ML110450403
| ML110450403 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 01/10/2011 |
| From: | Smed T Studsvik Scandpower |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| L-MT-11-009, TAC ME4790 SSP-09/444-C, Rev 0 | |
| Download: ML110450403 (38) | |
Text
ENCLOSURE2 MONTICELLO NUCLEAR GENERATING PLANT RESPONSE TO REQUESTS FOR ADDITIONAL INFORMATION FOR THE LICENSE AMENDMENT REQUEST TO REVISE THE MINIMUM CRITICAL POWER RATIO SAFETY LIMIT IN REACTOR CORE SAFETY LIMIT 2.1.1.2 RAI QUESTION 3 - STUDSVIK SCANDPOWER REPORT SSP-091444-C, "GARDEL BWR - MONTICELLO NPP POWER DISTRIBUTION UNCERTAINTIES," REV. 0, JANUARY 10, 2011 (30 pages follow)
Stu dsvi kruScandpower Report: SSP-09/444-C Rev 0 NON-PROPRIETARY GARDEL BWR - Monticello NPP Power Distribution Uncertainties Thomas Smed 2011.01.10 17:25:50
+01,'00' Date Prepared by:
Thomas Smed Digitally signed by David W. Dean DN: cn=David W. Dean, o=Studsvik
. Scandpower, Inc.,
email=david.dean@studsvikscandpower.com, D...
c=USa,,:.
.- "" Date: 2011.01.10 12:27:23 -05'00' Reviewed by:
David Dean Date
/
Jerry Umbarger 2011.01.10 13:28:14 -05'00' Date Approved by:
Jerry Umbarger
SSP-09/444-C Rev 0 Non-Proprietary GARDEL BWR - Monticello NPP Power Distribution Uncertainties Revision History Revision Number 0
Description Non-Proprietary - same as May 2009 Proprietary Date January 2011 ii StudsvCiScandpower
GARDEL BWR - Monticello NPP SSP-09/444-C Rev 0 Power Distribution Uncertainties Non-Proprietary Abstract This document describes the methodology used to evaluate the uncertainties in the adaptive relative power distribution within GARDEL. These uncertainties are dependent on the quality of the simulation model employed, as well as on the reactor's instrumentation uncertainties.
By utilizing the symmetric TIP positions in Monticello Nuclear Power Plant, the measurement uncertainties, and indirectly, the calculational uncertainties, can be obtained.
The adapted power is based on calculated power adjusted with observed differences between calculated and measured TIP response. By regarding the adapted power as a weighted average of measured and calculated power, a basis for evaluating the overall uncertainty is established.
The power distribution uncertainties are explored using a variety of perturbed simulation cases to emulate modeling errors. The first method requires a set of idealized cases, in which the calculated TIP values are fed back into SIMULATE to demonstrate the ability of the adaption model to reduce bundle power uncertainty. The second method uses the plant-measured TIP values to power-adapt perturbed and unperturbed cases to more realistically assess he adaption model. The decrease in difference between the adapted power for the perturbed and unperturbed cases drives the overall uncertainty reduction.
Finally, because TIP+LPRM-adaption is used in online monitoring, the additional uncertainty contribution from LPRM drift and the impact of basing the adaption on the prior TIP calibration is determined.
Uncertainties when all TIP machines are in service for 35 day TIP interval:
Gnodal i
]
Cradial R [/
]
Uncertainties with one out-of-service TIP machine for 35 day TIP interval:
anodal = []
0 radial Uncertainties when all TIP machines are in service for 70 day TIP interval:
Gnodal =
[
]
aradial = ((
]
Uncertainties with one out-of-service TIP machine for 70 day TIP interval:
0 nodal = ((
yaodia. =
1]
Studsvik"Scandpower
SSP-09/444-C Rev 0 Non-Proprietary GARDEL BWR - Monticello NPP Power Distribution Uncertainties Table of Contents A bstract.......................................................................................................................................
iii
- 1.
Purpose and Scope.................................................
1-1
- 2.
Normal Distribution Statistics............................................
2-1
- 3.
Measurement and Calculation Uncertainties.................................................................
3-1
- 4.
TIP-Adapted Power Uncertainties...................................................................................
4-1 4.1 The Perturbation Method........................................................................................
4-2 4.2 Method 1: Calculated TIP Responses Used for Adaption....................................
4-5 4.3 Method 2: Measured TIP Responses Used for Adaption......................................
4-6
- 5.
LPRM+TIP-Adapted Power Uncertainties........................................................................
5-1 5.1 LPRM Handling During TIP/LPRM Calibrations.....................................................
5-1 5.2 LPRM Handling Between TIP/LPRM Calibrations.......................
5-2 5.3 LPRM+TIP-Adapted Power Distribution Uncertainties...................................
5-3
- 6.
Overall Uncertainty............................................................................................................
6-1
- 7.
R eferences.........................................................................................................................
7-1 iv Studsvik-Scan dpower iv
GARDEL BWR - Monticello NPP SSP-09/444-C Rev 0 Power Distribution Uncertainties Non-Proprietary
- 1. Purpose and Scope This document describes the methodology used to evaluate the uncertainties in the adaptive relative power distribution within GARDEL. These uncertainties are dependent on the quality of the simulation model employed, as well as on the reactor's instrumentation uncertainties.
The adapted power is based on calculated power adjusted with observed differences between calculated and measured TIP response. By regarding the adapted power as a weighted average of measured and calculated power, a basis for evaluating the overall uncertainty is established in section 2.
By utilizing the symmetric TIP positions in Monticello, the measurement uncertainties, and indirectly, the calculational uncertainties, are obtained in section 3.
The power distribution uncertainties through adaption are assessed in section 4 using a variety of perturbed simulation cases to emulate modeling errors. The first method requires a set of idealized "baseline" cases, in which the calculated TIP Values are fed back into SIMULATE as measured data to illustrate how well the adaption can recover from a known perturbation. The advantage of this method is that the "true" values are available and the ability to recover can be studied.
The second method uses the plant-measured TIP values to power-adapt perturbed and unperturbed cases. The decrease in difference between the adapted power for the perturbed and unperturbed cases drives the overall uncertainty reduction. Both methods can be utilized to assess the impact of one TIP machine being out of service.
In online monitoring, TIP+LPRM-adaption is used. Therefore, the additional uncertainty contribution from LPRM drift and the impact of basing the adaption on the prior TIP calibration is determined in section 5 by developing a TIP-calibration uncertainty to account for the LPRM-to-Studsvik-Scandpower
SSP-09/444-C Rev 0 Non-Proprietary GARDEL BWR - Monticello NPP Power Distribution Uncertainties TIP correction that GARDEL-BWR regularly performs. There are two effects that have to be considered; the drift of the LPRM detectors, and the fact that the shape of the TIP deviations from the last TIP calibration is employed in the time between TIP calibrations. By using the recorded GARDEL data, a good estimate of the total impact of these two effects can be obtained by comparing the adapted power immediately before a TIP calibration with the adapted power immediately after a TIP calibration.
Finally, all uncertainty pieces are combined to obtain the overall uncertainty in section 6.
The methodology employed is based on the observed differences in the TIP measurements and was applied to analyze Monticello Nuclear Station cycle 22-24 data.
Studsvik-Scandpower 1-2
GARDEL BWR - Monticello NPP SSP-091444-C Rev 0 Power Distribution Uncertainties Non-Proprietary
- 2. Normal Distribution Statistics Total bundle power uncertainty is comprised of a calculational uncertainty piece and a measurement uncertainty piece, which are assumed to be independent of each other. To develop a methodology for combining these uncertainties, we use the following definitions:
Xt = true parameter Xm = measured parameter X, = calculated parameter em
=
= measurement error X,
c
- X-calculation error X,
StOoX
= XI Xý observed difference Xm The unbiased estimator for the variance of a normal-distributed variable is given by where S2 I (XI,_ 3)2
- Thus, N
0 i=
(2.1)
Using the definitions prescribed above, the expected value of the respective errors, Y, for N independent measurements of 6, is given by Studsvik'Scandpower 2-1
SSP-09/444-C Rev 0 GARDEL BWR - Monticello NPP Non-Proprietary Power Distribution Uncertainties N
N As q, and E, were assumed to be independent, the following relationship exists and will serve as the basis for total bundle uncertainty. calculations, 0;L
=.
+0.
(2.2)
Assumption 1: The adapted power can be considered to be a weighted average of measured and calculated values The value of adapted power in any location can be expressed as a weighted average of measured power and calculated power:
X. = (1-S,)Xc +SmXm (2.3)
Equation (2.3) cannot be applied immediately, since we do not have direct access to the measured nodal and bundle powers. Moreover, the values of S, and I-S, will vary by core location. To distinguish these local values from the core-wide average, we use Sm 1-Sm to denote core-average values.
If the uncertainties in the measurement are independent of the uncertainties in the calculation, the variance of X,, o-., can be expressed as:,
S(1Sm 2.
+
C20 (2.4)
We will determine the variance of the TIP adapted power by evaluating 1-S. (section 4) and conservatively assume that Sm =1.
2-2 Studsvi kScandpower
GARDEL BWR - Monticello NPP SSP-091444-C Rev 0 Power Distribution Uncertainties Non-Proprietary Assumption 2: The predicted-to-measured TIP response ratio provides a measure of the deviation in the predicted power from the true power The adaption model in GARDELJSIMULATE assumes that the measured-to-calculated TIP ratio, TIPRAT, provides an accurate measure of the relative deviation in calculated power in the surrounding bundles:
APOW1 TIPMEA" 0=
TIPRAT POWC
-TIP CAL where APOW1 = TIP-adapted power (also denoted as POWM)
POWC = Predicted (calculated) power TIP4EA = Plant-measured detector response TIPCAL = Predicted (calculated) detector response This is reiterated in a more formal fashion in equation (4.1) in section 4, the TIP-adapted power equation.
The calculation of uncertainties for the adaptive method relies on the assumption that the TIP deviations provide a measure of the nodal power deviations. This is a reasonable assumption, since, in principle, the calculation of the flux can be made with the same accuracy throughout the core. The uncertainty on the calculation of the reaction rates in the instrument tubes is of the same magnitude as that on the calculation of the flux, and hence the power, in the fuel pins.
The uncertainty for calculating the average power in a node is smaller than in the pins, since the pin-power calculations are summed over all the pins in the node. This means that the estimate of a. for the predicted (calculated) TIP response, as derived in chapter 3, constitutes a conservative estimate of the uncertainty of the calculated nodal power.
Studsvik'Scandpower
SSP-09/444-C Rev 0 GARDEL BWR - Monticello NPP Non-Proprietary Power Distribution Uncertainties Since each measurement location in the core may have a unique value of 5. that can satisfy equation (2.4), estimating the effective value of the core-wide distributions, (F--Sm) and S-,m, will be crucial.
We will assess the effective value of (F-S-)
by using the adaption model in two variations of a perturbation method:
- 1. The calculated TIP values from a "baseline" case will be used to power-adapt a series of perturbed cases to illustrate the capabilities and limitations of the adaption model. A measure of the effectiveness of this adaption will be used to define the distribution, (I-Si).
- 2. The actual plant-measured TIP values will be used to power-adapt a set of base cases and a series of corresponding perturbed cases to establish the ability of the adaption model to recover the expected result. A measure of the effectiveness of this adaption will be used to define the distribution, (I-S 2).
For the strategy outlined above, it is straightforward to estimate the impact of one out-of-service TIP machine.
Note that when we analyze equation (2.4) for the purpose of determining the uncertainty, (FS-
) and S, will be treated like two variables A and B, and conservative estimates for the two variables will be generated so (1--S)+ S = A+ B > 1. A conservative estimate of 1.0 for S.m, the weighting of the measurement uncertainty, will be used.
2-4 Studsvik-Scandpower
GARDEL BWR - Monticello NPP SSP-09/444-C Rev 0 Power Distribution Uncertainties Non-Proprietary
- 3. Measurement and Calculation Uncertainties A central part of the uncertainty analysis is determining a. and a,, the uncertainties associated with the measurement and the calculation. As shown in Figure 3-1, the core design and detector layout in Monticello is quite advantageous. The large number (13) of symmetric or close-to-symmetric instrument locations provides a good statistical basis for the estimation of the measurement uncertainties.
Studsvik'scandp ower 3-1
SSP-09/444-C Rev 0 Non-Proprietary GARDEL BWR - Monticello NPP Power Distribution Uncertainties Figure 3-1. Monticello Nuclear Station Core Layout The uncertainty in the measured TIP response is assessed using a method that takes advantage of the symmetric detector locations in the core. Assuming that TIPs x and x' are symmetric, then Studsvi k-Scandpower 3'2
GARDEL BWR - Monticello NPP Power Distriblution Uncertainties SSP-09/444-C Rev 0 Non-Proprietary Ii rZ(IPMAffv ~TIPMEfi)
-(TPCA14 - TIPCAg) 1 (3.1) where N
= Total number of symmetric TIPs in the core In the above method, the term (T!PCAg -T!PCA4,)
accounts for slight asymmetries that exist during operation.
When oa is determined from the measurements, q, can be determined from equation (2.2).
Results of this calculation are presented in Table 3-1 for 44 TIP measurements in Monticello cycles 22-24.
Nodal Axial Radial
.o~
[Eml
((Ml
[Em.]1 ml3
[mlB Table 3-1. Uncertainties on Measured and Calculated Detector Response The calculational uncertainty, q-,, is the calculational uncertainty of the predicted (calculated)
TIP response. As noted in chapter 2, this provides a measure of the uncertainty of the calculated nodal and bundle power.
StudsVik"Scandp-ower 3-3
SSP-091444-C Rev 0 Non-Proprietary GARDEL BWR - Monticello NPP Power Distribution Uncertainties This Page Is Intentionally Blank Studsvik-Scandpower 3-4
GARDEL BWR - Monticello NPP SSP-09/444-C Rev 0 Power Distribution Uncertainties Non-Proprietary
- 4. TIP-Adapted Power Uncertainties The adaption model in GARDEL/SIMULATE assumes that the measured-to-calculated TIP-signal ratio, TYPJAT, provides an accurate measure of the relative deviation in calculated power in the surrounding bundles. TIPPT is expanded to non-instrumented locations by radially weighting the instruments up to five fuel assemblies away from the current bundle.
TIPRAT is then applied to POWC to calculate APOW1, the TIP-adapted, relative nodal power distribution as follows, c.f. Reference 1:
E TIPRAT*,'w, APOWk = POWC.k 1=1 (4.1) tiw 1=1 where APOW1 = TIP-adapted power (also denoted as POWM)
POWC = SIMULATE-3-predicted (calculated) power TIPRAT= Ratio of measured-to-predicted relative reaction rate in the detector location k
= Node index n
= Bundle index w
= Weighting factor for the l TIP surrounding bundle n GARDEL uses a weighting-factor array based on the following equation: 1 Studsvik'Scandpower
SSP-09/444-C Rev 0 GARDEL BWR - Monticello NPP Non-Proprietary Power Distribution Uncertainties The adaption model will take-into account bundles up to five positions away from the instrument, yielding the weighting-factor matrix shown below.
27P_/AT remains constant between TIP measurements and GARDEL's adaptive post-processor calculates APOWj after each SIMULATE core supervision calculation (typically once per hour at stable reactor conditions). The purpose of the APOWJ calculation is to eliminate deviations in the calculated power distribution observed in the latest TIP comparison.
One limitation to this method is that deviations in non-instrumented assemblies will only partially affect IPRAT. The relative thermal neutron flux in an instrumented location is affected by the contributions from the four neighboring fuel assemblies. The power deviation in a particular node will be the result of the node's intrinsic deviation plus the contribution from the deviations in its neighboring nodes. It is apparent that the detectors cannot supervise any local deviation that may take place in the non-instrumented assemblies; however, the supervision system is strong in detecting global deviations.
4.1 The Perturbation Method To estimate the weighting of the calculational uncertainty in the adaption model, (FS-
)
a number of cases have been simulated for which input parameters have been perturbed to emulate errors in the calculation scheme. All of these cases have been evaluated for two different scenarios:
- 1. The calculated TIP responses from the baseline case have been used as "measured" signals for the adaption that is performed on. the perturbed case.
- 2. The actual measured TIP responses have been used for the adaption that is performed on the perturbed case.
4-2 Studsvik-Scandpower
GARDEL BWR - Monticello NPP Power Distribution Uncertainties SSP-091444-C Rev 0 Non-Proprietary Each method will assess the ability of the adaption model to compensate for a perturbation in an effort to characterize the calculational component of the overall uncertainty. The following "global" parameters have been disturbed: ((
Method 1 Uncertainty components:
- POWC,
= Calculated power, unperturbed baseline case, i.e. "true power"
- APOWC,
= Difference between calculated power in the perturbed case and POWC, AAPOWlP = Difference between TIP-adapted power in the perturbed case and POWCt By first idealizing the cases using the calculated TIP values and assuming the plant has measured the TIP values perfectly, the experiment becomes more controllable. All deviation from. the original case is due to the perturbation and the TIP response calculation. That is, the assessment of the adaption model compensation is directly proportional to the deviation of APOWCP + AAPOW], from zero. In this way, the individual mechanisms of the adaption model.
can be understood without having to account for errors introduced by plant measurements.
Studsvik-Scandapower "4-3
SSP-09/444-C Rev 0 GARDEL BWR - Monticello NPP Non-Proprietary Power Distribution Uncertainties Method 2 AAPOW1. +ATIPMEA 1 Plant-measured 4 TIP response
- Pertulrbed case*
Aatdcs APOWCP +AAPOW1P +AI Uncertainty components:
- POWC,
= Calculated power, unperturbed case
- AAPOW1,
= Difference between TIP-adapted power in the unperturbed case and POWC.
APOWCv
= Difference between calculated power in the perturbed case and POWC, AAPOWIP = Difference between TIP-adapted power in the perturbed case and POWCP ATIPAE4 = Uncertainty introduced by plant-measured detector response The second method more realistically models the ability of the core to adjust for a perturbation.
The additional uncertainty introduced by using the plant-measured TIP response means that less of the total overall uncertainty can be compensated for by the adaption model. In areas of low power, the plant-measured TIP response to the perturbation will not be as strong as in areas of higher power. Because the adaption model is based on measured TIP values, this has the net effect of lowering the ability of the adaption model to correct for perturbations. In the.
case of method two, the recovery capability is directly proportional to the deviation of APOWCP + AAPOWlp from AAPOWI..
4-4 Studsvik'Scandpower
GARDEL BWR - Monticello NPP SSP-091444-C Rev 0 Power Distribution Uncertainties Non-Proprietary 4.2 Method 1: Calculated TIP Responses Used for Adaption After.adaption, the average remaining error (F-S-) is estimated by:
(_-T, =st d(APOWl -POWC,)
F std(POWCP -POWC,)
(4.2)
.where APOW1P = TIP-adapted power, perturbed case (adapted using calculated response from baseline case)
- POWC,
= Calculated power, unperturbed baseline case, i.e. "true power" POWCp
=Calculated power, perturbed case Table 4-1 shows the average and standard deviation of (F-S 1) for a variety of perturbations on all available cases (43 TIP-calibrations over 3 cycles).
All TIP Machines in Service One TIP Machine Out of Service Perturbation case avg (I1-s) std (1 -S) a vg (I-std (I1-Si)
_d...
],
((U]
((U))[UII
((U_
U
[
11 M 11 I[U Table 4-1. (1-S,) for various perturbed cases, adapted with calculated TIP values.
Studsvik"Scandpower
SSP-091444-C Rev 0 Non-Proprietary GARDEL BWR - Monticello NPP Power Distribution Uncertainties 4.3 Method 2: Measured TIP Responses Used for Adaption After adaption, the average remaining error (f--s2 ) is estimated by:
(I-2) =std(APOW1, - APOW1I) std(POWCP - POWCU)
(43) where APOW1P = TIP-adapted power, perturbed case (adapted using measured response)
APOW1.
= TIP-adapted power, unperturbed case (adapted using measured response)
POWCP
= Calculated power, perturbed case POWC, = calculated power, unperturbed case Table 4-2 shows the average and standard deviation of (s) for a variety of perturbations on all available cases (38 TIP-calibrations over 3 cycles).
All TIP Machines In Service One TIP Machine Out of Service Perturbation case
)
)
s)
(-
)
((1 11
((a11
((m ]
[l 11
((
11
[1U11 1 1
((--
[I--11
((I-l
((-
11 Table 4-2. (1-S 2) for various perturbed cases, adapted with calculated TIP values.
Both methods produce consistent results. The different perturbations resulted in different perturbations on the power. Table 4-3 summarizes the size of the disturbances.
4-6 Stu dsvik'"Scan dpower 4-6
GARDEL BWR - Monticello NPP Power Distribution Uncertainties SSP-091444-C Rev 0 Non-Proprietary Perturbation case rms(APower) m iE
[m]i Table 4-3. Size of perturbation An overall evaluation of (1--S-.)
was based on a weighted average of the results in which perturbation with larger disturbance was given a greater weight. In order to obtain a conservative estimate, 2-is added to the estimate of (1*-S).
a vg ( avg( -Sm)
+ 2std (a g (1 I _))
where avg (F-S) =The average of (*S.S) over all TIP calibrations Results are given in equations (4.4) and (4.5) below, cf Tables 4-1, 4-2 and 4-3:
All TIP machines in operation:
(F-S).
- ((nl]n One TIP machine out of service:
(4.4)
(4.5)
(1-S.)
= [lii))
Studsvik'Scandpower 4-7
SSP-091444-C Rev 0 Non-Proprietary GARDEL BWR - Monticello NPP Power Distribution Uncertainties Including the uncertainty of 2-, the results become All TIP machines in operation:
(1--Sm)""rai-[El
]
One TIP machine out of service:
(4.6)
The conservative values in equations (4.6) and (4.7) will be used in the evaluation of overall uncertainty.
4-8 Studsvi kScandpower
GARDEL BWR - Monticello NPP SSP-09/444-C Rev 0 Power Distribution Uncertainties Non-Proprietary
- 5. LPRM+TIP-Adapted Power Uncertainties GARDEL continuously uses the incoming LPRM detector signals with following purposes:
- 1. Apply an LPRM correction to the power distribution in order to evaluate APOW2, the LPRM+TIP-adapted power distribution.
- 2. Perform a vedfication of the applicability of the LPRM depletion modeling by comparing the incoming LPRM signals versus the deviations observed during the latest TIP calibration.
In addition, GARDEL includes a detector depletion model to account for sensitivity changes between TIP/LPRM calibrations.
5.1 LPRM Handling During TIPILPRM Calibrations Immediately after a TIP/LPRM calibration was accepted, GARDEL will evaluate the LPRM-to-TIP reference ratio, PRMREF, as PRMREF = LPRMCAL LPRAM where LPRMCAL = Predicted LPRM signal computed using an LPRM-type detector LPRAMEA =Measured LPRM signal using a TIP-type detector PRJREF is a snapshot of the expected calculation-to-measurement deviations in the LPRM positions at the TIP calibration times. At the axial locations of the LPRMs, LPRMMEA is equal to TIPMEA.
GARDEL also maintains PRMSCF, the LPRM calibration factors, so that PRMSCF =
PRM Studsvik-Scandpower 5-1
SSP-09/444-C Rev 0 GARDEL BWR - Monticello NPP Non-Proprietary Power Distribution Uncertainties where PRM
= Un-calibrated, plant-measured LPRM signals This calculation is an attempt to capture the drift in LPRM signal since it was last calibrated to match the TIP signal. If an LPRM spans a node boundary, an average of the measured TIP values in the two nodes containing the detector is taken.
GARDEL also resets all depletion calibration factors, PR.MCF, to 1.0 and begins updating them again after the calibration.
5.2 LPRM Handling Between TIP/LPRM Calibrations Although the LPRMs are calibrated to produce the same signal as the TIPs independent of detector type, they cannot be directly compared to predicted (calculated) LPRM signals. The LPRM signal must first be corrected for possible miss calibration, depletion effects, and computed reaction rate if the detector types are different.
GARDEL evaluates a pseudo-LPRM signal, LPRLM, as PR.MSCF LPRMP = PRM x PRMREF x PRMDCF where PRM
= Un-calibrated, plant-measured LPRM signals PPiREF = LPRM-to-TIP reference ratio PRMSCF = LPRM signal calibration factors PRMCF = LPRM depletion calibration factors The pseudo-LPRM signal can now be compared to the calculated LPRM signal to define PRM&AT, the LPRM adaption distribution PRMRT =LPRIVIP PRMCAL where LPTRP
= Measured LPRM signal, corrected 5-2 StudsvikScandpo wer
GARDEL BWR - Monticello NPP SSP-091444-C Rev 0 Power Distribution Uncertainties Non-Proprietary PRMCAL
= Calculated LPRM signal 5.3 LPRM+TIP-Adapted Power Distribution Uncertainties To evaluate the LPRM+TIP-adapted relative power distribution, PRMiRAT is used to evaluate an LPRM-based TPJRAT distribution, TIPRATrnd, as TmRA7m(z) = TPRA T(z) x PRMRAT(z) where z
= Axial node index PRiVIRAT(z) values are-evaluated by linear interpolation in between the four LPRM levels TIPRATpwp is applied in the same way as TIPRAT to obtain APOW2, the LPRM+TIP-adapted relative power distribution APOW2 = TIPRATp,?m x POWC
= PRMiAT xTIPRATxPOWC
= PRMRAT x APOW1 Note that immediately after a TIP/LPRM calibration, TIPRATpp ; TIPRAT and APOW1 -APOW2. This makes the additional uncertainty in going from APOW1 to APOW2 easy to assess from data. Immediately after a TIP calibration, the additional uncertainty is small and it grows continuously until the next calibration. A good estimate of the maximum additional uncertainty due to the transition from APOW1 to APOW2 can be obtained by calculating the standard deviation of the difference in APOW2 immediately before and after the TIP calibration o-; T = std[(APOW2- - APOW2) --(POWC- - POWC+)]
(5.1) where o-* T is the uncertainty immediately before a TIP calibration due to LPRM drift and the fact that TPYRAT used for the adaption is from the last calibration APOW2-
= APOW2 immediately before a TIP calibration Studsvik'Scandpower
SSP-09/444-C Rev 0 GARDEL BWR - Monticello NPP Non-Proprietary Power Distribution Uncertainties APOW2+
= APOW2 immediately after a TIP calibration POWC-
= POWC immediately before a TIP calibration POWC+
= POWC immediately after a TIP calibration For practical reasons, the real time between "immediately before" and "immediately after" the TIP calibration is up to twenty-four hours. The term (POWC- -POWC*) is included to account for the changes in core conditions during this time. For the available data, the additional nodal uncertainty for TIP intervals up to 35 days is (35) [
(5.2) where o-a_ (35) is the additional nodal uncertainty due to LPRM drift and variation in TIPRATfor a 35 day TIP interval Correspondingly, the additional bundle uncertainty is, abunfe (35)
(5.3) where bundle,,,,,'
oD T (3 5) is the additional bundle uncertainty due to LPRM drift and variation in T!PRAT for a 35 day TIP interval a~o-dar(70) -
l
](5.4) where o-'odal (70) is the additional nodal uncertainty due to LPRM drift and variation in TIPRAT for a 70 day TIP interval The additional bundle uncertainty for 70 day TIP interval is,
-bunfe (70)
(5.5) where o-DjIe (70) is the additional bundle uncertainty due to LPRM drift and variation in TIPRATfor a 70 day TIP interval StudsvikScandpower
GARDEL BWR - Monticello NPP Power Distribution Uncertainties SSP-091444-C Rev 0 Non-Proprietary
- 6. Overall Uncertainty The overall nodal and bundle uncertainties for LPRM+TIP-adapted power immediately before a TIP calibration are determined by the following equations:
,nodal
'12-2 2
2 (odao APOW2 =V
--mJ 'acax
+Gcrad +Clm
+ ( D_'T bundle 2
undle' 2
+
bundle o.POW2 =
Mcad
+
.,ma +
Y
=
cr d + CrD_T (6.1)
(6.2)
Credit for improvement through adaption is only applied to the calculated axial deviation contribution to the nodal uncertainty and not at all in the bundle uncertainty. The values of 1-S, include the additional 2o-as from equations (4.6) and (4.7). The calculational uncertainty in the axial direction is determined by requiring that equation (6.3) is satisfied:
2 C2
=C2
,~tX+cad '*
(6.3)
Uncertainty Nodal Bundle Source
', ((i
))
((i]
Table 3-1
((*
1]
((
))
Table 3-1,
-c((in))
Eq (6.3) crnj,(35)
[R ))
((M ))
Eqs (5.2),(5.3) rDz- (70)
[
((
))
Eqs (5.4),(5.5)
Table 6-1. Summary of uncertainties Studsvik-Scandpower 6-1
SSP-091444-C Rev 0 Non-Proprietary GARDEL BWR - Monticello NPP Power Distribution Uncertainties Combining the results from Table 6-1, equations (4.6), (4.7), (6.1), and (6.2) the overall uncertainties for the LPRM+TIP-adapted nodal and bundle power, with all TIP machines in service and one TIP machine out of service are given below:.
Table 6-2. Overall LPRM+TIP-adapted power uncertainties for 35 day TIP interval All TIP Machines in Service One TIP Machine Out of Service Nodal Bundle Nodal Bundle Table 6-3. Overall LPRM+TIP-adapted power uncertainties for 70 day TIP interval The available data supports interpolation of CD_T. For example, if a 50 day TIP-interval is utilized, the resulting uncertainties are given by equations (6.4), (6.5) and table 6-4:
o-fl7da'( 50) =2.7 a Dbne (5O0) =1. 6 (6.4)
(6.5)
Table 6-4. Overall LPRM+TIP-adapted power uncertainties for 50 day TIP interval Studsvik-Scan dpower 6-2
GARDEL BWR - Monticello NPP SSP-091444-C Rev 0 Power Distribution Uncertainties Non-Proprietary
- 7. References
- 1.
"SIMULATE-3 Adaptive Model for BWR On-Line Core Monitoring", STUDSVIK/SOA-96/19 (1996).
- 2.
"ADPS3B Program Description", SSP-04/430, rev. 1 (2006).
- 3.
"Qualification of Reactor Physics Methods for Application to Monticello," (NSPNAD-8609 Rev. 2).
Studsvik-Scandpower 7-1
SSP-091444-C Rev 0 Non-Proprietary GARDEL BWR - Monticello NPP Power Distribution Uncertainties This Page Is Intentionally Blank Studsvik'Scandpower 7-2
ENCLOSURE3 MONTICELLO NUCLEAR GENERATING PLANT RESPONSE TO REQUESTS FOR ADDITIONAL INFORMATION FOR THE LICENSE AMENDMENT REQUEST TO REVISE THE MINIMUM CRITICAL POWER RATIO SAFETY LIMIT IN REACTOR CORE SAFETY LIMIT 2.1.1.2 GLOBAL NUCLEAR FUEL (GNF) PROPRIETARY INFORMATION AFFIDAVIT (3 pages follow)
Global Nuclear Fuel - Americas AFFIDAVIT I, Anthony P. Reese, state as follows:
(1)
I am Manager, Reload Design and Analysis, Global Nuclear Fuel - Americas, LLC ("GNF-A"), and have been delegated the function of reviewing the information described in paragraph (2) which is sought to be withheld, and have been authorized to apply for its withholding.
(2) The information sought to be withheld is contained in Enclosure 1 of GNF's letter, VSP-NMC-EK1-11-001, V. S. Perry (GNF-A) to R. Harris (Xcel Energy, Inc.), entitled "GNF Response to NRC Requests for Additional Information (RAIs) 1, 2, 4, 5, and 6 on Monticello Cycle 26 SLMCPR Submittal," dated January 14, 2011.
GNF-A proprietary information in Enclosure 1, which is entitled "Response to NRC RAIs 1, 2, 4, 5, and 6 on Monticello Cycle 26 SLMCPR Submittal," is identified by a dotted underline inside double square brackets. ((This sentence is an example. f3)11 A "((" marking at the beginning of a table, figure, or paragraph closed with a "))" marking at the end of the table, figure or paragraph is used to indicate that the entire content between the double brackets is proprietary.
In each case, the superscript notation {3) refers to Paragraph (3) of this affidavit, which provides the basis for the proprietary determination.
(3)
In making this application for withholding of proprietary information of which it is the owner or licensee, GNF-A relies upon the exemption from disclosure set forth in the Freedom of Information Act ("FOIA"), 5 USC Sec. 552(b)(4), and the Trade Secrets Act, 18 USC Sec. 1905, and NRC regulations 10 CFR 9.17(a)(4), and 2.390(a)(4) for "trade secrets" (Exemption 4).
The material for which exemption from disclosure is here sought also qualify under the narrower definition of "trade secret", within the meanings assigned to those terms for purposes of FOIA Exemption 4 in, respectively, Critical Mass Energy Project v. Nuclear Regulatory Commission, 975F2d871 (DC Cir. 1992), and Public Citizen Health Research Group v. FDA, 704F2d1280 (DC Cir. 1983).
(4) Some examples of categories of information which fit into the definition of proprietary information are:
- a.
Information that discloses a process, method, or apparatus, including supporting data and analyses, where prevention of its use by GNF-A's competitors without license from GNF-A constitutes a competitive economic advantage over other companies;
- b.
Information which, if used by a competitor, would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing of a similar product;
- c.
Information which reveals aspects of past, present, or future GNF-A customer-funded development plans and programs, resulting in potential products to GNF-A;
- d.
Information which discloses patentable subject matter for which it may be desirable to obtain patent protection.
The information sought to be withheld is considered to be proprietary for the reasons set forth in paragraphs (4)a. and (4)b. above.
(5)
To address 10 CFR 2.390 (b) (4), the information sought to be withheld is being submitted to NRC in confidence. The information is of a sort customarily held in confidence by GNF-A, and is in fact so held. The information sought to be withheld has, to the best of my knowledge and belief, consistently been held in confidence by GNF-A, no public disclosure has been made, and it is not available in public sources. All disclosures to third parties including any required transmittals to NRC, have been made, or must be made, pursuant to regulatory provisions or proprietary agreements which provide for maintenance of the information in confidence.
Its initial designation as proprietary information, and the subsequent steps taken to prevent its unauthorized disclosure, are as set forth in paragraphs (6) and (7) following.
(6)
Initial approval of proprietary treatment of a document is made by the manager of the originating component, the person most likely to be acquainted with the value and sensitivity of the information in relation to industry knowledge, or subject to the terms under which it was licensed to GNF-A. Access to such documents within GNF-A is limited on a "need to know" basis.
(7) The procedure. for approval of external release of such a document typically requires review by the staff manager, project manager, principal scientist or other equivalent authority, by the manager of the cognizant marketing function (or his delegate), and by the Legal Operation, for technical content, competitive effect, and determination of the accuracy of the proprietary designation.
Disclosures outside GNF-A are limited to regulatory bodies, customers, and potential customers, and their agents, suppliers, and licensees, and others with a legitimate need for the information, and then only in accordance with appropriate regulatory provisions or proprietary agreements.
(8)
The information identified in paragraph (2) is classified as proprietary because it contains details of GNF-A's fuel design and licensing methodology.
The development of this methodology, along with the testing, development and approval was achieved at a significant cost to GNF-A or its licensor.
The development of the fuel design and licensing methodology along with the interpretation and application of the analytical results is derived from an extensive experience database that constitutes a major GNF-A asset.
(9)
Public disclosure of the information sought to be withheld is likely to cause substantial harm to GNF-A's competitive position and foreclose or reduce the availability of profit-making opportunities. The information is part of GNF-A's comprehensive BWR safety and technology base, and its commercial value extends beyond the original development cost.
The value of the technology base goes beyond the extensive physical database and analytical methodology and includes development of the expertise to determine and apply the appropriate evaluation process.
In addition, the technology base includes the value derived from providing analyses done with NRC-approved methods.
The research, development, engineering, analytical, and NRC review costs comprise a substantial investment of time and money by GNF-A.
The precise value of the expertise to devise an evaluation process and apply the correct analytical methodology is difficult to quantify, but it clearly is substantial.
GNF-A's competitive advantage will be lost if its competitors are able to use the results of the GNF-A experience to normalize or verify their own process or if they are able to claim an equivalent understanding by demonstrating that they can arrive at the same or similar conclusions.
The value of this information to GNF-A would be lost if the information were disclosed to the public.
Making such information available to competitors without their having been required to undertake a similar expenditure of resources would unfairly provide competitors with a windfall, and deprive GNF-A of the opportunity to exercise its competitive advantage to seek an adequate return on its large investment in developing and obtaining these very valuable analytical tools.
I declare under penalty of perjury that the foregoing affidavit and the matters stated therein are true and correct to the best of my knowledge, information, and belief.
Executed at Wilmington, North Carolina this 1 4 th day of January 2011.
Ant P.eese Manager, Reload Design and Analysis Global Nuclear Fuel - Americas, LLC
ENCLOSURE4 MONTICELLO NUCLEAR GENERATING PLANT RESPONSE TO REQUESTS FOR ADDITIONAL INFORMATION FOR THE LICENSE AMENDMENT REQUEST TO REVISE THE MINIMUM CRITICAL POWER RATIO SAFETY LIMIT IN REACTOR CORE SAFETY LIMIT 2.1.1.2 STUDSVIK SCANDPOWER PROPRIETARY INFORMATION AFFIDAVIT (2 pages follow)
.~~.
I Jerry Unmbarge a*r
- a follows::
1a....mainChiefFinaflcial Officer of Studsvik. Scandpower. Inc..(SSP) and have reviewedheinmation described in paragraph 2 which is sought.to.be withheld.
- 2.
he nfomaionsouht o e wthhldis contained in the attachment, "GARDEL.
"BWM~onticeelo NPP Power Distribution Uncetainties," datedsJuly 24,2009.
SSP proprietar.einforation iin diate' d by enclosi g it in doubie brackets..The basis fat.prprietay det..
h natiop0 is jprovided itnparzraph 3.
In:nakih g this application for withholding of proprietary. information of which it is the owner, SSP relies- *n the exemption from disclosure set fortin.the
- Feed. omflnfor iaion At "('FOA"),
5US3 Sec1. 552(b)(4), and the Trade SecretsAct$ 18* kSC"Seci8 19005 and NRC regulations IOCFR 9*1.7(a)(4) and
'.2.390(a)(4) fotrade secrets and commercial or fiancirai6nrmation obtained froma.personand -ri~eed or.nidenti.. *(Exemption4)4The.material for.
'whicheI emption'from disclosure is hete s6ffght is all 'confidential commercial Information".
- 4. The oroation sought to b wtb_ held is considered to be proprietary.for the following :reasons:
- .Infdrmation that discloses a proc4Ks method and. supprtin data~ and,.
anases. where: prevention of its use by SSP's competitors without liýense
- .:.from SSP constitutes a competitive' ecnomic advantage over: other companies;
..Inormation which,i'f ua-ed by a competitori would reduce his-expenditure of resources*or np rove his competitive:positio.. Mi the design, manua-ctue..
shipm*{it. installation, assurance of quality.
.licensing of a s*miar product.
5-" To aiddress the. 10 CFRi2390on(b)()ethe information sought to be withheld is being submitted to NRC in confide~nce. The itformfation is ofa asort customarily held idfconfidenrceby SSP. and is in fact so held. The information sought to:be w"i.hhefldlas, to. the. best of my kntowledge and-blief, consistently been held.in
- byconden bySSP, nplic idi§cture has been.
ade,: and it is not available in public source.s. Aldihclbs..u.r.e.s f oihird par.ti,es including, any. re.quired transmittals t6 NRC) iav been made, or mausi t e ima e, p4Furqnt to iegulatory provisions or propnetary agreements which provide for maintenance of the information in confidence;
- 6. : The..(iobraiionlidentifiead inpatagrap2is? classified as p-oprietary because it contn*:
details of SSP.'s power distribution. uncertainties. methodology.,The.
.:*deveopnet of.hihethods used in these analysese was achieved at a significant.
cost to SSP.
- 7. Public dislosure of te informaftion sought.to be withheld is likely to cause s.ubsitantial harm-to: SSP'"s icomrpeitive.iPosition and foreclose oryreduce the availability. of p*rfitmaking opporum eopprrtunities.
The pwe-r diktiibutioi, uncertainties m.ethodo*glgis a part of SSP's GARDEL: coeemonitoring system, and its comiercial value extends beynd. t*he original development cost.
=.
- {*i =
- - ::.*{: :: ": :. : f:,
.:ipi: i : : : :1"
- .i::i : :,:: : :..:i i:
- i ii".iii*7: : :. :/ : *. :. ::., -. i..:
The precise value of the expertise to devise an evaluation process a apily tha e
y correct analytical methodology.is difficult to. qhantify,.buft it clearly is substanrtial.
SSP's competitive advantage will be lost if its:competitors are ablie to P::se.te results of the SSP's experience.
The Value of this information to SSP would be Ii6st if the info*rimtion.were..
..disclosed to the public. Making such informatin avaiable tocompetitors' withiut:::
theirbhving been required to undertake a simitar expenditure of r*sgources w6ould unfairly provide competitors with a windfall, and.depiv SSP of the bpprfunity.
.to exercise itscompetitive advantage to seek an adequate retubn onits. investment...
I declare under pena of perjury that the foregoing' afavitdthe: mat ter**s:s stated therein are true and correct To the best of my kIowledge, information and elietk.
Executed at Newvton. Massachusetts, this 27"t day of January 201f.-
Inc.
12~