PL/SQL :: XML Aggregate Function And Out Of Process Memory

I am getting most of the time 'out of process memory' when i run the 'ord' procedure.here i am providing the tables and the procedure.

i have 2 table orders which holds distinct values, and departments table has ordvalue column holds long string of values for a particular record from orders table. for example if the values in orders table as follows:

ord_code ord_level ordid ordstatus ord_num user utimestamp
SR11          1 2 A          101 V     SYSDATE
SR11          1 2 A          102 V     SYSDATE
SR11          1 2 A          103 V     SYSDATE
SR11          1 2 A          104 V     SYSDATE
SR11          1 2 A          105 V     SYSDATE
SR11          1 2 A          106 V     SYSDATE
SR11          1 1 B          101 R     SYSDATE
SR11          1 1 B          102 R     SYSDATE
SR11          1 1 B          103 R     SYSDATE
SR11          1 1 B          104 R     SYSDATE
SR11          1 1 B          105 R     SYSDATE
SR11          1 1 B          106 R     SYSDATE

ETC...
AT TABLE departments data will be like this

ord_code ord_level ordid ordstatus ord_num user utimestamp
SR11          1 2 A          101,102,103,104,105,106 V sysdate
SR11          1 2 B          101,102,103,104,105,106 R sysdate

from the get_ord procedure the data aggreates using the xmlelement and gets as a long string value into departments table of ord_num column.

CREATE TABLE test.orders
(
ord_CODE VARCHAR2(4 BYTE) NOT NULL,
ord_LEVEL VARCHAR2(1 BYTE) NOT NULL,
ordID NUMBER(5) NOT NULL,
ordstatus VARCHAR2(1 BYTE) NOT NULL,
ord_num NUMBER(3) not null,
user VARCHAR2(8 BYTE),
UTIMESTAMP DATE
[code]...