• 제목/요약/키워드: LBLOCA Reflood

검색결과 21건 처리시간 0.053초

CORE THERMAL HYDRAULIC BEHAVIOR DURING THE REFLOOD PHASE OF COLD-LEG LBLOCA EXPERIMENTS USING THE ATLAS TEST FACILITY

  • Cho, Seok;Park, Hyun-Sik;Choi, Ki-Yong;Kang, Kyoung-Ho;Baek, Won-Pil;Kim, Yeon-Sik
    • Nuclear Engineering and Technology
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    • 제41권10호
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    • pp.1263-1274
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    • 2009

  • Several experimental tests to simulate a reflood phase of a cold-leg LBLOCA of the APR1400 have been performed using the ATLAS facility. This paper describes the related experimental results with respect to the thermal-hydraulic behavior in the core and the system-core interactions during the reflood phase of the cold-leg LBLOCA conditions. The present descriptions will be focused on the LB-CL-09, LB-CL-11, LB-CL-14, and LB-CL-15 tests performed using the ATLAS. The LB-CL-09 is an integral effect test with conservative boundary condition; the LB-CL-11 and -14 are integral effect tests with realistic boundary conditions, and the LB-CL-15 is a separated effect test. The objectives of these tests are to investigate the thermal-hydraulic behavior during an entire reflood phase and to provide reliable experimental data for validating the LBLOCA analysis methodology for the APR1400. The initial and boundary conditions were obtained by applying scaling ratios to the MARS simulation results for the LBLOCA scenario of the APR1400. The ECC water flow rate from the safety injection tanks and the decay heat were simulated from the start of the reflood phase. The simulated core power was controlled to be 1.2 times that of the ANS-73 decay heat curve for LB-CL-09 and 1.02 times that of the ANS-79 decay curve for LB-CL-11, -14, and -15. The simulated ECC water flow rate from the high pressure safety injection pump was 0.32 kg/s. The present experimental data showed that the cladding temperature behavior is closely related to the collapsed water level in the core and the downcomer.

  • https://doi.org/10.5516/NET.2009.41.10.1263 인용 PDF KSCI

MAJOR THERMAL-HYDRAULIC PHENOMENA FOUND DURING ATLAS LBLOCA REFLOOD TESTS FOR AN ADVANCED PRESSURIZED WATER REACTOR APR1400

  • Park, Hyun-Sik;Choi, Ki-Yong;Cho, Seok;Kang, Kyoung-Ho;Kim, Yeon-Sik
    • Nuclear Engineering and Technology
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    • 제43권3호
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    • pp.257-270
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    • 2011

  • A set of reflood tests has been performed using ATLAS, which is a thermal-hydraulic integral effect test facility for the pressurized water reactors of APR1400 and OPR1000. Several important phenomena were observed during the ATLAS LBLOCA reflood tests, including core quenching, down-comer boiling, ECC bypass, and steam binding. The present paper discusses those four topics based on the LB-CL-11 test, which is a best-estimate simulation of the LBLOCA reflood phase for APR1400 using ATLAS. Both homogeneous bottom quenching and inhomogeneous top quenching were observed for a uniform radial power profile during the LB-CL-11 test. From the observation of the down-comer boiling phenomena during the LB-CL-11 test, it was found that the measured void fraction in the lower down-comer region was relatively smaller than that estimated from the RELAP5 code, which predicted an unrealistically higher void generation and magnified the downcomer boiling effect for APR1400. The direct ECC bypass was the dominant ECC bypass mechanism throughout the test even though sweep-out occurred during the earlier period. The ECC bypass fractions were between 0.2 and 0.6 during the later test period. The steam binding phenomena was observed, and its effect on the collapsed water levels of the core and down-comer was discussed.

  • https://doi.org/10.5516/NET.2011.43.3.257 인용 PDF KSCI

Air-Water Test on the Direct ECC Bypass During LBLOCA Reflood Phase with DVI : UPTF Test 21-D Counterpart Test

  • Yun, Byong-Jo;Kwon, Tae-Soon;Song, Chul-Hwa;Euh, Dong-Jin;Park, Jong-Kyun;Cho, Hyoung-Kyu;Park, Goon-Cherl
    • Nuclear Engineering and Technology
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    • 제33권3호
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    • pp.315-326
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    • 2001

  • Direct ECC bypass phenomena that occur in a reactor vessel downcomer with a Direct Vessel Injection (DVI) system during the reflood phase of a Large Break Loss-of-Coolant Accident (LBLOCA) are experimentally investigated using a transparent l/7.5 scaled down test facility of the Upper Plenum Test Facility (UPTF). A series of separate effect tests are peformed in order to investigate the mechanisms of direct ECC bypass and to find out its scaling parameters. Various flow regimes and phasic distribution in downcomer are identified and mapped, and the fraction of direct ECC bypass is measured under a wide range of air and water injection conditions. From the counterpart test of the UPTF Test 21-D, the dimensionless gas velocity ( $j^{*}$$_{g,eff}$) is derived experimentally, which is believed to be a major scaling parameter for the fraction of direct ECC bypass. And it is found out that the direct ECC bypass is greatly affected by the spreading width of ECC water film and the geometric configuration of the downcomer.r.

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RELAP5 /MOD3 재관수 모델의 개선 및 평가 (Improvements to the RELAP5/MOD3 Reflood Model and Assessment)

  • 정법동;이영진;박찬억;최철진;황태석
    • Nuclear Engineering and Technology
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    • 제26권2호
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    • pp.265-276
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    • 1994

  • FLECHT-SEASET 실험에 대한 REIAP5/MOD3 평가시에 밝혀진 코드결함을 수정하기 위하여 RELAP5/MOD3 재관수 모델을 개선하였다. 모델개선은 재관수 열전달 모델의 수정과 분산유동영역의 액적 크기의 조절을 통하여 이루어졌으며 재관수 계산시 발생되는 압력 spike와 수위진동 등의 결함을 개선하기 위하여 벽면비등모델의 time-smoothing과 천이 유동시의 level tracking모델도 첨가되었다. FLECHT-SEASET 실험에 대한 개선모델의 검증과 발전소의 대형냉각재 상실 사고해석 응용에서 코드결함이 개선되었음을 알 수 있었다.

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