Cognos failover connection to Oracle 11g2 RAC

[Mastron]

I made some reports in report studio.
This reports make a select queries to oracle. Oracle work in cluster - RAC.
This repots views by direct urls like http://localhost/ibmcognos/cgi-bin/cognosisapi.dll?b_action=cognosViewer&ui.action=run&ui.object=%2fcontent%2fpackage[%40name%3d%27DQ_package%27]%2freport[%40name%3d%27Indicator_A_micchecking_1_7_orig%27]&ui.name=Indicator_A_micchecking_1_7_orig&run.outputFormat=&run.prompt=true
For this report i made JDBC datasource that use oracle thin driver and oracle net descriptor like this:
(DESCRIPTION =
   (ADDRESS_LIST =
      (ADDRESS =
         (PROTOCOL = TCP)
         (HOST = 10.2.100.62)
         (PORT = 1521)
      )
      (ADDRESS =
         (PROTOCOL = TCP)
         (HOST = 10.2.100.63)
         (PORT = 1521)
      )
      (ADDRESS =
         (PROTOCOL = TCP)
         (HOST = 10.2.100.64)
         (PORT = 1521)
      )
      (LOAD_BALANCE = on)
      (FAILOVER = on)
   )
   (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = DB_RAC.DOMAIN.COM)
      (FAILOVER_MODE=       
         (TYPE=select)       
         (METHOD=BASIC)       
         (RETRIES=20)       
         (DELAY=15)
      )
   )
)

Report refreshing every minute
If i shutdown oracle istance that currently use by report- report after selfrefreshing fails with error   "java.sql.SQLRecoverableException: No more data to read from socket"
and report is in this state until i make refresh in web browser manually.
After maually refreshing report create new session and connect to new oracle node.
Where i can set up autmatically reconnection in case when session fail, or for example set up openning new session on every report self refreshing?