scholarly journals Regulatory analysis for the resolution of generic issue C---8, main steam isolation valve leakage and LCS (leakage control system) failure

1990 ◽  
Author(s):  
C Graves
Keyword(s):  
Control System ◽  
System Failure ◽  
Leakage Control ◽  
Valve Leakage ◽  
Regulatory Analysis ◽  
Main Steam

Anticipated Transient Without Scram Analysis for an ABWR Using RETRAN

2008 ◽  
Author(s):  
Chiung Wen Tsai ◽  
Shu Ming Yang ◽  
Chunkuan Shih ◽  
Jong-Rong Wang ◽  
Shao Shih Ma ◽  
...  
Keyword(s):  
High Pressure ◽  
Control System ◽  
Neutron Flux ◽  
Transient Analysis ◽  
Valve Closure ◽  
The Third ◽  
The Core ◽  
Main Steam ◽  
High Neutron ◽  
High Neutron Flux

A RETRAN02/MOD5 model was developed for Lungmen ABWR and applied for ATWS transient analysis. Three ATWS events including Main Steam Isolation Valve Closure (MSIVC), Loss of Offsite Power (LOOP), and Inadvertent Opening of all Turbine Bypass Valves (IOTBV) are analyzed in this study. During the first two transients, the vessel pressure is increased as a result of steam flow reduction due to the closure of main steam isolation valves (MSIVs) and Turbine Control Valves (TCVs) respectively. In the third transient, the vessel pressure is reduced because of the open of Turbine Bypass Valves (TBVs) and turns to be increased because of the closure of MSIVs. All of the above transients suffer high neutron flux as a result of void reduction. There are several equipments and procedures to mitigate ATWS transient such as feedwater trip, Reactor Internal Pumps (RIPs) runback and trip, and the depressurization of relief valves. After the ATWS high pressure signal is initiated and permissive for 180 seconds, Standby Liquid Control system is initiated to inject boron liquid into upper plenum to shutdown the reactor. The results conclude that equipments and procedures mitigate the event effectively and the core is brought to shutdown state.

Application of Earthquake Experience Data as Part of the Seismic Verification of Modified Main Steam Isolation Valve Leakage Pathway Piping

2004 ◽  
Author(s):  
Timothy M. Adams ◽  
Scott Quiggle
Keyword(s):  
Control Systems ◽  
Radioactive Iodine ◽  
Leakage Rate ◽  
Original Design ◽  
System A ◽  
Gas System ◽  
Group Report ◽  
Valve Leakage ◽  
Main Steam ◽  
Steam System

The Monticello Nuclear Generating Plant made modifications to the turbine island in 1998 to achieve a 5% power uprate. The radiological analysis conducted for power uprate took credit for deposition and holdup of radioactive iodine in the steam lines downstream of the Main Steam Isolation Valves (MSIV’s) and in the main condenser. The original design basis of certain main steam system piping, equipment, and components that comprise the MSIV Leakage Pathway was not in accordance with Seismic Category I requirements. As part of the original program seismic verification walkdowns were performed to demonstrate the main steam system piping, equipment, and components were seismically rugged. The walkdowns were done using the methodology suggested to seismically evaluate this pathway in the Boiling Water Reactor Owners’ Group report, entitled “BWROG Report of Increasing MSIV Leakage Rate Limits and Elimination of Leakage Control Systems”. In 2001, Monticello made significant changes to improve the performance of the plants hydrogen recombiner process. The hydrogen recombiners are part of the off gas system a portion of which was in the original MSIV Leakage Pathway. These modifications significantly redefined MSIV Leakage Pathway and required an updated assessment of the seismic ruggedness of piping and associated equipment in the MSIV Leakage Pathway. This paper describes the approach and methodology used to update and expand the seismic evaluations and seismic verification walkdowns. It also summarizes the results of these walkdowns and the steps necessary to demonstrate the seismic adequacy of the piping and equipment.

Performance and Operation Analysis of a Quadra Sectors Rotary Airheater Adopted by CFB Boiler

2014 ◽  
Vol 1070-1072 ◽  
pp. 1764-1768
Author(s):  
Zhan Guo Li ◽  
Zhen Ning Zhao ◽  
Zhi Qiang Wen
Keyword(s):  
Thermal Properties ◽  
Control System ◽  
Fluidized Bed ◽  
Circulating Fluidized Bed ◽  
Air Leakage ◽  
Circulating Fluidized Bed Boiler ◽  
Cfb Boiler ◽  
Operation Analysis ◽  
Operation Modes ◽  
Leakage Control

Based on the aspects of thermal properties, resistance properties, air Leakage Control and boiler output adaptability, the operation modes and their impact of a quad-sector rotary airheater adopted by a 330MWe circulating fluidized bed boiler are analyzed by tests. And the operation methods of Leakage Control System are concluded. In order to improve the reliability of rotary airheater with main and auxiliary motors, recommendations for improvement are extended.

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