This week, National Symphony concerts come in pairs. Last night conductor Rafael Fru hbeck de Burgos and the orchestra, with guest artist Nathan Milstein, completed the first set, repeating Tuesday's program.

It is a graphic index of Milstein's extended career to realize that he first played with the National Symphony 40 years ago. Though his brilliance and power have diminished, he still retains that capacity for rapid flights of seemingly effortless passage-work that have always amazed his admirers. This agility came forth as he moved through the familiar territory of the Beethoven Violin Concerto, particularly in the decorative displays of the first movement cadenza. Fru hbeck gave Milstein the most sympathetic of accompaniments, carefully following his lead in matters of tempo and dynamics.

Applying himself to Debussy in the other half of the program, Fru hbeck demonstrated once again his ability to bring freshness to well-known works through his impeccable craftsmanship. In both the "Two Nocturnes for Orchestra" and "La Mer" every note was given its precise weight and each layer of the finely wrought textures was alloted its exact place. The resulting clarity and transparency brought forth a new sense of Debussy as the master of orchestral detail, a welcome change from overly misty evocations that too often blur his intent. The interpretation may not have ravished the senses, but it certainly cleared the air.

The orchestra members contributed some nicely shaded performances, especially in the softer passages, and there were lovely solos from the woodwinds.