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Application exemple on simple PWR complete system

Data file description

ref: View 003.dat, download 003.dat

Each data group in the input file input.dat is documented in details as follows.

read: introduces read data group
&S00gen :generic data list for primary side
l9=1 : single loop loop1 representation
epstau= .01 : precision criterion used for resolving 0/0 type numerical indetermination
osplit= f: no spitting of c and a
owvp= t [Option;floW;Volumetric] loop flow will be specified, in Lstl1, as pump volumetric flow
S00gvg: generic list for steam-generators if they exist
epsqgv= .000001 [EPsilon;thermal power Q;Generator;of Vapor] convergence criterion for automatic adjustment of heat-exchange area in the ini process
omqgv= 2.5 [OMega;QGV] relaxation factor for the previous adjustment
The adjustment must generally be over-relaxed .
The convergence process can be monitored on the console at execution time and omqgv may be adjusted accordingly.
swagv= [transverse Surface;for floW;in Annulus;of GV] constant, default, transverse flow area of SG annular space for all SG.
A level-dependant area may also be defined by an interpolator following Lstn1
vadgv= [Volume;Annulus space;+ Dome;GV] common total volume for A and N
! if the SG are not of the same size, vadgv should be redefined on the Lstn
xygv= relaxation multiplier (x means "times") for level corrections in automatic level control. A value of 1 is generally adequate
read / Plots see later
aza= [Accretion (or "Augmentation") of elevation Z;in Annular space ] not used unless euler is invoked
cfra= [Coefficient;of FRiction;A] idem
gga= [twinGGle;A] average length/flow area ratio of A (idem)
va= [Volume;A]
hsb= [entHalpy;Sortie;Bottom] common enthalpy for a, b & loop cold leg imposed at initialization
bsb= [Boron;Sortie;B] same as for hsb
xwab= [fraction X;floW;from A;to B] xwab=1 means that all the flow outgoing a enters and mixes with water in b before entering c
core_config Input here the data for all the configurations igr which will be potentially present in the course of the transient.
i9gr=2 : [I;9 max;of confiGuRations] igr=1 for rodded configuration; igr=2 for unrodded configuration
Zgri_sec: Polygonal time-interpolator for upper limit zgri of each igr
sec= [time SEC] time values: here a record of values, terminated with / for delimiting the number of values (here:4)
zgri= [Z;for each IGR] corresponding zgri, entered as a 2-dim Fortan array (the first index changes the most rapidly):
[zgri((isec=1,4), (igr=1,i9gr)) ]
Dgri_sec time-interpolator for groups insertion after reactor trip (Arret Urgence).
pic 01 shows for example the upper position trajectory of each configuration for a safety trip at sec=50
Lstau : Input data for protection system will be detailed later (reactor protection system).
sec_drop= 1000/ sec_drop, the time at which the rod configurations starts dropping is normally determined by the protection system. Entering a large value (default) prevents drop activation. Entering a value <secmax forces drop at sec_drop.
! namelist record terminated by /
&Lstc: generic namelist for the core
i9c= [I9;C] max value of neutronic intervals ci used for flux calculation.
i9c=1 simulates point-kinetics
k9c= 1 [CK;9 max] max value of nodes ck
it9fc= 1 [: [ITeration;9;for nuclear power F;in C] only 1 flux iteration
it9dsc= 0 : [IT9;DSec;C] no automatic increment of dsec adjustments
dhyc= [Diameter;HYdraulic;C] cooling channel hydraulic diameter (used if dnbr is calculated
epsuc= .001 [EPSilon;fUel pellet;temperatUre;C] accuracy crit. for initializing temperature field in fuel pellet
sfc= [transverse Surface;for nuclear power F;Core ] [] active (power generating) core transverse area
swc= [transverse Surface;for mass floW;C ] core flow area
xfuc= [fraction X;of nuclear power F;generated in fUel pellet;C ]
it9fc= [ITeration;9;FC]
it9dsc= [IT9;for DSec;C]
The other data are not relevant for the present application
Lstuc data list for average fuel rod uc
ruc= [Radius;fUel pellet;Core] fuel pellet radius
drcc= [Delta;Radius;Cladding;Core] fuel rod clad thickness
drgc= [Delta;Radius;Gap;Core] thickness of the pellet to clad gap
qhgc= [thermal Q;Heat exchange coefficient;of Gap;C]
units: W/(m 2 s)
xfruc= [fraction X;of nuclear power F;deposited in each region R;of core fuel pellet UC] the pellet is spit into 4 equal-area regions; 4*.25 corresponds to uniform power radial distribution
xuruc= [fraction X;temperatUre;in Region;of UC] relative neutronic reactivity weight of each region; .3,4*0,.7 means 30% to pellet center and 70% to pellet edge, which overweights pellet edge
Lstci: data list for each ci [Core;Interval]
f2ci= [nuclear power F;generated at end-of-step 2;in CI ]
As i9c=1, f2ci is here the total initial (at eos 2 of sec=0 step) nuclear power
Lstck The core is partitioned into k9c thermal nodes ck, with uniform thermal properties (h, b, u,...) like for any thermal node of the system.
i9ck= [last 9;interval I;of node CK]
each ck spit into
i9ck(ck)-i9ck(ck-1) equal height intervals
azck= [AZ;CK] axial thickness of CK (here the active height)
cfrck= [Coefficient;FRiction;CK] no used here
vck= [water Volume;CK]
vuck= [Volume;fUel pellet;in CK ].
"U" represents the metallic conductor attached to a node: fUel rod, pipe metallic wall, ...
vck + vuck = total volume of active core in CK
&Lstg Generic namelist for neutronic data tables attached to each confiGuration ig
iv9g= [index I;volumetric mass V;last 9;G] number of tabulation points for the water volumic massvm
Lstgg tabulates neutronic variables depending only on confiGuration index ig and water volumetric mass vm
amjg= {lAMbda; family J}
deferred neutron precursor decay constants (unit: 1/s)
! common set for all confIGurations
vmg= [Volumetric;Mass;confIG] tabulated values of vm, entered as 1-dim array
vmg(iv=1, i9vg)
beg= [total BEta;for each confiG] total delayed-neutron fraction
bejg= [BEta;for each family J of delayed neutrons;for each confiG] Entered as 2-d fortran array
bejg((j=1;j9g), (igr=1,i9gr))
default value for i9gr: 6

Lstrvg: tabulation list for reactivity for each confiGuration.
The input data have been adjusted to correspond to a water temperature coefficient of -1e-5/K, and a Doppler fuel temperature coefficient of -4e-5/K
rog= [Reactivity;base value O;confiGuration] entered as
rog(iv, igr)
roug= [Reactivity;of base value O;U-derivative;G] ∂rg/∂u where
u ≡ sqrt(effective fuel temperature - coolant temperature).
roug simulates the fuel temperature Doppler effect
rouug= [RO;second derivative /U;G]: ∂rug / ∂u
Lstsxvg: data list for neutronic macroscopic cross-sections [SX] tabulated, like reactivity, versus [iV] and [iG]
sdog= [macroscopic "Section";of Diffusion] Coefficient of diffusion (units: cm-1)
svog= [Section;for Velocity;O;G] inverse of average neutron Velocity
sknog= [Section;Kappa/Nu;OG] ratio of nuclear power to fissions source
snog= [macroscopic cross-Section, νΣf fission;OG ] fission macroscopic cross-section Σf * ν (average number of neutrons emitted per fission)
u-derivative of SNOG

The hot-channel is referenced as [C7]

Lstuc7 Are solely entered under those list hot-channel values which differ from their corresponding average channel ones given above under Lstuc
xuruc7= [XURU;C7] used for editing purpose only; record 1,5*0. will result in editing hot channel center temperature.
Lstfxyvg list collects hot-channel radial [XY] form factors [F] also tabulated vs (iv,ig)
fxyog= 2*1.55, 2*2.5 means: fxy=1.55 for rodded (ig=1) core, fxy=2.5 for unrodded (igr=2) core, not affected by density effect vm.
azd= [AZ;Dome]
cfrd= [Coeff;FRiction;D] used in calculating flow by-pass through D
vd= [water Volume;D]
xwcd= [fraction X;of Core outlet mass floW;penetrating and mixing with Dome water]
xwld= [fraction X;of floW;by-passed from Loop outlet;to D] to insure a "cold dome" effect by reducing primary hot water inventory in order to mitigate the consequences of loss-of-coolant accident.
The pressu sub-system includes the components Outlet, pressu eXpansion line and Pressu vessel.
p3= [Pressure;3 ]initial primary pressure; p3 represents the last, current pressure used for calculating primary T&H properties; not to be confused with p2, the pressure updated at eos "2" by closure of the primary volume balance
omo= [relaxation factor OMega; for Outlet] for controlling possible instabilities resulting from partially explicit h-balance of O
vo= [Volume;O]
xwco= [fraction X;of floW;from Core outlet;to and mixing with water in O] normally = 1 - xwcd
Lstx: generic list for pressu eXpansion line
it9x= [ITeration ;max number 9;X] iterations used in homogeneous pressu model
m9x= [expansion line node M;last 9;for X]
Lstxm properties for the eXpansion line nodes xm(1:m9x)
azxm= [Accretion;elevation Z;XM] for horizontal part of X azxm=0. Used for calculating pressure drop in X
cfrxm= [Coefficient;of FRiction;of XM]
vxm= [Volume; of node XM]
Lstp list for pressu vessel
m2p= [total water Mass;at eos 2;of P] initial (at eos of sec=0) water (liquid+vapor) mass
oqp= [logical Option;for heat Q;injection Y;into P]
oqyp= [Option;for heat Q;injected Y;in P ] idem for pressure control by electric heaters
Lsts list for pressurizer Spray
bss= [Boron;at Sortie;of Spray line] initial value
hss= [entHalpy;at Sortie;of Spray line] initial value must verify the pressu h-balance
qyp = wss * (hl0 - hss)
where hl0 represents the primary system 0 saturated Liquid entHalpy
wss= [floW;at Sortie;of Spray line] here a fixed value; normally resulting from pressure control
loop_1 Data group for the single loop loop_1 represented.
Lstl1 List for loop l=1.
i9l= [node Index;last 9;of loop L]
ipl= [node I;into which the Pump is inserted;for loop L]
xwl= [multiplier X;of floW;for L]
xwl= 3 indicates a nuclear plant with 3 identical loops and SG's
Itp_sec: list for sec-interpolated data
sec= [sec values record ] here 5 values (terminated with /)
wvpl= [floW;Volumetric;of Pump;in Loop] here a constant value of 7.75637 m³/s
Lstli1 [data LiST;for nodes LI;loop 1] entered as records of i9l values.
jqli= [SG secondary node J;receiving heat Q;from primary node LI]
For the nodes nj above the sg tubes bundle (in the riser), jqli=0 of SG
azli= [AZ;of LI] In the node ipl where the pump is inserted, the pump manometric head is subtracted from the geometric value of azli
cfrli= [CFR;LI]
eqli [thickness (Epaisseur);of metallic part (loop piping, SG tubes) exchanging heat Q;with LI]
ggli= [litheness (length/transverse area) GG;of LI]
qli= [heat power Q;received by LI] used, outside the SG nodes, to simulate the electrical power dissipated to thermal power in the node where the pump is inserted
qauli= [heat Q flux;caused by Accretion;of metal temperature U; in LI] in other words: conductivity coefficient (W/(m*K) of metallic part associated with li
qvuli= [thermal power Q;for heating the Volume;of LI] or volumetric heat capacity of metallic part (J/(m³*K)
rfli= [thermal Resistance;of heat transfer Film; LI] inverse of heat-transfer coefficient
sqli= [Surface;for heat-exchange Q;LI] for the sg nodes li=2:3, the heat-exchange area of tubes contained in the node
vuli= [Volume; metallic condUctor;attached to LI] for the sg tubes, volume of the tubes contained in LI
wyli= [mass floW;injected Y;into LI]
Group for the secondary side of steam_gen_1 inserted in loop_1. As a rule, it is referenced by the index N with n=l
Lstn1: data list for sg n
j9n= [index nJ;last 9;of sg N] in the vapor generation part [Core;of N] each secondary node nj exchanges heat with a primary node i3 [3: belongs to ascending branch of the gv tubes and a node i4 to the descending part.]
nj = jli(i3) = jli(i4)
cfran= [CFR;Annulus;of N] lumped value supposed to be independent of the water level of an
gga= [flexibility GG ;AN] average length/area of an; should vary with elevation of water in an. gga enters in acceleration term of the recirculation loop kinetic balance and influences the transient part only of recirculation flow w2an. As zan is kept constant by the sg level regulation, it makes sense to enter a constant value.
hyan= [entHalpy;feed-water injected Y;into AN] may be time-dependent through Itp_sec interpolator
p3n= [Pressure;3;N]as for the primary system, p3n is the last pressure used in calculating the t&h data. To be discerned from the eos pressure p2n updated for closing volume balance
v2an= [water Volume;at eos 2;AN]: initial (eos at time-step 0) water volume; depends of regulated water level in AN
van= [Volume;AN]:target water volume for an water level regulation. Normally van=v2an
w2an= initial recirculation flow
wyan= [floW;of feed-water injected Y;into AN] initial feed-water flow
Actually the values of w2an and wyan are entered for the purpose of forcing the initial recirculation ratio R = w2an / wyan;
As the actual initial wyan is calculated from the secondary side enthalpy balance, the initial w2an is adjusted from w2an = R * wyan
zvan= [ratio of water elevation Z;to water Volume;in AN]
if the transverse an area changes with elevation, zvan must be entered via Itp_sec interpolator
sec= time interpolation points
qgvn= [net thermal power Q;yielded by Generator of Vapor;N] calculated from the system global power balance:
including the nuclear power f2c + the contribution of pressu heater qyp, and the primary pump thermal power qli(ipl) dissipated in node ipl.
qgvn is kept constant during 5 s for stationarity check and cut to 0 in short time interval .001 s
wzpdn= [vapor floW;discharge Z;Pressure-dependant;coefficient of Dome;N] calculated from the chocked discharge law:
wzpdn =wzpdn*SQRT(p3n/vvn)
which implies that the discharged steam is saturated (volumetric mass vvn). wzpdn is chosen here to open at sec=5 (in .001 s time interval) the discharge valve in order compensate exactly the qgvn cutback at sec=5, and keep the same opening thereafter
Lstnj1 defines the data for the secondary nodes nj(1:j9n). The notations are similar as for the primary nodes.
rf3nj= [RF;for upstream 3 tubes;NJ]
rf4nj= [RF;for downstream 3 tubes;NJ]
swnj= [transverse Surface;for floW;in NJ]
After having gone though the input data, the meaning of most of the variables to be plotted should be clear.