Technical Tour A includes a visit to the Horonobe Underground Research Laboratory (URL) of the Japan Atomic Energy Agency (JAEA*). JAEA has been carrying out research and development on the geological disposal of high-level radioactive waste to verify the technical reliability of such geological disposal through testing and research conducted in an actual deep geological environment in the Horonobe URL, which is located at the northernmost tip of Hokkaido. Excavations of the galleries at a depth of 350 m and the access shafts at a depth of 380 m have been completed (Fig. 2). In the galleries and shafts, various in situ surveys have been conducted in order to understand the geological environment of the deep underground. Also, the applicability of geological disposal technology has been studied through these surveys. The return trip from Horonobe will include a visit to a road tunnel disposal site and observation of the facilities for heavy metal-rich muck.

(*: The independent administrative agency）

Fig.1 Aerial photograph of the Horonobe Underground Research Laboratory.
Photo courtesy of Japan Atomic Energy Agency.

Fig.2 Layout of the Horonobe Underground Research Laboratory, shaft and gallery.
Photo courtesy of Japan Atomic Energy Agency.

Kyogoku Power Station is the first pure pumped-storage hydroelectric plant in Hokkaido. It is located in the northern area of Kyogoku Town, Abuta County. The upper regulating reservoir (rockfill dam with asphalt facing) was constructed on a comparatively gentle plateau at an elevation of about 900 m, and Kyogoku Dam (rockfill dam with vertical clay core) was constructed as a lower regulating reservoir in the confluence of the Pehpenai River and the Bibinai River in the Shiribetsu River (class A river) system.

These reservoirs are connected by an approximately 3-km tailrace tunnel. The gross head of 369 m and the 190.5 m3/sec of water will be used to generate electric power of 600 MW (maximum) and to pump it into the underground power station, which has 430 m of overburden and three turbine generators.

Otaru will be visited on the return trip. Otaru is a tourist resort representing Hokkaido and is famous for its canal, glassworks and seafood, etc.

The upper regulating reservoir.
Photo courtesy of Hokkaido Electric Power Co., Inc.

Kyogoku Dam (the lower regulating reservoir).
Photo courtesy of Hokkaido Electric Power Co., Inc.

Underground power station.
Photo courtesy of Hokkaido Electric Power Co., Inc.

The Hokkaido Transverse Expressway (Kuromatsunai-Kushiro line) is a 538-km long expressway which crosses Hokkaido from east to west. The East Nippon Expressway Company Limited (NEXCO-East) has been constructing a 23.5-km stretch of the expressway between Yoichi and Otaru.

Many bridges and tunnels are planned for this stretch because it is located in a mountainous region. The total length of the 7 tunnels and 12 bridges accounts for almost half of the stretch.

A visit to three construction working sites is planned for this tour as follows:

• The Second Tenjin Tunnel work: The second Tenjin Tunnel (2,829 m, under pumice-tuff and volcaniclastic rock) passes through Mt. Kenashi (548.2 m) near Otaru.
• The Asarigawa Bridge substructure work: The Asarigawa Bridge (615.5 m) crosses four roads and two rivers. The work includes the construction of 2 abutments and 7 piers.
• The Yoichi construction work: This work includes the construction of Yoichi Interchange and the main line. The work consists of 280,000 m3 of earthworks, substructure works of the Fugoppe River Bridge, and other minor works. In addition, as buried cultural properties were found in this area, Yoichi Town has been conducting excavation research.

This tour also includes visits to popular tourist spots: the Nikka Whisky Distilling Factory in Yoichi and Otaru Canal.

The visits to the Nikka Whisky Distilling factory in Yoichi and the canal in Otaru are also included in this tour.

The second Tenjin Tunnel.
Photo courtesy of the East Nippon Expressway Company.

Asarigawa Bridge.
Photo courtesy of the East Nippon Expressway Company.

Yoichi construction site.
Photo courtesy of the East Nippon Expressway Company.

Archeological excavation site at Yoichi construction site.
Photo courtesy of the East Nippon Expressway Company.