LNG transport vessel Eduard Toll transiting the Northern Sea route without icebreaker escort, December/January 2017/18
gCaptain provides proof we can expect to see merchant vessel transits of the Arctic Ocean even in Winter time.
“At times during the trip, the unescorted Eduard Toll broke ice 1.8 meters thick at speeds of five knots astern, arriving at Sabetta ahead of schedule sometime in early January. “
The Eduard Toll is one of a class of six being built in S. Korea for a Russian/Chinese joint venture.
Chuck Hill's CG Blog 
The reason that Eduard Toll doesn’t need Icebreaking Assistance, is because she was designed to be the World’s First Purpose Built LNG Carrier/Icebreaker.
First of a class of six, but I expect we will be seeing more similar ships.
There’s three or four of these ships in operation and 15 will be built in total for different companies.