Deterministic and Monte Carlo methods are regularly employed to conduct lattice calculations. Monte Carlo methods can effectively model a large range of complex geometries and, compared to deterministic methods, they have the major advantage of reducing systematic errors and are computationally effective when integral quantities such as effective multiplication factor or reactivity are calculated. In contrast, deterministic methods do introduce discretization approximations but usually require shorter computation times than Monte Carlo methods when detailed flux and reaction-rate solutions are sought. This work compares the results of the deterministic code DRAGON to the Monte Carlo code Serpent in the calculation of the reactivity effects for a pressurized heavy water reactor (PHWR) lattice cell containing a 37-element, natural uranium fuel bundle with heavy water coolant and moderator. The reactivity effects are determined for changes to the coolant, moderator, and fuel temperatures and to the coolant and moderator densities for zero-burnup, mid-burnup [$3750 MWd/t(U)$] and discharge burnup [$7500 MWd/t(U)$] fuel. It is found that the overall trend in the reactivity effects calculated using DRAGON match those calculated using Serpent for the burnup cases considered. However, differences that exceed the amount attributable to statistical error have been found for some reactivity effects, particularly for perturbations to coolant and moderator density and fuel temperature.

## References

1.
Marleau
,
G.
,
Hébert
,
A.
, and
Roy
,
R.
,
2007
, “
A User Guide for DRAGON, Release 3.05 E
,”
Institut de génie nucléaire, Département de génie mécanique, Ecole Polytechnique de Montréal
2.
Leppänen
,
J.
,
2013
, “
PSG2/Serpent: A Continuous-energy Monte Carlo Reactor Physics Burnup Calculation Code
,”
VTT Technical Research Centre of Finland
, Finland.
3.
Hurst
,
D. G.
,
1997
,
Canada Enters the Nuclear Age: A Technical History of Atomic Energy of Canada Limited as Seen from Its Research Laboratories
,
McGill-Queen’s University Press
,
.
4.
Marleau
,
G.
,
2001
, “
DRAGON Theory Manual Part 1: Collision Probability Calculations
,”
Institut de génie nucléaire, Département de génie mécanique, Ecole Polytechnique de Montréal
5.
Koning
,
A.
,
Forrest
,
R.
,
Kellett
,
M.
,
Mills
,
R.
,
Henriksson
,
H.
, and
Rugama
,
Y.
, eds.,
2006
, “
The JEFF-3.1 Nuclear Data Library
,” ,
OECD
, Paris, France.
6.
Leszczynski
,
F.
,
Lopez Aldama
,
D.
, and
Trkov
,
A.
, eds.,
2007
, “