Your boss asks you to calculate the design stress for a brittle nickel-aluminide rod she wants to use in a high-temperature design where the cylindrical component is stressed in tension. You decide to test rods of the same diameter and length as her design in tension to avoid the correction for the effective area (or effective volume in this case). You measure an average stress of 673 MPa and a Weibull modulus (m) of 14.7 for the nickel-aluminide rods. What is the design stress in MPa if 99.999% of the parts you build must be able to handle this stress without fracturing?