed fuel assemblies for the freshfuel affect dearly on the cycle length (>50 EFPD) when more than 16 fresh fuel assemblies are replaced. However, this loss is less than 20 days if the number of fresh fuel assemblies is less than eight. For thecase of replacing twice burned fuel, cycle length could be increased slightly (10 days or so) providedburnt fuel pins from other reactors were also available. Reactor safety parameters, like axial off setð<±10%Þ, Doppler temperature coefficient ð <0Þ, moderator temperature coefficient at HFP ð <0Þ arealways satisfied. Though, 2D and 3D pin peaking factors are satisfied ð <1:55Þ and ð <2:52Þ respectively,for the cases using eight or less reconstructed fuel assemblies only

Assessment of the dose rate from neutrons and gamma for spent fuel storage pool loaded with ATF spent nuclear fuels

Zafar Iqbal Zafar,Duy Long Ta,Jin Ho Jeong,Ser Gi Hong 대한방사선방어학회 2022 대한방사선방어학회 학술발표회 논문요약집 Vol.2022 No.11

A Realistic Channel Model for OFDM Based Underwater Acoustic Communications

Zafar Iqbal,Hyeong-Won Jeon(전형원),Heung-No Lee(이흥노) 한국통신학회 2012 한국통신학회 학술대회논문집 Vol.2012 No.6

Phytotoxic effects of mercury on seed germination and seedling growth of Albizia lebbeck (L.) Benth. (Leguminosae)

Iqbal, Muhammad Zafar,Shafiq, Muhammad,Athar, Mohammad Techno-Press 2014 Advances in environmental research Vol.3 No.3

A study was conducted to determine the phytotoxic effect of mercury on seed germination and seedling growth of an important arid legume tree Albizia lebbeck. The seeds germination and seedling growth performance of A. lebbeck responded differently to mercuric chloride treatment (1 mM, 3 mM, 5 mM and 7 mM) as compared to control. Seed germination of A. lebbeck was significantly (p < 0.05) affected by mercury treatment at 1 mM. Root growth of A. lebbeck was not significantly affected by mercury treatment at 1 mM, and 3 mM. Shoot and root length of A. lebbeck were significantly (p < 0.05) affected by 5 mM concentration of mercury treatment. Increase in concentration of mercury treatment at 5 mM and 7 mM significantly (p < 0.05) reduced seedling dry weight of A. lebbeck. The treatment of mercury at 1 mM decreased high percentage of seed germination (22%), seedling length (10%), root length (21.85%) and seedling dry weight (9%). Highest decrease in seed germination (51%), seedling (34%), root length (48%) and seedling dry weight (41%) of A. lebbeck occurred at 7 mM mercury treatment. A. lebbeck showed high percentage of tolerance (78.14%) to mercury at 1 mM. However, 7 mM concentration of mercury produced lowest percentage of tolerance (51.65%) in A. lebbeck. The seed germination potential and seedling vigor index (SVI) clearly decreased with the higher level of mercury. Plantation of A. lebbeck in mercury-polluted area will help in reducing the burden of mercury pollution. A. lebbeck can serve better in coordinating in land management programs in metal contaminated areas. The identification of the toxic concentration of metals and tolerance indices of A. lebbeck would also be helpful for the establishment of air quality standard.

Allelopathic effects of red pepper (Capsicum annuum L.) and coriander (Coriandrum sativum L.) on early seedling growth of wheat (Triticum aestivum L.)

Iqbal, Muhammad Zafar,Ahmed, Lubna,Shafiq, Muhammad,Athar, Mohammad Techno-Press 2015 Advances in environmental research Vol.4 No.1

A pot experiment was conducted to assess the effects of red pepper (Capsicum annuum) and coriander (Coriandrum sativum) on seedling growth of wheat (Triticum aestivum). The aqueous extracts treatment of red pepper and coriander showed a significant (p < 0.05) reduction in root, shoot and seedling length, number of leaves and seedling dry weight of wheat (T. aestivum) as compared to control. The inhibitory different effect on growth of wheat (T. aestivum) was directly proportional to the increasing concentration (1, 2, 3, 4 and 5%) of aqueous extracts of red pepper and coriander as compared to control treatment (0%). The root, shoot, seedling length and number of leaves of T. aestivum significantly p < 0.05 decreased at 5% concentration of red pepper as compared to control. The root, shoot and seedling growth of T. aestivum was also significantly reduced at 1, 2, 3, 4 and 5% concentration of coriander as compared to control. The root, shoot and leaves dry weight of T. aestivum at 5% coriander extract treatment concentration decreased as compared to control. The tolerance in seedlings of T. aestivum to red pepper and coriander extract treatment was dose dependent as compared to control. The seedlings of T. aestivum showed low percentage of tolerance to pepper extract treatment than coriander extract treatment.

Molecular Genetic Studies on 167 Pediatric ALL Patients from Different Areas of Pakistan Confirm a Low Frequency of the Favorable Prognosis Fusion Oncogene TEL-AML1 (t 12; 21) in Underdeveloped Countries of the Region

Iqbal, Zafar Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.8

TEL-AML1 fusion oncogene (t 12; 21) is the most common chromosomal abnormality in childhood acute lymphoblastic leukemia (ALL). This translocation is associated with a good prognosis and rarely shows chemotherapeutic resistance to 3-drug based remission induction phase of treatment as well as overall treatment. Thus, the higher the frequency of this fusion oncogene, the easier to manage childhood ALL in a given region with less intensive chemotherapy. Although global frequency of TEL-AML1 has been reported to be 20-30%, a very low frequency has been found in some geographical regions, including one study from Lahore, Punjab, Pakistan and others from India. The objective of present study was to investigate if this low frequency of TEL-AML1 in pediatric ALL is only in Lahore region or similar situation exists at other representative oncology centers of Pakistan. A total of 167 pediatric ALL patients were recruited from major pediatric oncology centers situated in Lahore, Faisalabad, Peshawar and Islamabad. Patients were tested for TEL-AML1 using nested reverse transcription polymerase chain reaction (RT-PCR). Only 17 out of 167 (10.2%) patients were found to be TEL-AML1 positive. TEL-AML1+ALL patients had favorable prognosis, most of them (82.4%, 14/17) showing early remission and good overall survival. Thus, our findings indicate an overall low frequency of TEL-AML1 in Pakistan pediatric ALL patients, in accordance with lower representation of this prognostically important genetic abnormality in other less developed countries, specifically in south Asia, thus associating it with poor living standards in these ethnic groups. It also indicates ethnic and geographical differences in the distribution of this prognostically important genetic abnormality among childhood ALL patients, which may have a significant bearing on ALL management strategies in different parts of the world.

Theoretical Overturning Analysis of a 2.6-kW Two-Row Walking-Type Automatic Pepper Transplanter

IQBAL MD ZAFAR,Islam Md Nafiul,ALI MOHAMMOD,Kiraga Shafik,김용주,정선옥 한국농업기계학회 2022 바이오시스템공학 Vol.47 No.1

Purpose Overturning on uneven and sloped surfaces is an important issue during the operation of agricultural field machinery. In this study, the geometrical (size and location) parameters of a pepper transplanter under development were optimized by theoretical overturning analysis to maintain stability during the operation. Methods A walking-type transplanter was designed to transplant pepper seedlings in a two-row cultivation pattern so that the transplanting could be completed using three primary mechanisms for seeding, i.e., supply, picking, and dibbling. The four-wheel transplanter was designed to work with three different forward speeds (i.e., 0.3m/s, 0.65 m/s, and 1.3 m/s). Mathematical and 3-D models were constructed both for static and dynamic conditions, and simulation was performed using a commercial software package to minimize the overturning tendency of the transplanter. Results Considering the plant ridge height and width, the track width and wheelbase of the transplanter were determined to be 725mmand 680mm, respectively. The positions of the mechanisms were optimized to maintain the center of gravity (CG) of the transplanter in the middle point of the stability area with a 436.26 mm height from the ground. During the static analysis, the transplanter was overturned laterally and longitudinally at slope angles of 40.67° and 36.26°, respectively. The transplanter overturned when the angles exceeded 29.3° for uphill and 49° for downhill paths, respectively, at the maximum forward speed (1.3 m/s) during dynamic analysis. Also, lateral overturning occurred while one wheel was exposed to obstacles with heights greater than 245 mm at the maximum operating speed. Conclusions The results of this study would be helpful for designing the layout of the transplanter and the field test of the prototype.

Analysis and design of coding and interleaving in a MIMO-OFDM communication system

Iqbal, Zafar,Nooshabadi, S.,Heung-No Lee IEEE 2012 IEEE TRANSACTIONS ON CONSUMER ELECTRONICS - Vol.58 No.3

<P>Use of Wireless communications for Metropolitan Area Network (MAN) in consumer electronics has increased significantly in the recent past. This paper, presents the performance analysis of four different channel coding and interleaving schemes for MIMO-OFDM communications systems. A comparison is done based on the BER, hardware implementation resources requirement, and power dissipation. It also presents a memory-efficient and low-latency interleaver implementation technique for the MIMO-OFDM communication system. It is shown that among the four coding and interleaving schemes studied, the cross-antenna coding and per-antenna interleaving performs the best under all SNR conditions and for all modulation schemes. It is also the best scheme as far as the hardware resource implication and power dissipation are concerned, which are particularly important in the context of consumer electronics. Next, using the proposed interleaver, a MIMO-OFDM based transmitter employing a double data stream 2×2 MIMO spatial multiplexing system is built.</P>

Dual-hop Cooperation Protocol for Spectrum Sensing in Cognitive Radio Networks

Zafar Iqbal,Heung-No Lee 대한전자공학회 2017 대한전자공학회 학술대회 Vol.2017 No.1