scholarly journals Single-Phase Natural Circulation in a PWR during a Loss of Coolant Accident

2020 ◽  
Author(s):  
Mohammed W. Abdulrahman ◽  
Mikdam M. Saleh ◽  
Jonathan Anand
Keyword(s):  
Single Phase ◽  
Natural Circulation ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant

scholarly journals Validation of Advanced Computer Codes for VVER Technology: LB-LOCA Transient in PSB-VVER Facility

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
A. Del Nevo ◽  
M. Adorni ◽  
F. D'Auria ◽  
O. I. Melikhov ◽  
I. V. Elkin ◽  
...  
Keyword(s):  
Natural Circulation ◽  
Test Facility ◽  
Pressurized Water Reactor ◽  
Pressurized Water ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Mass Inventory ◽  
Computer Codes ◽  
Set Up ◽  
Advanced Computer

The OECD/NEA PSB-VVER project provided unique and useful experimental data for code validation from PSB-VVER test facility. This facility represents the scaled-down layout of the Russian-designed pressurized water reactor, namely, VVER-1000. Five experiments were executed, dealing with loss of coolant scenarios (small, intermediate, and large break loss of coolant accidents), a primary-to-secondary leak, and a parametric study (natural circulation test) aimed at characterizing the VVER system at reduced mass inventory conditions. The comparative analysis, presented in the paper, regards the large break loss of coolant accident experiment. Four participants from three different institutions were involved in the benchmark and applied their own models and set up for four different thermal-hydraulic system codes. The benchmark demonstrated the performances of such codes in predicting phenomena relevant for safety on the basis of fixed criteria.

Modeling Passive Safety in the Westinghouse Small Modular Reactor: Assessment of Wall Condensation and CMT Natural Circulation

2013 ◽  
Author(s):  
Jun Liao ◽  
Vefa N. Kucukboyaci
Keyword(s):  
Natural Circulation ◽  
Passive Safety ◽  
Reactor Safety ◽  
Heat Transfer Mechanism ◽  
The Core ◽  
Design Basis ◽  
Loss Of Coolant Accident ◽  
Small Modular Reactor ◽  
Loss Of Coolant ◽  
Safety Design

Passive safety design that utilizes gravity, natural circulation, heat sink and stored potential energy for reactor safety functions is being increasingly adopted in advanced reactors, especially in the small modular reactor (SMR) designs. The passive safety design of the Westinghouse SMR is described in details and compared with the AP1000® passive safety design. The natural circulation loops and heat transfer mechanism in a postulated Westinghouse SMR loss of coolant accident (LOCA) are discussed. The key thermal hydraulic phenomena pertinent to the passive safety design of the Westinghouse SMR have been identified in the small break LOCA Phenomena Identification and Rank Table (PIRT). Among the identified phenomena, condensation on the containment wall and natural circulation in core makeup tank (CMT) loop are highly ranked. Those passive safety phenomena are expected to be assessed using the WCOBRA/TRAC-TF2 LOCA thermal hydraulic code, which will provide the design basis LOCA analysis in the SMR design control documentation. In this paper, the progress on the assessing two key phenomena in passive safety of Westinghouse SMR is reported. The preliminary assessments against UCB tube condensation tests and Westinghouse core makeup tank tests reveals the capability of WCOBRA/TRAC-TF2 code to reasonably predict the condensation on the containment wall and natural circulation in the core makeup tank (CMT) loop.

Best-Estimate Evaluation of Large-Break Loss-of-Coolant Accident for Advanced Natural Circulation Nuclear Reactor

2008 ◽  
Vol 160 (3) ◽  
pp. 318-333 ◽  
Author(s):  
Vivek Bhasin ◽  
A. Srivastava ◽  
R. Rastogi ◽  
H. G. Lele ◽  
K. K. Vaze ◽  
...  
Keyword(s):  
Nuclear Reactor ◽  
Natural Circulation ◽  
Best Estimate ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant

Transient Analysis for the Case of Changes in Coolant Inventory for Advanced Heavy Water Reactor

2004 ◽  
Author(s):  
H. G. Lele ◽  
A. Srivastava ◽  
B. Chatterjee ◽  
A. J. Gaikwad ◽  
Rajesh Kumar ◽  
...  
Keyword(s):  
Heavy Water ◽  
Nuclear Reactor ◽  
Natural Circulation ◽  
Reactor Core ◽  
Two Phase ◽  
Decay Heat ◽  
Loss Of Coolant Accident ◽  
Loss Of Coolant ◽  
Heavy Water Reactor ◽  
Core Cooling

Safety of nuclear reactor needs to be assessed against different categories of Postulated initiating events. Advanced Heavy Water Reactor is natural circulation light water cooled and heavy water moderated pressure tube type of reactor. Inventory of the system is important parameter in determination of flow characteristics of this natural circulation reactor. In view of this, various events that cause changes in PHT system inventory are analysed in this paper. One of the reason for decrease in coolant inventory is hypothetical Loss of coolant accident (LOCA) This event is of very low probability but important from designing engineered safeguard system of a reactor. Loss of coolant accident in a nuclear reactor can cause voiding of the reactor core due to expulsion of primary coolant from break. In such, a situation the reactor core experiences very low heat removal rate from the nuclear fuel though the decay heat generation continues even after tripping of the reactor. Heat generation in the reactor core is due to various sources such as decay heat, stored heat etc, can lead to heating of fuel elements. However, Emergency core cooling systems of the reactor are actuated and prevent undesirable temperature rise. These events are called design basis events and focus is on adequacy of Emergency Core Cooling System (ECCS) and fuel integrity. The scenarios, phenomena encountered and consequences depend upon size and location of break, system characteristics, and actuation and capability of different protection and engineered safeguard systems of the reactor system. Moreover, this reactor has several passive features to ensure safety of this reactor. which are considered in analyzing these events. Events under category of decrease in coolant inventory includes loss of coolant accidents due to break at different locations of different sizes. Various locations considered in this paper are steam line, inlet header, inlet feeder, ECCS header, downcomer, pressure tube, Isolation condenser inlet header, instrument line break at inlet header and steam drum. The paper also considers scenario emerging due to malfunctions like relief valve stuck open. Causes for events under category of increase in coolant inventory are Increase in Drum level controller set point, Inadvertent valving in of Accumulators and Inadvertent valving in of Gravity driven water pool (GDWP). Last two events are not analysed as they are not possible. The analysis for the above events is complex due to various complex and wide ranges of phenomena involved during different pies under this category. It involves single and two phase natural circulation at different power levels, inventories and pressures, two-phase natural circulation under depleted inventory conditions. Coupled neutronics and thermal hydraulics behaviour, Phenomena under LOCA, phenomena during ECCS injection, direct injection into fuel rod, advanced accumulator injection., vapour pull through and coupled controller and thermal hydraulics. Modelling of these phenomena for each event is discussed in this paper. In this paper summary of analyses for representive event is presented.

The Halting Process of Natural Circulation in Primary Circuit of Low Temperature Nuclear Heating Reactor

2012 ◽  
Vol 512-515 ◽  
pp. 874-877
Author(s):  
Xue Song Zhang ◽  
Zhi Ping Ju ◽  
Jun Rui Shi ◽  
Wei Zhe Li ◽  
Wen Ping Zhou
Keyword(s):  
Low Temperature ◽  
Natural Circulation ◽  
Primary Circuit ◽  
Nuclear Heating Reactor ◽  
Loss Of Coolant Accident ◽  
Burn Out ◽  
Loss Of Coolant ◽  
Nuclear Heating ◽  
Temperature Heating

Fluctuation of security and flux, when natural circulation was halted in primary circuit of low temperature nuclear heating reactor by experiment during small break loss of coolant accident was studied. This is one of disadvantage aspect to such system. The results of this paper was Heated component won’t burn out while SBLOCA in lower cone in low temperature heating reactor. It was valuable suggestions on the development of commercial nuclear heating reactor.

Validation of SAS4A/SASSYS-1 for predicting steady-state single-phase natural circulation

2021 ◽  
Vol 377 ◽  
pp. 111149
Author(s):  
Taiyang Zhang ◽  
Erik R. Smith ◽  
Caleb S. Brooks ◽  
Thomas H. Fanning
Keyword(s):  
Steady State ◽  
Single Phase ◽  
Natural Circulation
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