TOKYO, April 16 (Reuters) - Japan's Nikkei share average fell 1.2 percent at the open on Monday on renewed concerns about Europe's debt crisis after rising bond yields in Spain and a record-high cost of insuring the country's debt against default spooked investors. The benchmark Nikkei lost 109.71 points to 9,528.63 after two previous sessions of gains, while the broader Topix fell 1 percent to 807.74.