scholarly journals Mark 60B blanket tube failure

1975 ◽  
Author(s):  
M.K. Carlson
Keyword(s):  
2020 ◽  
Vol 7 (3) ◽  
pp. 19-00548-19-00548
Author(s):  
Akihiro UCHIBORI ◽  
Hideki YANAGISAWA ◽  
Takashi TAKATA ◽  
Jiazhi LI ◽  
Sunghyon JANG

Author(s):  
David Cho ◽  
Danny H. B. Mok ◽  
Steven X. Xu ◽  
Douglas A. Scarth

Technical requirements for analytical evaluation of in-service Zr-2.5Nb pressure tubes in CANDU(1) reactors are provided in the Canadian Standards Associate (CSA) N285.8. The evaluation must address all in-service degradation mechanisms including the presence of in-service flaws. Flaws found during in-service inspection of CANDU Zr-2.5Nb pressure tubes, including fuel bundle scratches, debris fretting flaws, fuel bundle bearing pad fretting flaws, dummy bundle bearing pad fretting flaws, erosion-shot flaws and crevice corrosion flaws, are volumetric and blunt in nature. These in-service flaws can become crack initiation sites during pressure tube operation and potentially lead to pressure tube failure. Any detected flaws that do not satisfy the criteria of acceptance as per CSA N285.4 must be analytically evaluated to justify continued operation of the pressure tube. Moreover, the risk of pressure tube failure due to presence of in-service flaws in the entire reactor core must be assessed. A review of assessment of the risk of pressure tube failure due to presence of in-service flaws in CANDU reactor core is provided in this paper. The review covers the technical requirements in the CSA N285.8 for evaluating degradation mechanisms related to flaws in the reactor core. Current Canadian industry practice of probabilistic assessment of reactor core for pressure tube failure due to presence of in-service flaws is described, including evaluation of flaws for crack initiation, subsequent crack growth to through-wall penetration, and pressure tube rupture due to unstable crack growth prior to safe shutdown of the reactor. Operating experience with the application of probabilistic assessment of reactor core for the risk of pressure tube failure due to presence of in-service flaws is also provided.


Author(s):  
Akihiro Uchibori ◽  
Shin Kikuchi ◽  
Akikazu Kurihara ◽  
Hirotsugu Hamada ◽  
Hiroyuki Ohshima

Multiphysics analysis system was newly developed to evaluate possibility of failure propagation occurrence under heat transfer tube failure accident in a steam generator of sodium-cooled fast reactors. The analysis system consists of the computer codes, SERAPHIM, TACT, RELAP5, which are based on the mechanistic numerical models. The SERAPHIM code calculates the multicomponent multiphase flow involving sodium-water chemical reaction. In this study, numerical models for the chemical reaction about production of a sodium monoxide and its transport process were constructed to enable evaluation of a wastage environment. The TACT code was developed to calculate heat transfer from the reacting jet to the adjacent tube and to predict the tube failure occurrence. The TACT code was integrated by the numerical models of the fluid-structure thermal coupling, the temperature and stress evaluation, the wastage evaluation and the failure judgment. The RELAP5 code evaluates thermal hydraulic behavior of water inside the tube. The original heat transfer correlations were corrected for the rapidly heated tube in the present work.


2015 ◽  
Vol 30 (2) ◽  
pp. 187
Author(s):  
Rakesh Kumar ◽  
AnilKumar Pandey ◽  
Sellam Karunanithi ◽  
ChetanD Patel ◽  
SanjayKumar Sharma ◽  
...  

Author(s):  
Jianxin Zhu ◽  
Xuedong Chen ◽  
Zhibin Ai ◽  
Weihe Guan

Hydrogenator feed tube furnace is of great safety concern due to its rigorous operation condition (up to 550°C, 17MPa) and flammable/explosive materials (H2, crude oil) involved in refining installations. Unlike instruments where the failure may not necessarily cause direct hazards, the failure of tubes in high temperature furnace always cause severe damage and downtime-caused economic loss. Normally the main cause of tube failure is time-dependent material degradation mechanism (such as creep, fatigue and oxidation). The occurrence of two tube rupture accidents gives birth to the consideration whether it is necessary to add a new isolation/mitigation layer in tube furnace in order to control time dependent risks. Taking advantage of the progress of life and probability prediction techniques (such as API581), the time-dependent risk of high pressure tube furnace was studied by taking into account of contributions provided by control system and safety instrumented functions (SIF). The frequency of severe initial events (leakage or rupture) of furnace tube was studied and fault tree analysis method was used to analyze the combined failure probability of time-dependent tube failure rate, basic process control system (BPCS) as well as safety instrumented system (SIS). The necessity of adding a mitigation function to reduce consequence caused by tube failure (leakage or rupture) was studied in order to control time dependent risks. A mitigation SIF at tube’s late service stage to reduce risks was proposed, which is of great significance for furnace safety.


Sign in / Sign up

Export Citation Format

Share Document