THE World Bank is set to approve its first three loans to Vietnam in the wake of the United States' go-ahead to international institutional lending to Hanoi. The bank's board will meet at the end of October to agree about $350 million in loans, earmarked for three areas. The loans under consideration are for agriculture, a schools project and highway construction. Although President Bill Clinton last week gave US companies the go-ahead to bid for World Bank and Asian Development Bank-related projects, there are not likely to be many pickings for contractors from outside Asia in the first crop of developments, according to World Bank officials.