1. THE FUKUSHIMA NUCLEAR ACCIDENT ON THE TECHNOLOGY DEVELOPMENT OF NEW NUCLEAR POWER PLANTS 1.IRSHAD NURHAKIM BIN NORAHIM (ME088151) 2.LEE SZE TENG (ME087909) 3.CHRISTOPHER TSEU ZIA CHYUAN (ME088609) 4.MOHD RAHIMI AFIF BIN MOHD RAZALI (ME087931) 5.MOHD FARHAN BIN ISMAIL (ME087927)

2. INTRODUCTION OF NUCLEAR POWER PLANT REACTOR Use of exothermic nuclear processes to generate useful heat and electricity, which includes nuclear fission, nuclear decay and nuclear fusion. However, the economic costs of nuclear power accidents is high, and meltdowns can render areas uninhabitable for very long periods. The human costs of evacuations of affected populations and lost livelihoods is also significant. Low carbon power generation method of producing electricity with an analysis of the literature on its total life cycle emission intensity.

3. Fukushima Daiichi Nuclear Disaster, which occurred in a reactor design from the 1960s, prompted a re-examination of nuclear safety and nuclear energy policy in many countries. The plant consists of six Boiling Water Reactor (BWR). These light water reactor drove electrical generators with a combined power of 4.7 GWe, making Fukushima Daiichi one of the 15 largest nuclear power station in the world. The plant suffered major damaged from the magnitude 9.0 earthquake and tsunami that hit Japan on March 11, 2011.

4. There was evidence of partial nuclear meltdown in units 1, 2 and 3 which are visible explosions. Units 1, 2 and 3 have been rated at Level 5 each on the International Nuclear Event Scale. At unit 4 as Level 3 (Serious Incident) events. The overall plant rating at Level 7 (major release of radioactive material with widespread health and environmental effects r­ equiring implementation of planned and extended countermeasures).

5. IMPACT OF NUCLEAR POWER PLANT REACTOR After Fukushima nuclear accident, there are change on the technology development for new design light water reactor (LWR) nuclear power plant. The generation three plus with Passive Safety Design : 1.(Significant Improvement of Safety against loss of coolant accident LOCA). 2.Passive Safety Design is Passive nuclear safety is a safety feature of a nuclear reactor that does not require operator actions or electronic feedback in order to shut down safely in the event of a particular type of emergency. 3.Such reactors tend to rely more on the engineering of components such that their predicted behavior according to known laws of physics.

6. For example : Economic Simplified Boiling Water Reactor (ESBWR) 1.ESBWR is improvement from the Simplified Boiling Water Reactor (SBWR) and from the Advanced Boiling Water Reactor (ABWR). 2.This design from GE Hitachi Nuclear Energy (GEH). 3.The main objectives :  60 year plant life from the date of full power operating license.  92% or greater plant availability.  12-24 month refueling intervals.  Personnel radiation exposure limit of 50 man-rem/year.  Safety related functions primarily through passive means.  Core damage frequency of less than 10-6 per reactor year.  Significant release frequency from all events limited to 5 x 10 -8 per reactor year.  No operator action or AC power supply required for safety systems for 72 hours to maintain the reactor and containment at safe stable conditions.

7. Other design with passive safety design is AP 1000. 1.This design is to meet applicable safety requirements and goals defined for advanced light water pressurized water reactors with passive safety features. 2.The objective for the AP1000 :  provide a greatly simplified plant with respect to design, licensing, construction, operation, inspection and maintenance.  The core-cooling tank in the AP-1000 design has valves held shut by AC power.  This class of reactors, known as a called Generation III+, are also built to a standardized design, with most component modules pre-fabricated in a factory and then assembled on site.  These quality controls reduce cost but also enhance reliability and safety.

8. SAFETY OF NUCLEAR POWER PLANT REACTOR Control of radioactivity (diminish radioactivity).  The most widely recognized approach to diminish the neutron flux is incorporate neutron-retaining control bars. Maintenance of core cooling.  By and large atomic reactors use water as a coolant because it is more safety compared using sodium or sodium salts. Maintenance of barriers that prevent the release of radiation.  The design of the reactor also includes multiple back-up components, independent systems monitoring of instrumentation and the prevention of a failure of one type of equipment affecting any other.

9. Good design.  The overall concept has to be well thought out, and big decisions like secondary containment decided on.  Then it is a matter of working out all possible failure sequences, and showing that major accidents are reduced to a probability of less than 10-6 per annum. Construction.  Nuclear plant must built to the required specification, the correct materials used, and techniques such as welding must be fully inspected and recorded. Operation.  The operators must be well trained and supervised, and have the correct operating manuals, and have had training in what to do in unusual conditions

10. Fukushima Plant & Reactor Design 1.Passive Reactor Core Cooling Systems cool a reactor core without requiring AC electric power combinations of gravity, natural circulation, DC power and compressed gas to transfer heat to either evaporating water pools or to structures cooled by air or water convection

11. 1. Pressurized core flooding tanks (accumulators) already used in some currently operating reactors as part of their emergency core cooling systems. typically consist of large tanks about 75% full of cold borated water

12. Con’t contents of the tank are isolated from the reactor by check valves that are held shut during normal operation by higher pressure in the reactor. In the event of a Loss-of-Coolant Accident (LOCA), the reactor pressure will drop, opening the check valves and discharging the borated water into the reactor vessel. one-time discharge of cold water to buy time, prior to longer term emergency core cooling systems starting up. Accumulators do not provide continuing heat removal.

13. 2. Elevated tank circulation loops (core make-up tanks) bottom valve is opened to allow the cold borated water to flow into the loop cold borated water flows down into the core where it is heated, rises and flows back into the tank through the inflow line do not provide continuing heat removal.

14. 3. Elevated gravity drain tanks they are driven by gravity rather than pressurized gas effective when the pressure in the reactor core is not greater than the weight of the water in the tank ineffective if the core is uncovered and generating high pressure steam water in the tank is sufficiently large to flood the entire reactor cavity one-time discharge of water to buy time

15. 4. Passive containment spray systems a LOCA the steam in contact with the inside of the steel containment would condense. Heat would be transferred through the containment wall to the air outside the wall, which would rise as it is heated It would be discharged through the top of the structure and replaced by cooler air continually entering at the bottom. A pool on top of the containment would provide a gravity driven spray of cold water to accelerate the cooling if DC power is available This system is included in some new plants currently under construction.

16. Con’t

17.  Malaysia should adopt ABWR as the nuclear selection as : 1.It has fully digital I&C which adopted internal pump by eliminating large external recirculation coolant loop to avoid loss of coolant accident. 2.This improve its safety systems and reduce the core damage frequency to low values aside from that one of the containment vessel is made of reinforced concrete with steel liner to reduce off-site accidents. 3.With existing reactor capacity of 1370 MW, future technology advancement in ABWR and standardized design capable is expected uprates up to 1500 MW due to addition of existing reactor core margin. 4.This NPP is designed to run for 60 years of its overall life cycle which enhance the capital investment in the long term effort in generating electricity. 5.ABWR also requires less equipment, piping than compare to similar size PWR hence significantly lowers the cost needed for staffing and maintenance costs per kWh.

18. CONCLUSION  The selection of the most suitable design requires an objective assessment of both the technical and economic benefits of each design.  The associated technologies and related fuel cycle, all of which must be evaluated against the conditions and the needs of each country.