HTGR Knowledge Base

Conference Article: Characteristics of DC electrical braking method of the gas circulator to limit the temperature rise at the heat transfer pipes in the HTTR

K. KAWASAKI, K. SAITO and T. IYOKU(JAERI, Department of HTTR Project, Japan)

Abstract

In the safety evaluation of a High Temperature Engineering Test Reactor (HTTR), it must be confirmed that the core has no chance to he damaged and the barrier against the FP release is designed properly not to be affecting the influence of radiation around the reactor site. Especially, the maximum temperature of the reactor pressure boundary such as the heat transfer pipes of pressurized water cooler (PWC) must not exceed the permissible values under an anticipated accident such as pipe of rupture in PWC.

A requirement for the gas circulator which circulate helium gas in the primary cooling line and the secondary cooling line is to he braked within 10 second by an electrical braking method after the HTTR reactor has scrammed under the accident in PWC. The reason is why the temperature rise of the heat transfer pipe at PWC has to he suppressed when the gas circulator has stopped, the revolution of the gas circulator is decreases like the free coast down that it takes about 90 second to be zero and the temperature rise of the pipe in the PWC exceeds the permissible value.

By braking within 10 sec, the temperature of the pipe in the PWC is reached about 368 deg. C that is less than the permissible value. Using a simplified equivalent circuit of an induction motor, braking, time analysis was performed with obtained electrical resistance and inductance. The obtained braking time is about 10 sec that shows close agreement with analysis values.

view the full text of this article (13 pages, format: PDF, size= 574kB)

key words: Gas Cooled Reactor, Nuclear Technology
Reference:
Proceedings of a Technical Committee Meeting held in Beijing, People's Republic of China, 2-4 November 1998
International Atomic Energy Agency, International Working Group on Gas-Cooled Reactors, Vienna (Austria)
IAEA-TECDOC--1210, pp:167-179