Recent modifications of a TRIGA reactor for NAA and other applications
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Recent modifications of a TRIGA reactor for NAA and other applications Sebastjan Rupnik1 · Borut Smodiš1 · Anže Jazbec1 Received: 3 February 2020 © Akadémiai Kiadó, Budapest, Hungary 2020
Abstract TRIGA type research reactors, even relatively new ones, are originally equipped with rather obsolete irradiation pneumatic transfer systems. Therefore, the irradiation system of Slovenian TRIGA Mark II system was renewed in 2015 to improve the overall quality of irradiations. This year, the system was upgraded to allow for automated short irradiations under more thermalized neutron flux. The modernization includes also a so-called “triangular” channel, allowing for in-core irradiation of samples up to 5 cm in diameter and a horizontal channel allowing for irradiations of objects under homogeneous neutron flux in the length of over 60 cm. Keywords TRIGA · Irradiation facility · Neutron activation analysis · Pneumatic transfer system · Large sample irradiation
Introduction Research reactors require frequent modifications of their experimental devices in reply to diverse and constantly changing customers’ needs. New projects are coming, new ideas are emerging and requests for non-typical irradiations are growing. Consequently, several modifications of irradiation facilities of the Jožef Stefan Institute (JSI) TRIGA Mark II reactor has recently been implemented [1]. In the following chapters, some of the latest reactor modifications are presented and discussed. A 2015 upgrade of the Standard pneumatic transfer system (STPS) had served as a base for subsequent upgrade of the Carousel pneumatic transfer system (CPTS), which is even more important from the perspective of applying neutron activation analysis (NAA). Request for irradiation of larger samples in the past had led to the modification of the horizontal beam port number 6. Some years later, a new project required irradiation of relatively large components in homogeneous flux, bringing about modification of another beam port, this time the horizontal beam port number 5.
* Borut Smodiš borut.smodis@ijs.si 1
Reactor Infrastructure Centre, Jožef Stefan Institute, Jamova cesta 39, 1000 Ljubljana, Slovenia
Last modification presented is the modification of the so-called “triangular” channel. The triangular channel was introduced about 20 years ago, when the first project requiring larger irradiation volumes than available at that time, was introduced. That modification was aimed at maximising the available space inside the reactor core with a newly shaped channel.
Pneumatic transfer system upgrade TRIGA research reactors are originally equipped with for today’s standards outdated pneumatic transfer systems and so was the JSI TRIGA Mark II reactor. The Standard pneumatic transfer system (SPTS), as it is called, was of very basic design. It consisted of a receiver assembly, tubing, a blower and valve assembly, and a simple control unit with a 5-min countdown clock. An analyst had to do everything manually and the only final station was located in the reactor basement,
