RE: N-16 Levels

["Lieskovsky, Miro" <MLieskovsky@nbpower.com>]

Stewart and the group:

Interesting thought; could you, please, forward me any private responses?
Thank you in advance.

If the core age (Pu content) is significant then the CANDU (PHWR) hard gamma
fields may also change with MOX fuel.  (The gamma fields during reactor
operation in the areas around active systems, i.e., coolant and moderator,
are predominantly due to the N-16 fields. The prompt gammas from the core
are minor.) 

Regards,
Miroslav Lieskovský 
Health Physicist 
NB POWER - PLGS
P.O. BOX 600
Lepreau, N.B.
Canada, E5J 2S6 
tel. (506) 659 7421
fax. (506) 659 6507
mlieskovsky@nbpower.com <mailto:mlieskovsky@nbpower.com> 



  -----Original Message-----
From: JSBland@aol.com [mailto:JSBland@aol.com]
Sent: January 11, 2000 5:17 PM
To: Multiple recipients of list
Subject: N-16 Levels


I have been asked a question related to N-16 production at a PWR and any 
dependency on core life.  Does N-16 production increase with core life?  I 
have examined the difference in the neutron energy spectrum between U-235 
fission and Pu-239 fission.  With a 9.6 MeV neutron energy threshold for the

O-16(n,p)N-16 reaction, it appears that the higher neutron energy spectrum 
from Pu-239 should yield a higher N-16 production rate later in core life. 
But, I don't recall (nor can I find) any data to support this hypothesized 
increase.  I have also examined the issue of prompt gammas from fission that

would yield high energy gammas that could be mistaken for N-16, especially 
while looking at a wide energy band for identification purposes (3 to 7.5 
MeV, over which I have no control).  In this case, the U-235 spectrum yields

more gammas in this energy band than does the Pu-239 spectrum.
Unfortunately 
for me, this is not a research project, just a "can you help explain this,"
 so I have no resources available for measurements.   Any help or
suggestions 
are appreciated.
J. Stewart Bland
(jsbland@aol.com)
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