Nuclear Engineering and Design 187 (1999) 241 – 254
Experimental study on in-vessel debris coolability in
ALPHA program
Yu Maruyama *, Norihiro Yamano, Kiyofumi Moriyama, Hyun Sun Park,
Tamotsu Kudo, Yanhua Yang, Jun Sugimoto
Seere Accident Research Laboratory, Department of Reactor Safety Research, Japan Atomic Energy Research Institute,
2 – 4 Shirane, Shirakata, Tokai -mura, Naka -gun, Ibaraki -ken 319 -1195, Japan
Received 25 November 1997; received in revised form 23 July 1998; accepted 17 August 1998
Abstract
In-vessel debris coolability experiments were performed in ALPHA program at JAERI. Aluminum oxide (Al
2
O
3
)
produced by a thermite reaction was used as a debris simulant. Approximately 30 and 50 kg of Al
2
O
3
were poured
into a pool of nearly saturated water at the ambient pressure of approximately 1.3 MPa formed in a lower head
experimental vessel. The post-test visual observation and measurement using an ultrasonic technique indicated the
formation of a thin porous layer at the vicinity of the surface of the solidified Al
2
O
3
and the interfacial gap between
the solidified Al
2
O
3
and the lower head experimental vessel wall. Thermal transient characteristics on the lower head
experimental vessel wall observed in the experiments implied that the interfacial gap and the thin porous layer in the
solidified Al
2
O
3
layer acted as a thermal resistance during the initial heat-up stage, and water subsequently penetrated
into the interfacial gap to effectively cool the lower head experimental vessel wall. The maximum heat flux removed
from the experimental vessel was ranged from approximately 190 to 360 kW m
-2
while the temperature of the vessel
wall decreased rapidly. © 1999 Published by Elsevier Science S.A. All rights reserved.
Dedication to the memory of Norihiro Yamano. One of authors of the present paper, Norihiro Yamano, met with an untimely
death at the age of 42 on October 3, 1997. Since he entered JAERI in 1984, he actively made research progress in the field of a severe
accident. From 1988 he initiated and led JAERI’s large scale experiments, ALPHA program, aiming at several behaviors in a reactor
containment vessel. This paper is dedicated to the memory of Norihiro Yamano, because the in-vessel debris coolability experiments
in ALPHA program have been directed with his deep knowledge, broad experience and great leadership. An important part of
Yamano’s legacy will be the example of technical experience, productivity, cheerful character, open mind, kindness and personal
integrity that he set for all who worked with him. May his soul be in peace.
* Corresponding author. Tel.: +81-29-2825854; fax: +81-29-2825570; e-mail: maruyama@sun2sarl.tokai jaeri.go jp.
0029-5493/99/$ - see front matter © 1999 Published by Elsevier Science S.A. All rights reserved.
PII:S0029-5493(98)00278-7