Application and prospect of 85Kr starter in lighting field

Li Daming, Lihan Jun, Chen Qing Wang, Jia Tiejun, followed by gold, Zhang Haibo
(China Institute of Atomic Energy, Beijing 102413)
Abstract high intensity discharge lamp (HID) and a trace amount of the filling device 85 Kr can improve the starting performance of the product, to improve lumen maintenance of the lamp and prolong life. The filling amount of 85 Kr should meet the exemption value in GB18871-2002.

Keywords HID lamp metal halide lamp 85 Kr start

0 , preface

Metal halide lamps have become the green energy-saving electric light source of choice for all industries in the national economy due to their high luminous efficiency, good color rendering, long life and wide application range. China's production in 2005 was 25 million, making it the world's largest producer of metal halide lamps. But metal halide lamp difficult to start, especially the low-power 150W metal halide lamp difficult to start seriously restricted the production of high-end metal halide lamps. 20 years scientists from various countries to solve the rapid start metal halide lamp made a lot of research work, implemented a number of programs, received a certain effect, but does not solve the problem of instant start lamp fundamentally.

At the 8th International Symposium on Electric Light Source Technology held in August 1998, SAMucklejohn of GE Company of the United States first proposed the concept of “ 85 Kr-starter” for the development of 150W ceramic metal halide lamp, which is very effective. After 2000, world-renowned multinational companies such as Philips, American GE, Venture, OSRAM, and NGK of Japan have successively developed metal halide lamps with a minimum of 85 Kr. China's lighting companies have also been mass-produced with metal halide lamps filled with a trace amount of 85 Kr since 2004. Practice has proved that the lamp is filled with a trace amount of 85 Kr, the starting performance of the lamp is obviously improved, and the quality of the lamp is improved. China has taken a big step on the road of producing a strong country in the production of metal halide lamps.

1 , 85 Kr nature, filling amount and filling method

1.1 85 Kr's basic nature and source

Kr has a very small amount in nature, with an atmospheric content of 1 ppm and a sea level concentration of 1.14 ml/m 3 . So far, it has been confirmed that Kr has 25 isotopes, of which 6 are naturally occurring, but the most practical. The nuclides are 85 Kr. There is no 85 Kr in nature, 85 Kr is produced by nuclear explosion and 235 U fission in the reactor, and the fission yield is 0.228%.

Product 85 Kr is obtained through a series of physical and chemical processes such as capture, concentration, separation, purification and enrichment during nuclear fuel reprocessing. For example, the United States Idaho Post Treatment Plant collected 43000Ci of 85 Kr in 1974, concentrated. The multiple is 10 4 and the recovery rate is 97%. The 100% enrichment of 85 Kr has a specific activity of 393 Ci/g.

85 Kr is a beta - decay type of radionuclide with a half-life of 10.77 years.

The decay profile of 85 Kr is:

1.1 85Kr filling amount

The 85Kr activity filled into the lamp and the device is determined by many factors such as the geometry, shape, structure, power of the arc tube, and the inflation pressure specified by the process. The filling activity should meet the exemption value of GB18871-2002 (<104Bq/piece). ).

In general, low-power lamps are more difficult to start than medium-high-power lamps, so the 85Kr filled in the low-power arc tube is high. The single-electrode OSRAM, Philips, and UPS arc tubes are charged at 85Kr higher than the US Venture arc tube with auxiliary poles. Referring to the activity value of 85Kr in the lamp of several famous electric light source companies abroad, 85Kr (0.02μCi-0.2μCi) filled with several hundred to several thousand Becker in each lamp is enough to significantly improve the starting performance of the metal halide lamp.

1.2 85Kr starter filling method

The filling of 85Kr starter is not much different from the traditional filled inert gas. However, the circulating gas used now contains 85Kr of trace radioactive gas, which requires a slight improvement on the equipment. The first purpose is to improve the utilization rate of the starter and reduce the cost. The second is to minimize the pollution of the environment.