United States Nuclear Regulatory Commission - Protecting People and the Environment

Analysis of the Control Rod Drop Accident (CRDA) for Lungmen ABWR (NUREG/IA-0455)

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Publication Information

Manuscript Completed: April 2015
Date Published: August 2015

Prepared by:
Chunkuan Shih*, Ai-Ling Ho*, Jong-Rong Wang*, Hao-Tzu Lin, Show-Chyuan Chiang**,
Chia-Chuan Liu**

Institute of Nuclear Energy Research, Atomic Energy Council, R.O.C.
1000, Wenhua Rd., Chiaan Village, Lungtan, Taoyuan, 325, Taiwan

*Institute of Nuclear Engineering and Science, National Tsing Hua University
101 Section 2, Kuang Fu Rd., HsinChu, Taiwan

**Department of Nuclear Safety, Taiwan Power Company
242, Section 3, Roosevelt Rd., Zhongzheng District, Taipei, Taiwan

K. Tien, NRC Project Manager

Division of Systems Analysis
Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

Prepared as part of:
The Agreement on Research Participation and Technical Exchange
Under the Thermal-Hydraulic Code Applications and Maintenance Program (CAMP)

Published by:
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

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The purpose of this report is to understand the realistic behavior in Lungmen ABWR (Advanced Boiling Water Reactor) during a control rod drop accident (CRDA) transient. The CRDA transient would lead the reactor through an extremely fast and localized power excursion, requiring an accurate core modeling. The CRDA analysis for Lungmen ABWR was performed by coupling the 3D neutron kinetic code, PARCS, and two-phase thermal-hydraulic (T-H) code, TRACE. After TRACE/PARCS coupling calculation, the output data from TRACE/PARCS would be putted into FRAPTRAN code as boundaries, such as a function of time-dependent fuel rod power and coolant boundary conditions, to calculate the fuel damage. The CRDA analysis for Lungmen ABWR was performed for two conditions: a) case1: hot-full-power (HFP) at beginning of cycle (BOC); b) case2: hot-zero-power (HZP) at BOC. Under these conditions, the damage mechanisms of fuel rod are: 1) cladding ballooning and burst; 2) embrittlement and failure by high-temperature oxidation; 3) melting of cladding and/or fuel pellets. And the relevant quantities for fuel performance are the maximum fuel enthalpy and the melting temperatures of cladding and fuel pellet. The results of CRDA analysis show that a) case1: no fuel failure occurs under HFP condition at BOC; b) case2: the fuel rod nearby the dropped control rod failed under HZP condition at BOC, and the FRAPTRAN data exposes that the main reason of rod failure is the cladding high temperature.

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