The Nikkei stock index briefly sank 3 percent Thursday morning, as tech shares tracked plunges of their counterparts on Wall Street and exporters were hit by the yen’s surge to the 152 range against the U.S. dollar. The 225-issue Nikkei Stock Average fell 989.66 points, or 2.53 percent, from Wednesday to 38,165.19 in the morning session. The broader Topix index was down 60.29 points, or 2.16 percent, at 2,732.83. The dollar briefly fell by over 1 yen to the mid-152 yen range in Tokyo, its lowest level since early May, as the Japanese currency was bought amid rising speculation that the Bank of…