RV Mirai
| {{Infobox ship begin
|infobox caption= |display title= }} {{Infobox ship image |Ship image=File:RV Mirai (2007-12-27).jpg |Ship image size= |Ship caption=Mirai on 27 December 2007 }} {{Infobox ship career |Hide header= |Ship country=Japan |Ship flag={{shipboxflag|Japan}} |Ship name=Mutsu |Ship namesake=Mutsu, Aomori |Ship owner= |Ship operator= |Ship registry= |Ship route= |Ship ordered=17 November 1967{{csr|register=SEAWEB|id=6919423|shipname=Mirai|accessdate=18 August 2019}} |Ship builder=Ishikawajima-Harima Heavy Industries, Tokyo, Japan |Ship original cost= |Ship laid down=27 November 1968 |Ship sponsor= |Ship completed=4 September 1972 (fuel loaded) |Ship decommissioned=1992 |Ship maiden voyage= |Ship in service= |Ship fate=Rebuilt as the research vessel Mirai }} {{Infobox ship career |Hide header=title |Ship country=Japan |Ship flag={{shipboxflag|Japan}} |Ship name=Mirai |Ship namesake=Japanese for "future" |Ship owner=Japan Agency for Marine-Earth Science and Technology |Ship registry= |Ship builder=Mitsubishi Heavy Industries, Shimonoseki, Japan (new stern section) |Ship original cost= |Ship laid down= |Ship launched= |Ship sponsor= |Ship christened= |Ship completed=1 October 1997 |Ship in service= |Ship identification=* {{IMO number|6919423}}
|Ship status=In service |Ship notes= }} {{Infobox ship characteristics |Hide header= |Header caption=(as Mutsu) |Ship type=General cargo ship |Ship tonnage= |Ship displacement= |Ship length={{convert|130|m|ft|0|abbr=on}} |Ship beam={{convert|19|m|ft|0|abbr=on}} |Ship height= |Ship draught={{convert|6.9|m|ft|0|abbr=on}} |Ship depth={{convert|13.2|m|ft|0|abbr=on}} |Ship ice class= |Ship power=36-megawatt Mitsubishi PWR (LEU <= 4.44%https://lynceans.org/wp-content/uploads/2018/07/Marine-Nuclear-Power-1939-2018_Part-5_China-India-Japan-Others.pdf {{Bare URL PDF|date=March 2022}}) |Ship propulsion=Steam turbine, 10,000{{nbsp}}shp |Ship speed={{convert|17|kn}} |Ship range= |Ship endurance= |Ship boats= |Ship capacity= |Ship crew=80 |Ship notes= }} {{Infobox ship characteristics |Hide header= |Header caption=(as Mirai){{cite web|url=http://www.jamstec.go.jp/e/about/equipment/ships/mirai.html|title=Oceanographic research vessel Mirai|publisher=Japan Agency for Marine-Earth Science and Technology|archiveurl=https://web.archive.org/web/20090420013359/http://www.jamstec.go.jp/e/about/equipment/ships/mirai.html|archivedate = 2009-04-20|url-status=dead}} |Ship type=Research vessel |Ship tonnage=* {{GT|8706}}
|Ship displacement= |Ship length={{convert|128.5|m|ft|0|abbr=on}} |Ship beam={{convert|19|m|ft|0|abbr=on}} |Ship height= |Ship draught={{convert|6.9|m|ft|0|abbr=on}} |Ship depth={{convert|10.5|m|ft|0|abbr=on}} |Ship ice class=1A |Ship power=4{{nbsp}}×{{nbsp}}Daihatsu 6DKM-28 (4{{nbsp}}×{{nbsp}}1,838{{nbsp}}kW) |Ship propulsion=* Diesel-electric, two shafts |Ship speed=* {{convert|18.3|kn}} (maximum)
|Ship range={{convert|12000|nmi}} |Ship endurance= |Ship boats= |Ship capacity= |Ship crew=* 34 crew
|Ship aircraft= |Ship aircraft facilities= |Ship notes= }} |
RV Mirai is a Japanese oceanographic research vessel. She was originally built as the nuclear-powered general cargo ship {{ill|Mutsu (nuclear ship)|jp|むつ (原子力船)|lt=Mutsu}},{{citation |last=OECD Nuclear Energy Agency |title=Investing in Trust: Nuclear Regulators and the Public : Workshop Proceedings, Paris, France, 29 November - 1 December 2000 |url= https://books.google.com/books?id=zntOXdbpLiEC&q=mutsu&pg=PA30 |page=30 |year=2001 |publisher=OECD Publishing |isbn=978-92-64-19314-7}} but never carried commercial cargo.http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/27/029/27029493.pdf {{Bare URL PDF|date=March 2022}}
History
= Development and construction =
{{expand section|date=August 2019}}
= ''Mutsu'' (1972–1996) =
The reactor was completed on 25 August 1972, and fuel was loaded on 4 September.{{citation |last=Nakao |first=Masayuki |title=Radiation Leaks from Nuclear Power Ship "Mutsu" |url=http://shippai.jst.go.jp/en/Detail?fn=2&id=CA1000615 |format=PDF |publisher=Japan Science and Technology Agency (JST) }}{{dead link|date=December 2017 |bot=InternetArchiveBot |fix-attempted=yes }} Good overview of the construction, leak, and lessons learnt. When officials announced that the first test run was to be run at the pier in Ōminato, local protests forced them to reconsider. Eventually it was decided to test the ship in the open ocean, {{convert|800|km|nmi}} east of Cape Shiriya. The ship departed Ōminato on 26 August 1974, and the reactor attained criticality on 28 August.
==Radiation accident==
As the crew brought the reactor up to 1.4% of capacity at 5pm on 1 September 1974, there was a minor shielding inadequacy that permitted the escape of neutrons and gamma rays from the reactor shielding enclosure. Westinghouse Electric Corporation had reviewed the design and warned of this possibility, but no changes were made to the design. There was no significant radiation exposure, but it became a political issue, with local fishermen blocking her return to port for more than 50 days. The government finally came to an agreement with the local government and fishermen; the Mutsu was allowed back to port on condition that it was to find a new home port, and the ship returned to Ōminato on 15 October.
In Sasebo, between 1978 and 1982, various modifications were made to the reactor shield of the Mutsu, and its home port was moved to Sekinehama in 1983. Following an overhaul, the Mutsu was completed in February 1991. She then completed her original design objective of travelling {{convert|82000|km|mi}} in testing, and was decommissioned in 1992. Over 25 years the programme had cost more than 120 billion yen (about US$1.2 billion).
= ''Mirai'' (1996–present) =
After removing the reactor in 1995 and decontaminating the vessel, Mutsu was rebuilt as the ocean observation vessel Mirai.{{cite web|url=http://www.jamstec.go.jp/e/about/equipment/ships/mirai.html |title=MIRAI < Research Vessels and Vehicles < Research Vessels, Facilities and Equipment < About JAMSTEC < JAMSTEC |publisher=Jamstec.go.jp |date= |accessdate=2016-07-17}}
Mutsu Science Museum
The reactor room, control room, bridge, bow, and propeller were converted into a museum and are open to the public at the {{ill|Mutsu Science Museum|jp|むつ科学技術館}}.{{cite web|url=http://www.jmsfmml.or.jp/msm.htm |title=むつ科学技術館のホームページへようこそ！！ |publisher=Jmsfmml.or.jp |date= |accessdate=2016-07-17}} Visitors can interact with the controls in the control room and view the reactor vessel through several viewing ports.
The nuclear material from the ship is stored across the street from the museum at a facility operated by the Japan Atomic Energy Agency.
See also
References
{{Reflist}}
{{Japan Agency for Marine-Earth Science and Technology vessels and vehicles}}
{{Nuclear-powered civilian ships}}
{{Nuclear power in Japan}}
{{Nuclear surface ships}}
{{DEFAULTSORT:Mirai}}
Category:Research vessels of Japan
Category:Japan Agency for Marine-Earth Science and Technology