Technologies

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Ebara Engineering Review No.247

Development of Decomposition Method of Hydrogen Peroxide in Spent Fuel Pool

by Takeshi IZUMI, Makoto KOMATSU, Tatsuya DEGUCHI, Daisuke AKUTAGAWA, Takeshi MANABE, & Yusuke NAKANO

From the viewpoint of the minimizing the corrosion of the spent fuel rods and structural material in the spent fuel pool, the ion exchange resins are generally used as one of purification system in order to keep water quality clean.
Hydrogen peroxide generated by the radiolysis of water exists in the pool water and it accelerates the oxidation decomposition of the ion exchange resins and finally, it becomes the cause to shorten the resin life.
To solve this problem, the application of Pd doped resins which can decompose hydrogen peroxide catalytically at the surface has been considered. It was confirmed by the cold test that Pd doped resins overlaid on the ion exchange resins decomposed hydrogen peroxide contained in the pool water and inhibited the oxidative degradation of the ion exchange resins.
Based on the results, hot examination tests by using actual pool water in Tsuruga-2 were carried out from Jan. 2014 to Mar. 2014. We report the results of these tests.

Keywords
Pd doped resins, Hydrogen peroxide, Ion exchange resins, Spent fuel pool, Nuclear power plants

Improvement of Long-term, Continuous Operation of Stoker Type Incinerator Using Pin Bound Type Fire Grates

by Teruaki TSUKAMOTO

Energy reuse such as the ability to generate power has become increasingly important among the roles of municipal solid waste incineration facilities, besides their original purpose of sanitization. Additionally, their expected role has recently begun to include one as a base of operation in the event of a disaster. This has resulted in a further demand for incineration facilities to run stably and continuously on a long-term basis. Ebara Environmental Plant Co., Ltd. improved existing fire grates and stoker structure, and developed a pin bound type fire grate with higher mechanical stability and maintainability. The company further introduced this technology into a municipal solid waste incineration facility to conduct a continuous long-term stable operation test, verifying its effect. It thus successfully developed a new stoker furnace suitable to treat waste of various characteristics.

Keywords
Municipal solid waste, Incinerator, Stoker, Fire grate, Pin bound type

New Water Supply Pump for Household Use: Model HPE

by Kazumi OHKANDA, Takahide OZAWA, & Yasutaka KONISHI

A new variable speed type pump, model HPE, was launched in November 2014 as an integrated pump of model HPF (variable speed type) and model HPA (fixed speed type), which have been commercially available since 2004 and 2007 respectively, as a water supply pump for household use. This HPE model meets the recent market needs for energy saving and low noise operation in residential areas, combining a high-efficiency pump, a permanent magnet synchronous motor equivalent to IE4, and a controller and an inverter with efficient operation. In the 250 W model, compared to conventional models (model HPA), approximately 48% of energy saving and as low as 12 dB (A) of noise are achieved.

Keywords
Inverter, Permanent magnet synchronous motor, Constant pressure control, Energy saving, Low noise operation, External output, Lead-free, Shallow wells, Incombustible material, Compatibility

Introducing the Reverse Running Pump Turbine to Shumarinai Power Station

by Ryoji OOTAKE, Yuta NAGANO, & Takafumi KOGUCHI

We delivered the reverse running pump turbine with the 800 x 700 mm pump diameter and auxiliary machinery to Hokkaido Electric Power Co., Inc. Shumarinai Power Station, and performed installation and commissioning on site. The reverse running pump turbine is less expensive than the reversible pump-turbine, and has almost the same efficiency in terms of pumping and generating operations. To introduce the reverse running pump turbine, we conducted a model test with a miniature pump in advance to identify operation characteristics. We also decided on the equipment specifications and control methods based on the results of the hydraulic transient analysis. This facility adopts rotation speed control using inverters and converters in order to operate properly as conditions change on-site. The completion of this power station enables previously unutilized irrigation discharge water to be collected as electric energy.

Keywords
Reverse running pump turbine, Hydroelectric power station, Unutilized energy, Variable-speed operation, Frequency control, Model test, Hydraulic transient analysis

Water Supply Equipment: Introduction of Product Technologies
-Part 3: ON/OFF Control System-

by Kazutaka OKUDA

This series introduces technologies for EBARA water supply equipment that is our main product, and the types, uses and selection of water supply systems were explained in the previous two articles. This third article provides an introduction of the "ON/OFF control system,"which is the most basic pressure control system among water supply systems, and the water supply equipment controlled thereby. Control system details, the actual structure and main components, various special specifications, and protective functions for safe operation are illustrated.

Keywords
Water supply equipment, ON/OFF, Control system, Pump, Pressure tank, Inching, Pressure sensor, Special specifications, Flow switch, Protective function