how to use fnd_global.conc_request_id as default value in sqlload ctl file?

I have a sqlload program to load data into DB table, so when I submit the concurrent to run the sqlload program, and one column group_id need to be default as concurrent request id in control file, I have tried fnd_global.conc_request_id,but return -1,so any suggestion would be appreciate.

my control file:

OPTIONS(SKIP=1)

LOAD DATA

INFILE *

INTO TABLE cux.xxar_sessions

APPEND

FIELDS TERMINATED BY ','

OPTIONALLY ENCLOSED BY '"'

TRAILING NULLCOLS

(  company_code,

   period_num,

   contract_id,

   client_id,

   brand_id,

   session_id "cux.xxar_sessions_s.nextval",

   group_id "fnd_global.conc_request_id"