Comparison and Reference Between RSE-M and ASME Section XI Regulations on In-Service Inspection for China Nuclear Power Plant

Author(s):  
Sun Haitao ◽  
Zhang Qinghua ◽  
Jia Panpan ◽  
Ling Ligong ◽  
Wang Chen ◽  
...  

RSE-M and ASME Section XI regulations are currently recognized as NPP ISI regulations which are most extensively used, most detailed in content and most mature in technology in the world. In China, RSE-M or ASME section XI regulations are used to guide the ISI program preparation, ISI activities implementation and management. There are many differences between RSE-M and ASME Section XI regulations, such as application of regulation, scope of application, main frame and content, basic requirements of ISI, acceptance and evaluation of ISI results, repairing and change. At the same time, some technical clauses can be used for reference by each other, such as qualification and inspection items. By comparison of RSE-M and ASME Section XI regulations for in-service inspection rules of China pressurized water reactor power plant, the technical differences between the two rules are analyzed. Combined with application and engineer practices for in-service inspection of China nuclear power plant, some technical terms used for mutual reference are summarized to provide assistance for establishing the in-service inspection program and specific implementation. During ISI activity, applicable regulation should be chosen according to the requirements of design in consideration of inspection items, examination methods, defect acceptance criteria and evaluation. Meanwhile, implementation of RSE-M and ASME Section XI regulations should be combined with the design features, experience feedback and aging management of mechanical equipment, and draw lessons from mature technical clauses of other regulations.

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Xu Zhang ◽  
Zhiguang Deng ◽  
Jun Li ◽  
Youwei Yang ◽  
Quan Ma ◽  
...  

As key equipment in nuclear power plant, the reactor power control system is adopted to strictly control and regulate the reactor power of a PWR (pressurized water reactor) in a nuclear power plant. A well-optimized predictive control algorithm based on SDMC (stepped dynamic matrix controller) is developed and introduced in this paper and applied to the power regulation of a reactor power model. In addition, the test and verification of this application is conducted by two different methods and devices: the virtual verification platform and the physical DCS (digital control system). The result of the verification suggests that the application of SDMC gains a better performance in the maximum dynamic deviation, adjustment time, overshoot, and so on.


Radiocarbon ◽  
1995 ◽  
Vol 37 (2) ◽  
pp. 497-504 ◽  
Author(s):  
Mihály Veres ◽  
Ede Hertelendi ◽  
György Uchrin ◽  
Eszter Csaba ◽  
István Barnabás ◽  
...  

We measured airborne releases of 14C from the Paks Pressurized Water Reactor (PWR) Nuclear Power Plant (NPP). Two continuous stack samplers collect 14C in 14CO2 and 14CnHm chemical forms. 14C activities were measured using two techniques; environmental air samples of lower activities were analyzed by proportional counting, stack samples were measured by liquid scintillation counting. 14C concentration of air in the stack varies between 80 and 200 Bqm−3. The average normalized yearly discharge rates for 1988–1993 were 0.74 TBqGW−1ey−1 for hydrocarbons and 0.06 TBqGW−1ey−1 for CO2. The discharge rate from Paks Nuclear Power Plant is about four times higher than the mean discharge value of a typical Western European PWR NPP. The higher 14C production may be apportioned to the higher level of nitrogen impurities in the primary coolant. Monitoring the long-term average excess from the NPP gave D14C = 3.5‰ for CO2 and D14C = 20‰ for hydrocarbons. We determined 14C activity concentration in the primary coolant to be ca. 4 kBq liter−1. The 14C activity concentrations of spent mixed bed ion exchange resins vary between 1.2 and 5.3 MBqkg−1 dry weight.


Author(s):  
Hsoung-Wei Chou ◽  
Chin-Cheng Huang

The failure probability of the pressurized water reactor pressure vessel for a domestic nuclear power plant in Taiwan has been evaluated according to the technical basis of the USNRC’s new pressurized thermal shock (PTS) screening criteria. The ORNL’s FAVOR code and the PNNL’s flaw models are employed to perform the probabilistic fracture mechanics analysis based on the plant specific parameters of the domestic reactor pressure vessel. Meanwhile, the PTS thermal hydraulic and the probabilistic risk assessment data analyzed from a similar nuclear power plant in the United States for establishing the new PTS rule are applied as the loading condition. Besides, an RT-based regression formula derived by the USNRC is also utilized to verify the through-wall cracking frequencies. It is found that the through-wall cracking of the analyzed reactor pressure vessel only occurs during the PTS events resulted from the stuck-open primary safety relief valves that later reclose, but with only an insignificant failure risk. The results indicate that the Taiwan domestic PWR reactor pressure vessel has sufficient structural margin for the PTS attack until either the end-of-license or for the proposed extended operation.


Author(s):  
Emil Kichev ◽  
Ivan Ivanov ◽  
Kaliopa Mancheva ◽  
Yasen Petrov ◽  
Vesselina Vladimirova ◽  
...  

Refueling outages at the Kozloduy Nuclear Power Plant (KNPP) Units 5 and 6 are used to perform annual repairs and preventive maintenance activities, piping inspections, and test activities. A refueling outage at KNPP typically requires 60 days and occurs on an annual basis. Testing of safety systems at the KNPP Units 5 and 6 is an extensive exercise that results in multiple actuations of all components during each test and a relatively high number of component actuations each year. This results in equipment wear out issues that can lead to considerable component replacement and/or refurbishment. Numerous piping in-service inspections are conducted in locations where there has been no industry or plant-specific indications or failures, leading to unnecessary personnel exposure. KNPP is interested in using risk-informed (RI) approaches to reduce refueling outage length, piping inspections, testing, and exposure. KNPP is a four-loop Voda-Vodyanoi Energetichesky Reaktor (VVER) with a power level of 1000 MWe. Safety systems consist of three trains. The KNPP at-power probabilistic safety assessment (PSA) model includes internal and external events. It addresses the full range of events leading to core damage frequency (CDF) and includes a simplified level 2 model leading to large early release frequency (LERF). The RI approach, as defined in the U.S. Nuclear Regulatory Commission’s (NRC’s) risk-informed (RI) Regulatory Guides (RGs) 1.174, 1.177, and 1.178, was used in this program. The specific approach used for risk-informed in-service inspection (RI-ISI) is based on the Pressurized Water Reactor Owner’s Group methodology. The overall approach for each of the three applications used a multi-step process which included the following: identification of systems to address; identification of alternatives to current maintenance, inspection, and testing practices; a risk assessment of the proposed alternatives; an assessment of the impact of the changes on deterministic considerations; identification of monitoring requirements; and an assessment of the economic benefits. The RI-ISI program also considered the impact of the changes on personnel exposure. The overall approach made extensive use of data assessments, reliability methods, and risk assessments. The results demonstrated that the proposed changes in maintenance, in-service inspection, and testing programs have a small impact on risk, based on CDF and LERF. In addition, the proposed changes provide significant benefits in terms of reduced outage time, in-service inspections, testing requirements, and personnel exposure. The economic analysis demonstrated that changes to the maintenance program provide the largest benefit followed by the changes to the in-service inspection program and then the changes to the testing program.


2016 ◽  
Vol 2016 ◽  
pp. 1-4 ◽  
Author(s):  
Mahdi Rezaeian ◽  
Jamshid Kamali

Due to high radioactivity and significant content of medium- and long-lived radionuclides, different operations with spent nuclear fuels (e.g., handling, transportation, and storage) shall be accompanied by suitable radiation protections. On the other hand, determination of radioactive source specification is the initial step for any radiation protection design. In this study, radioactive source specification of the spent fuels of Bushehr nuclear power plant, which is a VVER-1000 type pressurized water reactor, was determined. For the depletion and decay calculations, ORIGEN code was utilized. The results are presented for burnups of 30 to 49 GWd/MTHM and different cooling times up to 100 years. According to these results, total activity of a spent fuel assembly with initial enrichment of 3.92%, burnup of 49 GWd/MTHM, and cooling time of 3 years is 1.92 × 1016 Bq. The results can be utilized specifically in transportation/storage cask design for spent fuel management of Bushehr nuclear power plant.


2020 ◽  
Vol 329 ◽  
pp. 03049
Author(s):  
Aleksey Babushkin ◽  
Sergey Skubienko ◽  
Ludmila Kinash

In this study, the influence of the cooling water temperature on the thermal efficiency of a conceptual pressurized-water reactor nuclear- power plant is studied. The change in the cooling water temperature can be experienced due to the seasonal changes in climatic conditions at plant site. The article presents the results of technical and economic parameters study of nuclear power unit’s operation under increased vacuum value. Investigated seasonal variations of cooling water temperature, cooling water temperature influence on the vacuum temperature in the turbine condenser, and changing the basic technical and economic performance of nuclear power station. The mathematical model of calculation the nuclear power plant operation for a 1000 MW power unit was developed.


Author(s):  
Liu Lili ◽  
Zhang Ming ◽  
Deng Jian

A severe accident code was applied for modeling of a typical pressurized water reactor (PWR) nuclear power plant, and the effects of RCS depressurization on the gas temperature of the relief tank cell in the containment during a station blackout (SBO) induced accident was analyzed. The sensitivity calculation indicated that the hydrogen generation rate obviously increased due to RCS depressurization in a critical stage. The results show that RCS depressurization can play an important role in hydrogen generation rate and total accumulation, and the temperature of the containment atmosphere is highly influenced by hydrogen combustion. High temperature induced by hydrogen combustion may degrade the equipment and instruments capabilities. Based on this analysis, a feasible strategy of RCS depressurization for mitigating the accident consequence is provided for developing the capacity of the SBO treatment of Qinshan Phase Nuclear Power Plant (QSP-II NPP).


2021 ◽  
Author(s):  
Jin Feng Huang

Abstract After Fukushima nuclear power plant disaster, the efforts to overcome these defects of PWRs were carried out, such as replacing the cladding and fuel materials. One of these feasible efforts is using Fully Ceramic Microencapsulated (FCM) fuel replacement traditional UO2 pellets fuel into PWR. The FCM fuels are composed of Tri-structural-isotropic (TRISO) particles embedded in silicon carbide matrix. The TRISO fuel can hold its containment integrity and without fission production releases under the design temperature limit of 1600 °C. Furthermore, the silicon carbide matrix will benefit the thermal conductivity, radiation damage resistance, environmental stability and proliferation resistance. Consequently, the safety of the reactor could be significantly improved with FCM fuel instead of the conventional UO2 pellet fuel in PWR. We also analyzed the temperature distribution for the FCM fuel compared the traditional UO2 pellets, the calculation indicated that the centerline temperature is lower than UO2 pellets due to FCM higher thermal conductivity. The calculation demonstrated that, utilizing FCM replacement of conventional UO2 fuel rod is feasible and more security in a small pressurized water reactor. In this paper, a small pressurized water reactor utilizing FCM fuel is considered. A 17 × 17 fuel assemblies with Zircalloy cladding was applied in conceptual design through a preliminary neutronics and thermal hydraulics analysis. The reactor physics is accomplished, including the refuel cycle length, the effective multiplication factor, power distribution analysis being discussed. The Soluble Boron Free (SBF) concepts are introduced in small PWR, as a result, it makes the nuclear power plant more simpler and economical. FCM fuel loading has a very high excess reactivity at the beginning of reactor core life, and it is important to flat reactivity curve during operation, or to minimize excess reactivity during the core life. Consequently, conventional burnable poison configurations were introduced to suppress excess reactivity control at beginning of cycle.


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