View source for RV Mirai

{|{{Infobox ship begin <!-- full code -->
|infobox caption= <!-- keywords: yes, nodab; or caption text -->
|display title= <!-- keywords: none, ital; or article title with markup -->
}}
{{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<ref name="seaweb">{{csr|register=SEAWEB|id=6919423|shipname=Mirai|accessdate=18 August 2019}}</ref>
|Ship builder=[[IHI Corporation|Ishikawajima-Harima Heavy Industries]], [[Tokyo]], Japan<ref name="seaweb" />
|Ship original cost=
|Ship yard number=2107<ref name="seaweb" />
|Ship laid down=27 November 1968<ref name="seaweb" />
|Ship launched=12 June 1969<ref name="seaweb" />
|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 language|Japanese]] for "future"
|Ship owner=[[Japan Agency for Marine-Earth Science and Technology]]<ref name="equasis" />
|Ship registry=
|Ship builder=[[Mitsubishi Heavy Industries]], [[Shimonoseki]], Japan (new stern section)<ref name="seaweb" />
|Ship original cost=
|Ship laid down=
|Ship launched=
|Ship sponsor=
|Ship christened=
|Ship completed=1 October 1997<ref name="seaweb" />
|Ship in service=
|Ship identification=* {{IMO number|6919423}}
*{{MMSI|431939000}}
*[[Maritime call sign|Call sign]]: JNSR<ref name="equasis">{{csr|register=E|id=6919423|shipname=Mirai|accessdate=18 August 2019}}</ref>
|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 [[pressurized water reactor|PWR]] ([[low-enriched uranium|LEU]] <= 4.44%<ref>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}}</ref>)
|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'')<ref name="seaweb" /><ref name="Jamstec2007">{{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}}</ref>
|Ship type=[[Research vessel]]
|Ship tonnage=* {{GT|8706}}
* {{NetT|3419}}
|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
* [[Controllable pitch propeller]]s
|Ship speed=* {{convert|18.3|kn}} (maximum)
* {{convert|16|kn}} (service)
|Ship range={{convert|12000|nmi}}
|Ship endurance=
|Ship boats=
|Ship capacity=
|Ship crew=* 34 crew
* 46 research personnel
|Ship aircraft=
|Ship aircraft facilities=
|Ship notes=
}}
|}

'''RV ''Mirai''''' is a Japanese [[oceanography|oceanographic]] [[research vessel]]. She was originally built as the [[nuclear marine propulsion|nuclear-powered]] general cargo ship '''''{{ill|Mutsu (nuclear ship)|jp|むつ (原子力船)|lt=Mutsu}}''''',<ref name="OECD">{{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}}</ref> but never carried commercial cargo.<ref name="autogenerated1">http://www.iaea.org/inis/collection/NCLCollectionStore/_Public/27/029/27029493.pdf {{Bare URL PDF|date=March 2022}}</ref>

== 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.<ref name="Nakao">{{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.</ref> When officials announced that the first test run was to be run at the pier in [[Mutsu, Aomori|Ōminato]], local protests forced them to reconsider.<ref name="Nakao"/> Eventually it was decided to test the ship in the open ocean, {{convert|800|km|nmi}} east of [[Higashidōri, Aomori|Cape Shiriya]].<ref name="Nakao"/> The ship departed Ōminato on 26 August 1974, and the reactor attained criticality on 28 August.<ref name="Nakao"/>

====Radiation accident====
As the crew brought the reactor up to 1.4% of capacity at 5pm on 1 September 1974,<ref name="Nakao"/> there was a minor shielding inadequacy that permitted the escape of neutrons and gamma rays<ref name="OECD"/> from the reactor shielding enclosure.<ref name="Nakao"/> [[Westinghouse Electric Corporation]] had reviewed the design and warned of this possibility, but no changes were made to the design.<ref name="Nakao"/> There was no significant radiation exposure, but it became a political issue, with local fisherman blocking her return to port for more than 50 days.<ref name="OECD"/> 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.<ref name="Nakao"/>

In [[Sasebo, Nagasaki|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.<ref name="Nakao"/> Following an overhaul, the ''Mutsu'' was completed in February 1991.<ref name="Nakao"/> She then completed her original design objective of travelling {{convert|82000|km|mi}} in testing, and was decommissioned in 1992.<ref name="Nakao"/> Over 25 years the programme had cost more than 120 billion yen (about US$1.2 billion).<ref name="Nakao"/>

=== ''Mirai'' (1996–present) ===

After removing the reactor in 1995 and decontaminating the vessel, ''Mutsu'' was rebuilt as the ocean observation vessel ''Mirai''.<ref name="OECD"/><ref>{{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}}</ref>

== 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}}.<ref>{{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}}</ref>  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.<ref name="autogenerated1"/>

== See also ==
* [[NS Savannah|''Savannah'']], the world's first nuclear-powered cargo ship
* [[Otto Hahn (ship)|''Otto Hahn'']], a German nuclear-powered cargo ship
* ''[[Sevmorput]]'', a Soviet and later Russian nuclear-powered cargo ship

== 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]]
[[Category:1969 ships]]
[[Category:Ships built by IHI Corporation]]