scholarly journals Development of a criterion to record the facts of fuel carryover from leaking fuel elements during VVER reactor operation

2020 ◽  
Vol 2020 (3) ◽  
pp. 50-61
Author(s):  
Igor’ Anatol’evich Evdokimov ◽  
Andrey Grigorievich Khromov ◽  
Peter Mikhajlovich Kalinichev ◽  
Vladimir Valentinovich Likhanskij ◽  
Aleksey Anatolievich Kovalishin ◽  
...  
Keyword(s):  
Vver Reactor ◽  
Reactor Operation ◽  
Fuel Elements

scholarly journals KAJIAN KESELAMATAN PENGOPERASIAN REAKTOR TRIGA 2000 BANDUNG DENGAN MENGGUNAKAN BATANG KENDALI REAKTOR TRIGA 2000 TANPA BAHAN BAKAR (BKRTTBB)

2015 ◽  
Vol 16 (2) ◽  
pp. 93
Author(s):  
Prasetyo Basuki ◽  
A.R. Iso Suwarso ◽  
Agus Sunarya ◽  
P. Ilham Yazid ◽  
Mr. Supardjo ◽  
...  
Keyword(s):  
Water Temperature ◽  
Power Factor ◽  
Peak Power ◽  
Reactor Operation ◽  
Primary Coolant ◽  
Control Rod ◽  
Channel Temperature ◽  
Temperature Exchange ◽  
Post Modification ◽  
Fuel Elements

ABSTRAKKAJIAN KESELAMATAN PENGOPERASIAN REAKTOR TRIGA 2000 BANDUNG DENGAN MENGGUNAKAN BATANG KENDALI REAKTOR TRIGA 2000 TANPA BAHAN BAKAR (BKRTTBB). Telah dilakukan kegiatan pabrikasi BKRTTBB untuk digunakan pada teras TRIGA 2000 Bandung sebagai upaya modifikasi batang kendali pengganti FFCR (Fuel Follower Control Rod) yang telah memiliki fraksi bakar melebihi 50% pada bagian elemen pengikutnya. Dari 5 buah FFCR yang digunakan saat ini telah terindikasi 2 buah yang memiliki fraksi bakar melebihi 50 % dan 1 buah yang telah mendekati 50 %. Sampai dengan akhir tahun ini direncanakan dilakukan penggantian sebanyak 2 buah, dan akan berlanjut sampai dengan 4 buah di tahun berikutnya. Untuk dapat menjamin keselamatan proses modifikasi dan pasca modifikasi, maka perlu dilakukan kajian simulasi operasi dengan menggunakan BKRTTBB pada skenario teras paling reaktif. Pada kajian ini telah dilakukan simulasi operasi dengan meng-gunakan 1 buah FFCR, 4 buah BKRTTBB, dan 102 elemen bakar dengan komposisi elemen bakar sesuai dengan kondisi terkini pada teras TRIGA 2000 dengan menggunakan MCNP. Dari kajian ini didapatkan beberapa parameter kritikalitas antara lain reaktivitas teras lebih (core excess) sebesar $ 5,461, dan reaktivitas padam (shutdown margin) sebesar $ -9,647, kemudian dengan menskenariokan kondisi one stuck rod didapatkan bahwa semua kondisi salah satu batang kendali tersangkut memberikan respons subkritis. Kemudian dari simulasi ini pula di-dapatkan faktor puncak daya aksial sebesar 1,21 dan faktor puncak daya radial sebesar 2,02. Dari kedua nilai faktor puncak daya ini dapat dihitung distribusi suhu pada teras dengan menggunakan program komputasi STAT dan STATMOD. Hasil simulasi menggunakan STAT dan STATMOD dengan memberikan suhu masukan air sampai dengan 42 °C didapatkan suhu terpanas pada subbuluh sebesar 87,98 °C dan 82,75 °C. Berdasarkan hasil ini dapat disimpul-kan bahwa pengoperasian reaktor dengan menggunakan BKRTTBB pada kondisi yang men-dekati dimana suhu air masukan mendekati 49 °C (suhu tertinggi untuk sinyal SCRAM), air pendingin primer belum mencapai suhu pendidihan (112 °C). Sehingga pengoperasian reaktor dengan BKRTTBB dapat dinyatakan aman dan selamat dari aspek neutronik maupun termal-hidrolik.ABSTRACTSAFETY REVIEW OF BANDUNG TRIGA 2000 RESEARCH REACTOR OPERATION USING CONTROL ROD WITHOUT FUEL FOLLOWER (BKRTTBB). BKRTTBB manufacturing activities have been carried out to be used on the TRIGA 2000 core as a modification of the control rod replacement FFCR (Fuel Follower Control Rod) which has had burnup exceeds 50 % on the fuel follower. Two units of existing FFCR have been indicated exceeds 50 % of burnup and 1 unit was approaching 50%. Until the end of this year planned replacement by 2 units, and will continue up to 4 units in the next year. To ensure the safety of the modification process and the post-modification activities, it is necessary to study the operation simulation using BKRTTBB on the most reactive core. This study has been carried out on simulated reactor operation using 1 unit FFCR, 4 units BKRTTBB, and 102 fuel elements with composition in accordance with current conditions on the TRIGA 2000 core by using MCNP. This study obtained some criticality parameters, core excess $ 5.461, and shutdown margin $ -9.647, then the scenario of one stuck rod conditions showed that all the conditions of one control rod stuck is responded as subcritical. Then from this simulation also obtained axial peak power factor of 1.21 and radial peak power factor of 2.02. Based on these values, the temperature distribution on the reactor can be calculated using computational codes, STAT and STATMOD. The simulation results using STAT and STATMOD by providing input water temperature up to 42 °C at the hottest sub channel temperature obtained of 87.98 °C and 82.75 °C. Based on these results it can be concluded that operation of the reactor by using BKRTTBB in conditions near to LOFA where no temperature exchange so that the water temperature input approaching 49 °C (the highest temperature for the scram signal), water primary coolant still has not reached the temperature of boiling (112 °C). So that the operation of the reactor with BKRTTBB can be declared safely and secure in neutronics and termalhydraulics aspect.

Investigations on potential methods for the long-term monitoring of the state of fuel elements in dry storage casks

Kerntechnik ◽  
2018 ◽  
Vol 83 (6) ◽  
pp. 513-522 ◽  
Author(s):  
U. Hampel ◽  
A. Kratzsch ◽  
R. Rachamin ◽  
M. Wagner ◽  
S. Schmidt ◽  
...  
Keyword(s):  
The State ◽  
Dry Storage ◽  
Long Term Monitoring ◽  
Potential Methods ◽  
Fuel Elements ◽  
Term Monitoring

Anaerobic/aerobic biodegradation of pentachlorophenol using GAC fluidized bed reactors: optimization of the empty bed contact time

1997 ◽  
Vol 36 (6-7) ◽  
pp. 107-115 ◽  
Author(s):  
Gregory J. Wilson ◽  
Amid P. Khodadoust ◽  
Makram T. Suidan ◽  
Richard C. Brenner
Keyword(s):  
Fluidized Bed ◽  
Oxygen Demand ◽  
Aerobic Biodegradation ◽  
Fluidized Bed Reactors ◽  
Reactor Performance ◽  
Reactor Operation ◽  
Significant Cost ◽  
Second Stage ◽  
Primary Substrate ◽  
Chlorinated Phenolic Compounds

An integrated reactor system has been developed to remediate pentachlorophenol (PCP) containing wastes using sequential anaerobic and aerobic biodegradation. Anaerobically, PCP was degraded to predominately equimolar concentrations (>99%) of monochlorophenol (MCP) in two GAC fluidized bed reactors at Empty Bed Contact Times (EBCTs) ranging from 18.6 to 1.15 hours. However, at lower EBCTs, MCP concentrations decreased to less than 10% of the influent PCP concentration suggesting mineralization. The optimal EBCT was determined to be 2.3 hours based on PCP conversion to MCPs and stable reactor operation. Decreasing the EBCT fourfold did not inhibit degradation of PCP and its intermediates, thus allowing removal of PCP at much lower detention time and resulting in a significant cost advantage. Analytical grade PCP was fed via syringe pumps into two fluidized bed reactors at influent concentrations of 100 mg/l and 200 mg/l, respectively. Acting as the primary substrate, ethanol was also fed into the reactors at concentrations of 697 and 1388 mg/l. Effluent PCP and chlorinated phenolic compounds were analyzed weekly to evaluate reactor performance. Biodegradation pathways were also identified. 3-chlorophenol (CP) was the predominant MCP and varied simultaneously with 3,5-dichlorophenol (DCP) concentrations. Likewise, 4-CP concentrations varied simultaneously with 3,4-DCP concentrations. A second stage aerobic GAC fluidized bed reactor was added after the anaerobic reactor to completely mineralize the remaining MCP and phenols. Data show no presence of phenol and MCP in the effluent or on the GAC. Overall, the chemical oxygen demand (COD) fed to the system was reduced from 75 g/d in the influent to less than 1.5 g/d in the effluent.

scholarly journals Continuous synthesis of gold nanoparticles in micro- and millifluidic systems

2018 ◽  
Vol 6 (3) ◽  
Author(s):  
He Huang ◽  
Hendrik du Toit ◽  
Luca Panariello ◽  
Luca Mazzei ◽  
Asterios Gavriilidis
Keyword(s):  
Gold Nanoparticles ◽  
Nanoparticle Synthesis ◽  
Reactor Operation ◽  
Design Procedures ◽  
Time Control ◽  
Starting Point ◽  
Quantitative Understanding ◽  
Gold Nanomaterials ◽  
Gold Nanoparticle Synthesis ◽  
Flow Devices

Abstract Gold nanomaterials have diverse applications ranging from healthcare and nanomedicine to analytical sciences and catalysis. Microfluidic and millifluidic reactors offer multiple advantages for their synthesis and manufacturing, including controlled or fast mixing, accurate reaction time control and excellent heat transfer. These advantages are demonstrated by reviewing gold nanoparticle synthesis strategies in flow devices. However, there are still challenges to be resolved, such as reactor fouling, particularly if robust manufacturing processes are to be developed to achieve the desired targets in terms of nanoparticle size, size distribution, surface properties, process throughput and robustness. Solutions to these challenges are more effective through a coordinated approach from chemists, engineers and physicists, which has at its core a qualitative and quantitative understanding of the synthesis processes and reactor operation. This is important as nanoparticle synthesis is complex, encompassing multiple phenomena interacting with each other, often taking place at short timescales. The proposed methodology for the development of reactors and processes is generic and contains various interconnected considerations. It aims to be a starting point towards rigorous design procedures for the robust and reproducible continuous flow synthesis of gold nanoparticles. Graphical Abstract:

scholarly journals Modeling of a Real-Life Industrial Reactor for Hydrogenation of Benzene Process

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 412
Author(s):  
Mirosław K. Szukiewicz ◽  
Krzysztof Kaczmarski
Keyword(s):  
Catalyst Activity ◽  
Real Life ◽  
Operating Conditions ◽  
Reactor Operation ◽  
Reactor Model ◽  
High Scale ◽  
Industrial Reactor ◽  
Knowledge Based ◽  
Operation Conditions ◽  
Insight Into

A dynamic model of the hydrogenation of benzene to cyclohexane reaction in a real-life industrial reactor is elaborated. Transformations of the model leading to satisfactory results are presented and discussed. Operating conditions accepted in the simulations are identical to those observed in the chemical plant. Under those conditions, some components of the reaction mixture vanish, and the diffusion coefficients of the components vary along the reactor (they are strongly concentration-dependent). We came up with a final reactor model predicting with reasonable accuracy the reaction mixture’s outlet composition and temperature profile throughout the process. Additionally, the model enables the anticipation of catalyst activity and the remaining deactivated catalyst lifetime. Conclusions concerning reactor operation conditions resulting from the simulations are presented as well. Since the model provides deep insight into the process of simulating, it allows us to make knowledge-based decisions. It should be pointed out that improvements in the process run, related to operating conditions, or catalyst application, or both on account of the high scale of the process and its expected growth, will remarkably influence both the profits and environmental protection.

scholarly journals Comparative Study for the Prediction of Cavitating Flow inside a Square-Edged Orifice using Different Commercial CFD Software

2019 ◽  
Vol 128 ◽  
pp. 06003
Author(s):  
Gong-Hee Lee ◽  
June-Ho Bae
Keyword(s):  
Structural Damage ◽  
Nuclear Power ◽  
Cavitating Flow ◽  
Regulatory Body ◽  
Reactor Operation ◽  
Flow Acceleration ◽  
Service Testing ◽  
Ansys Cfx ◽  
Rapid Flow ◽  
Computational Fluid Dynamics Cfd

Nuclear power plant operators conduct in-service testing (IST) to verify the safety functions of safety–related pumps and valves and to monitor the degree of vulnerability over time during reactor operation. The system to which the pump and valve to be tested are installed has various sizes of orificesfor flow control and decompression. Rapid flow acceleration and accompanying pressure drop may cause cavitation inside the orifice, which may result in orifice degradation and structural damage. Though licensing applications supported by using Computational Fluid Dynamics (CFD) software are gradually increasing for IST–related problems, there is no CFD software which obtains a licensing from the domestic regulatory body until now. In this paper, to assess the prediction performance of different commercialCFD software for the analysis of cavitating flow inside a square–edged orifice, the simulation was conducted with ANSYS CFX and FLUENT R18.1. The results predicted were then compared with the measured data.

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