Atomic Safety and Licensing Appeal Board will hear an oral argument on the appeal of the Long Island Lighting Company, 2 p.m., NRC Public Hearing Room, Fifth Floor, East-West Towers, 4350 East-West Highway, Bethesda. LILCO is appealing the board's partial decision of April 17 regarding licensing for the Shoreham Nuclear Power Station on Long Island. Participants will include representatives from LILCO, Suffolk County, New York State and the Nuclear Regulatory Commission staff. Call 301/492-7715 for information.

*The Free South Africa Movement holds a news conference to discuss today's march honoring those killed in the recent crackdown in South Africa, 10 a.m., Room 2172, Rayburn House Office Building. Participants in the march will assemble at noon on the grounds of the Washington Monument and proceed to the State Department's diplomatic entrance at 22nd and C streets NW. Call 547-2550 for information.

*The Department of Agriculture reports on Aug. 1 crop production.

*The Census Bureau reports on June housing completions. TUESDAY

*The Occupational Safety and Health Administration is the topic of a policy symposium, "What Can We Expect From OSHA," with panelist Margaret Seminario of the AFL-CIO and facilitator Frank Wallick of the UAW Washington Report, 4 to 6 p.m., Second Floor Conference Room, United Auto Workers, 1757 N St. NW. Call 828-8500 for information.

*National Housing Conference housing forum luncheon features William Gainer of the General Accounting Office, 12:15 p.m., Zenger Room, National Press Club, 529 14th St. NW. Call 662-7502 for information. WEDNESDAY

*The Social Security Administration holds ceremonies commemorating the 50th anniversary of the signing of the act, 11 a.m., at national headquarters, 6201 Security Blvd., Woodlawn. Platform guests will include Margaret M. Heckler, secretary of the Department of Health and Human Services; Ford B. Ford, undersecretary of labor, and Martha A. McSteen, acting commissioner of Social Security. Call 245-1272 for information.

*The Census Bureau reports on inventories and sales of June manufacturing and trade.

*National Press Club V-J Day observation includes a luncheon with Clark Clifford at 12:30 p.m. and a reunion of Pacific war correspondents, 7 p.m., both in the Ballroom, at the press club, 529 14th St. NW. Call 662-7502 for information. THURSDAY

*The Federal Reserve Board reports on July industrial production, money stock measures and factors affecting reserves of depository institutions.

*The Department of Housing and Urban Development reports on yields on FHA-insured, new-home, 30-year mortgages. FRIDAY

*Overseas Development Council and Earthscan will hold a seminar for journalists, "Food Production in Africa: Policies for the Longer Term," beginning with registration at 8:45 a.m. on Aug. 22, Conference Room D, Carnegie Endowment for International Peace, 11 Dupont Circle NW. Registration is requested by Friday. The seminar will look at the role of short-term relief in relation to Africa's long-term needs, how famines can be prevented and what kind of policies are needed if Africa is to break out of a cycle of drought and famine. Call 234-8701 for information.

*The Census Bureau reports on July housing starts.

*The Federal Reserve Board reports on capacity utilization, manufacturing and materials and the condition of large commercial banks.