Outlook for the Requirements of the Nuclear Power Plant Irradiation Test in China SONG DANRONG Nuclear Power Institute of China

Outlook of nuclear development in China in 2050 The objective of nuclear fuel and material irradiation test Requirements of irradiation test of NPP in operation Contents Irradiation test of New NPP fuel elements Irradiation test of New NPP structure material

History and Status of Nuclear Power Development in China Qinshan Base Tianwan BaseDaya Bay Base 3 Nuclear Power Bases has been formed

返回本章首页 Planning of Nuclear Power Development in China In October 2007, the Medium- and Long-term Nuclear Power Development Program (2005—2020) issued.

Planning of Nuclear Power Development in China Targets: Reach 40 GWe installed capacity in operation and another 18 GWe under construction by The proportion of nuclear installed capacity will increase from the present less than 2% up to 4%. The annual output of nuclear power will reach 260~280 TWh.

Outlook of nuclear development in China in 2050 It’s hopeful to keep the nuclear energy in China on a sustainable and positive development in 21st century. Motivation:  The increase of electricity demand.  The need of keeping and improving national nuclear power, protecting national security.  Energy security should be guarantied.  Protect the environment and implement the strategy of sustainable development.

Outlook of nuclear development in China in 2050 Targets:  Reach 40 GWe installed capacity in operation and 18 GWe under construction by  Reach 70GWe capacity till 2050.

The objective of nuclear fuel and material irradiation test Objective: By 2050, dozens of these nuclear power units in China have been facing the problem of aging management and life extension, and both of which would make a series of demand on irradiation test.  For reactor materials: Know the change of reactor fuel performance during irradiation ； study the impact brought by the change of chemical composition, mechanical performance, geometric shape etc.  For nuclear fuel ： grasp the thermal-mechanical and chemical mechanism ； understand the behavior of fuel, cladding and matrix in the circumstance under different physical condition etc.

Requirements of irradiation test of NPP in operation Power tilt risingSteady Reactivity insertion accident Loss of flow accident Irradiation study of water chemistry Fission gas release requirements

Steady Two steps:  Carry out the irradiation test on the test reactor with fuel pellets, slug elements and small assemblies.  make the trial operation in power reactor with lead test assemblies (LTA).  gradually increase the burn-up of assemblies.

Power tilt rising Safety criteria:  Pellet Clad Interaction (PCI) Condition:  A certain speed of power tilt rising and final power should be reached Result:  final power can reach 2-3 times the rated power.

Reactivity insertion accident Purpose: determine a safe range. Within this range, under no circumstances will the fuel damage and fuel diffusion occur, so the cooling function of fuel elements can be maintained (not reach the critical heat flux).

Loss of flow accident Conditions:  Total oxidation calculated value of cladding: less than 17% of the original thickness.  Assuming a certain amount of fuel elements damage occurs, but maintains the in-core function and keeps the geometric shape of fuel rod and without fracture.  Single factor test.

FGR under steady, power tilt rising and accident condition Purpose of parameter test:  Determine the mechanism of FGR (Fission gas release ).  Evaluate the impact of the design parameter and irradiation parameter on FGR.  Verify and quantify the model and computer programme built through test.  Quantitatively give the source term in safety analysis. α hot chamber are required pay attention

Irradiation study of water chemistry Water chemistry in reactor is an outstanding study area. Significance:  relates to reactor safety, irradiation, and the consequent economy.  The reliability of the most systems of NPP depends on it.  undesirable effects (corrosion, erosion, oxidation, and the corrosion products on the surface of heat transfer etc. )

Irradiation test of New NPP fuel elements Works during the improvement of fuel elements performance: 1 Fuel improvement. 2 Improvement of fuel cladding. 3 Deepen burn- up and decrease the failure rate of fuel rod. 4 fuel enrichment : breaking the limits of 5%

Fuel improvement UO 2 adopts big crystal grain, optimizing shape and microstructure; MOX fuel with different Pu content; UO 2 fuel contained different burnable poison （ Gd 2 O 3 ， Er 2 O 3, ZrB 2 etc. ）

Improvement of cladding fuel Optimizing N 18, ZIRLO, ZrB 2 etc. Accumulating the data of various burn up level; Control MDA alloy and NDA alloy cladding texture to decrease PCI effect etc.

Deepen burn-up and decrease the failure rate of fuel rod. burn-up: verify the ability of reaching 100 GWd/tU; failure rate of fuel rod: study the problems related to decrease failure rate, and achieve the aim of “no failure”.

Irradiation test of New NPP structure material Studies carried out:  control rod assembly structural style;  cladding material and guide tube etc.  TiO 2 -Dy 2 O 3 is used as a new neutron absorber material.

Conclusion The experience of NPP shows that high reliability of NPP contributes to the achievement of test reactor in the past 50 years. With the design, construction, operation of NPP, the localization of nuclear power, the owners, operators and engineers will urgently demand the strong support from test reactor.

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