Flow Blockage Accident Analysis of Tehran Research Reactor Fuel Assembly
Tehran Research Reactor (T.R.R.) is a pool-type, 5 MW thermal research reactor. One probable event is that if some external objects or debris fall down into the reactor core and cause obstruction of the coolant flow through one of the fuel assemblies, decreasing the surface flow area, ceases the coo...
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| Format: | Article |
| Language: | fas |
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Nuclear Science and Technology Research Institute
2011-02-01
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| Series: | مجله علوم و فنون هستهای |
| Subjects: | |
| Online Access: | https://jonsat.nstri.ir/article_437_8667836d168aabdf7621ea0fa18e83bd.pdf |
| _version_ | 1797834600970452992 |
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| author | J. Jafari S Khakshournia |
| author_facet | J. Jafari S Khakshournia |
| author_sort | J. Jafari |
| collection | DOAJ |
| description | Tehran Research Reactor (T.R.R.) is a pool-type, 5 MW thermal research reactor. One probable event is that if some external objects or debris fall down into the reactor core and cause obstruction of the coolant flow through one of the fuel assemblies, decreasing the surface flow area, ceases the coolant flow, and also raises the fuel and sheaths temperature. Thermal hydraulic analysis of this event has been studied using RELAP5 system code. This report is related to the partial and total obstruction of a single Fuel Element (F.E.) and cooling channel of 27 F.E. equilibrium core of the T.R.R. Such event may lead to severe accident for such type of research reactors, since it may cause a local dry out and eventually loss of the F.E. integrity. Two scenarios are analysed in order to emphasize the severity of the mentioned accident. The first is a partial blockage of hot F.E. which is considered for four different obstruction levels of the nominal flow area: 25%, 50%, 75% and 93%. The second is related to an extreme case which consists of the total blockage of the same F.E. The reactor power is derived through the kinetic point calculation in the RELAP5 code. The point kinetic feedbacks including the fuel temperature (Doppler coefficient) and the coolant density coefficient have been considered through the applied model. The main results obtained from the RELAP5 calculations are as follows: 1. In case when the flow blockage is under 93% of the nominal flow area of an average F.E., only the increase of the coolant and clad temperatures are observed with no integrity of the F.E. consequences. The mass flow rate remains sufficient enough and cools the clad safely 2. In the case of a total obstruction in the nominal flow area, it is seen that the severe accident is due to dryout conditions and reaches promptly, while melting of the cladding occurs. |
| first_indexed | 2024-04-09T14:41:21Z |
| format | Article |
| id | doaj.art-860465bb45164e6eb761adb932a65aa9 |
| institution | Directory Open Access Journal |
| issn | 1735-1871 2676-5861 |
| language | fas |
| last_indexed | 2024-04-09T14:41:21Z |
| publishDate | 2011-02-01 |
| publisher | Nuclear Science and Technology Research Institute |
| record_format | Article |
| series | مجله علوم و فنون هستهای |
| spelling | doaj.art-860465bb45164e6eb761adb932a65aa92023-05-03T08:04:43ZfasNuclear Science and Technology Research Instituteمجله علوم و فنون هستهای1735-18712676-58612011-02-013145762437Flow Blockage Accident Analysis of Tehran Research Reactor Fuel AssemblyJ. Jafari0S Khakshournia1Reactors and Accelerators R & D School, Nuclear Science and Technology Research Institute, P.O. Box: 1439951113, Teheran- IranReactors and Accelerators R & D School, Nuclear Science and Technology Research Institute, P.O. Box: 1439951113, Teheran- IranTehran Research Reactor (T.R.R.) is a pool-type, 5 MW thermal research reactor. One probable event is that if some external objects or debris fall down into the reactor core and cause obstruction of the coolant flow through one of the fuel assemblies, decreasing the surface flow area, ceases the coolant flow, and also raises the fuel and sheaths temperature. Thermal hydraulic analysis of this event has been studied using RELAP5 system code. This report is related to the partial and total obstruction of a single Fuel Element (F.E.) and cooling channel of 27 F.E. equilibrium core of the T.R.R. Such event may lead to severe accident for such type of research reactors, since it may cause a local dry out and eventually loss of the F.E. integrity. Two scenarios are analysed in order to emphasize the severity of the mentioned accident. The first is a partial blockage of hot F.E. which is considered for four different obstruction levels of the nominal flow area: 25%, 50%, 75% and 93%. The second is related to an extreme case which consists of the total blockage of the same F.E. The reactor power is derived through the kinetic point calculation in the RELAP5 code. The point kinetic feedbacks including the fuel temperature (Doppler coefficient) and the coolant density coefficient have been considered through the applied model. The main results obtained from the RELAP5 calculations are as follows: 1. In case when the flow blockage is under 93% of the nominal flow area of an average F.E., only the increase of the coolant and clad temperatures are observed with no integrity of the F.E. consequences. The mass flow rate remains sufficient enough and cools the clad safely 2. In the case of a total obstruction in the nominal flow area, it is seen that the severe accident is due to dryout conditions and reaches promptly, while melting of the cladding occurs.https://jonsat.nstri.ir/article_437_8667836d168aabdf7621ea0fa18e83bd.pdftehran research reactorblockage of flowfuel elementrelap5 code |
| spellingShingle | J. Jafari S Khakshournia Flow Blockage Accident Analysis of Tehran Research Reactor Fuel Assembly مجله علوم و فنون هستهای tehran research reactor blockage of flow fuel element relap5 code |
| title | Flow Blockage Accident Analysis of Tehran Research Reactor Fuel Assembly |
| title_full | Flow Blockage Accident Analysis of Tehran Research Reactor Fuel Assembly |
| title_fullStr | Flow Blockage Accident Analysis of Tehran Research Reactor Fuel Assembly |
| title_full_unstemmed | Flow Blockage Accident Analysis of Tehran Research Reactor Fuel Assembly |
| title_short | Flow Blockage Accident Analysis of Tehran Research Reactor Fuel Assembly |
| title_sort | flow blockage accident analysis of tehran research reactor fuel assembly |
| topic | tehran research reactor blockage of flow fuel element relap5 code |
| url | https://jonsat.nstri.ir/article_437_8667836d168aabdf7621ea0fa18e83bd.pdf |
| work_keys_str_mv | AT jjafari flowblockageaccidentanalysisoftehranresearchreactorfuelassembly AT skhakshournia flowblockageaccidentanalysisoftehranresearchreactorfuelassembly |