The Montgomery County school board, in a move to preserve some day care programs, voted last night to keep open an elementary school in Bethesda that was slated for closing.

The board opted to keep open Bradley Elementary School, located near the National Institutes of Health, instead of nearby Radnor Elementary, which has less space for day care programs. On a 4-to-3 vote, the board voted to close Radnor next June.

Both schools are losing enrollment.

School Superintendent Edward Andrews originally recommended closing Bradley because school planners estimated it would cost at least $2 million to renovate the school and bring it up to adequate safety standards. Radnor required little in the way of renovation but it is smaller and less able to accommodate day care children from other schools in the area that may be shut down.

There was some question whether money will be available to complete the costly renovation of Bradley. Board Vice President Elizabeth Spencer voted against closing Radnor, saying that if Bradley cannot be renovated children might still have to be transferred from that school in several years.

In drawing up the master plan for closing, day care was not taken into consideration in assessing the levels of use of school facilities. But Bethesda area community groups protested vehemently during public hearings last month and urged the board to consider the need for day care programs that are based in elementary schools.

In arguing against the superintendent's recommendation to close Bradley last night, several board members noted the need to maintain day care programs and said that this factor outweighed the cost of renovating the Bradley facility. The day care programs in the Bethesda area primarily serve parents who work at NIH, which is the county's largest employer.

The board voted unanimously last night to close the Ayrlawn school, also near the NIH in Bethesda, which has the largest school-based day care program in the county.

At least half of Ayrlawn's day care program, and perhaps more, could be relocated at Bradley, but far fewer students could have been transferred to Radnor if that school had stayed open.

Several board members, including President Carol F. Wallace, favored keeping both Radnor and Bradley open. But Superintendent Andrews argued that one school had to close.

"I cannot envision a fiscally independent school board keeping both of those schools open, when one needs renovation and when both have declining enrollments," Andrews told the board.

Board member Marian L. Greenblatt said it would be "fiscally irresponsible" to keep both schools open. Spencer and board member Blair Ewing added that it would be educationally unsound not to consolidate students from the schools into one building.

The board also voted last night to close Brookmont Elementary, whose community has agreed all along to the closing, and Congressional and Montrose elementaries, both of which have minority enrollments greater than 40 percent.