Officials are hopeful that the federal courthouse in Boston will reopen for business on Tuesday after a fire on Thursday forced it to close, officials said. Damage is being assessed and the necessary repairs are being made, said Patrick J. Sclafani, spokesman for the General Services Administration. The administration will ultimately decide when the courthouse will reopen, Sclafani said. If the court does not reopen on Tuesday, individual judges will make a determination in conjunction with US District Chief Judge Mark L. Wolf and the US Marshals Service on whether to postpone cases or hold hearings elsewhere, said Susan Goldberg, spokeswoman for the federal courts.