JAPAN ATOMIC INDUSTRIAL FORUM, INC.

for Japanese

ATOMS in JAPAN

30 May, 2017

Submersible Crawling Robot to Examine Interior of Fukushima Daiichi-3 PCV before Fuel Debris Is Removed

On May 25, the Tokyo Electric Power Co. (TEPCO) released a status report on the ongoing decommissioning work at the Fukushima Daiichi Nuclear Power Plants, which suffered a tsunami-caused meltdown in March 2011.

The submersible robot

Starting two months ago, in March, a self-propelled robot has been used to investigate the interior of the primary containment vessel (PCV) of Unit 1 at Fukushima Daiichi—a necessary step before fuel debris can be removed. As of April 6, the robot had sampled deposits twice.

Fluorescent X-ray spectroscopy has now confirmed the presence of elements that had originally existed in the PCV, such as iron and nickel within the reactor core internals, stainless steel in the heat-insulating materials, zinc in the paint, and lead in the shielding materials.

Although uranium was confirmed as the primary radioactive nuclide within Unit 1, it is not necessarily part of the fuel debris there, given that that element exists naturally. TEPCO said that it would carry out more detailed analyses to confirm the uranium’s source.

As the water level in the PCV of Unit 3 is higher than that in Units 1 and 2, its so-called “X-6 penetration”—which would give easier access to the inside of the pedestal (under the reactor pressure vessel)—is submerged. TEPCO plans to investigate the interior of that unit’s PCV at an undetermined date this summer using a submersible robot that can both crawl and swim. Earlier this month, the power utility began taking measurements using muon observation technology to determine the location of fuel debris.

Under the “Mid-and-Long-Term Roadmap” toward decommissioning, TEPCO will determine policies on fuel debris removal at each Fukushima Daiichi unit this summer. According to its May 22 report to an expert panel of the Nuclear Regulation Authority (NRA), the power company has already made investigations to determine general conditions inside the individual PCVs.

TEPCO will continue to focus on gathering information during the current fiscal year (ended March 31, 2018), including that on the forms and distribution of fuel debris—necessary to determine the means to remove it—and safety measures for the actual removal work.

Comment

SNS facebooktwitter

NPPs Map

Video

“The current situation at Fukushima Daiichi NPS” -From 3.11 toward the future- (ver, Jan. 2018)

15 January, 2018
“The current situation at Fukushima Daiichi NPS” -From 3.11 toward the future- (ver, Jan. 2018)08:23

Recent News

15 January, 2018
ANRE Head Meets Niigata Governor on Kashiwazaki Kariwa, Delivers Document from METI Minister
11 January, 2018
JAIF Chairman Imai Calls Upon Domestic Nuclear Industry to Strengthen Cooperation Through Concerted Efforts
5 January, 2018
Toshiba ESS, IRID Develop Device to Investigate Interior of Primary Containment Vessel at Fukushima Daiichi-2 NPP
27 December, 2017
Kashiwazaki Kariwa 6 & 7 Clear Safety Examinations, First BWRs
21 December, 2017
16 Teams Compete in Second Hairo Sozo Robot Contest in Naraha Town
12 December, 2017
JAEA Officially Classifies Monju Fast Reactor as “Closed Down”
12 December, 2017
Seven-point Contraction in Nuclear Share of Energy Mix Would Push Real GDP Down by 2.5 to 2.7 Trillion Yen
28 November, 2017
Fukui Governor Agrees to Restart Ohi-3 and Ohi-4 NPPs, with Local Procedures Complete
28 November, 2017
JAPC Files Application for Permission to Extend Lifetime of Tokai-2 NPP to 60 Years
13 November, 2017
EU to Lift Restrictions on Imports of Fukushima Products in December
▲TOP