ML18288A369
| ML18288A369 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 10/31/1990 |
| From: | Advanced Nuclear Fuels Corp |
| To: | NRC/OI |
| References | |
| ANF-88-054(NP) (A), NUDOCS 9011130082 | |
| Download: ML18288A369 (65) | |
Text
I I ANF-88-054(NP) (A)
I.
~
ADVANCED NUCLEAR FUELS CORPORATION PDC-3: ADVANCED NUCLEAR FUELS CORPORATION POWER DISTRIBUTION CONTROL FOR PRESSURIZED WATER REACTORS AND APPLICATION OF PDC-3 TO H.B. ROBINSON UNIT 2 OCTOBER 1990 A Siemens Company
r~-
ADVANCED NUCLEAR FUELS CORPORATION AN F-88-054(N P) (A)"
Issue Date: l 0/26/90 PDC-3: ADVANCED NUCLEAR FUELS CORPORATION POWER DISTRIBUTION CONTROL FOR PRESSURIZED WATER REACTORS AND APPLICATION OF PDC-3 TO H.B. ROBINSON UNIT 2
ANF-88-054(NP)(A)
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, 0, C. 20555 August 17, 1990 Mr. R. A. Copeland, Manage~
Reload Licensing Advanced Nuclear Fuels Corporation P. 0. Box 130
- Richland, Washington 99352-0130
Dear Mr *. Copeland:
SUBJ.ECT: ACCEPTANCE FOR REFERENCING OF TOPICAL REPORT ANF-88-054(P),
11 PDC-3: ADVANCED NUCLEAR FUEL CORPORATION POWER DISTRIBUTION FOR PRESSURIZED WATER REACTORS AND APPLICATION OF POC-3 TO H. B. ROBINSON UNIT 211 The staff has completed its review of the Topical Report ANF-88-054(P), 11 PDC-3:
Advanced Nuclear Fuel Corporation Power Distribution for Pressurized Water
- Reactors," submitted by the Advanced Nuclear Fuels Corporation (ANF) by letter of June 18, 1990. This rep9rt describes and justifies the~~se of the ANF PDC-3
- power distribution .analysis'**methodology, which has been developed by means of improvements and extensions to the NRC-staff-approved PDC-2 methodology.
We find the application of ANF-88-054(P) to be acceptable for referencing in license applications to the extent specified, and under the limitations delineated, in ANF-88-054{P) and the* associated NRC technical evaluation. The evaluation defines the basis for acceptance of this topical report.
We do not intend to repeat our review of the matters found acceptable as described in ANF-88-054(P) when the report appears as a reference in license applications, except to ensure that the material presented is applicable to the specific plant involved. Our acce~tance applies only to the matters described in the application of ANF-88-054(P).
!n accordance with procedures establish~d in NUREG-0390, Jt.js requested that the A~vanced Nuclear fuels Corporation~publish accepted versions of this topical report, proprietary and non-proprietary, within three months of receipt of this letter. The accepted versions shall iriclude an "A" (designating accepted) following the report identification symbol.
Should our criteria or regulations change so* as to invalidate our conclusions concerning the acceptability of the report, the Advanced Nuclear Fuels Corporation and/or the applicants referencing the topical report will be expected to revise and resubmit their respective documentation, or submit justification for the continued effective applicability of the topical report without revision of their respective documentation.
Since~
- Ashok c~-{~~i~::.
Division of Systems Technology Office of Nuclear Reactor Regulation
Enclosure:
ANF-88-054(P) *Evaluation
ANF-88-054(NP){A)
ENCLOSURE SAFETY EVALUATION FOR TOPICAL REPORT ANF-88-054(P)
"PDC-3: 'ADVANCED NUCLEAR FUELS CORPORATION POWER DISTRIBUTION CONTROL FOR PRESSURIZED WATER REACTORS AND APPLICATION OF PDC-3 TOH. B. ROBINSON UNIT 211 (TAC NO. 77234)
1.0 INTRODUCTION
By 1etter of June 18, 1990 (Ref. l), Advanced Nuclear Fuels Corporation {ANF) submitted far review the Topical Report ANF-88-054{P), 11 PDC~3: Advanced Nuclear Fuels Corporation Power Distribution* Control for Pressurized Water Reactors and Application of PDC-3 to H.B. Robinson Unit 2, 11 July 1988 *. The topical report consists of (1) a generic description and justification for the use of the ANF PDC-3 power distribution control analysis methodology, which can replace the previously used ,(NRC-staff-approved) PDC-2 methodology, and (2) a specific application of PDC-3 to H*. B. Robinson Steam Electric. Plant, Unit No. 2 (HBR2), which, for this submittal, is an example of the manner in which the methodology would be applied.
Carolina Power and Light Company. (CP&L) originally submitted ANF-88-054(P)
(Ref. 2) as a justification of proposed changes to the technical specification (TS) for HBR2. The proposed changes were to some of the required parameters and limits associated with the ANF system of analytical and operational control of power distribution limits as useq by HBR 2 in current and projected future operating cycles. These changes resulted from the.switch from PDC-2 to POC-3 methodology for the HBR2 analyses. In its review of the HBR2 submittal, the staff concluded that the PDC-3 methodology was acceptable as described in Topical Report ANF~88-054(P),.and for the specific application to HBR2, also described in the report. The following discussion of the evaluation of the report as a presentation of the ANF generic methodology is taken, for the most part, from the HBR2 safety evaluation.
ANF-88-054(NP)(A) 2 2.0 EVALUATION The ANF power distribution methodology relevant to ANF-88-054 pr1mari1y consists of (1) operator-controlled.limits on axial power distribution (based on control of relative power in the top and bottom of the reactor, expressed as ~
"axial offset" or "axial flux difference") and (2) the analytically determined V(Z) distribution (the maximized ratio of the axially dependent, total peaking \
factor F~(Z), during and following power maneuvers, to the equilibrium F~(Z) value at target offset conditions). These characteristics are a part of both current and future ANF methodologies and operations. The proposed changes do not affect operational procedures, but only affect the axial offset limits related to the allowed operations outside of the normal offset control band.
Although the PDC-3 methodology for calculating V(Z) retains previous general characteristics, several of its details have been changed. The primary differences are as follows:
- 1. The analysis of the core average radial and axial behavior in steady state and power maneuvers is perfonned *with 3-dimensfona1 (30) XTG (Ref. 3),
- rather than using the PDC-2 methodology of 1-dimensional (lD) XTG and conservative radial peaking factors (Fxy).
- 2. The set of power maneuver transients that is used in the analyses is an expansion of the PDC-2 set. This expanded set provides a more conservative set of-transient values for F~(Z) and the development of V(Z).
PDC-2 uses a 10 axial analysis generated by collapsing a 30 XTG model.* The suitability of the analysis has been verified by comparisons to experiment and has been previously reviewed and approved by the NRC and its consultants {see Reference 3). ANF has now developed a "sample" 30 XTG model covering a repre-sentative operating cycle and has- used it to compare the lD and 30 models in the development and justification of the generic PDC-3 methodology. The lD model was developed from the 30 using the PDC-2 methodology. Using the previously approved standard load-following transients for the* "sample" model
- and comparing the 30 and lD axial power distributions, ANF detennined that the
3 agreement in axial behavior is very similar. The 30 and lD XTG methods are equally acceptable for generating the axial component of V(Z) *. The 3D and 10 results will differ between the two methods only in the treatment of the radial component of the power distribution, and in that aspect PDC-3 will be more realistic. The staff's review of these analyses and comparisons indicate that the 30 methodology of PDC-3 is appropriate and acceptable~
For PDC-3 ANF has proposed an expanded set of load-following transients for the development of V(Z). From previous PDC-2 results the V(Z) limit could have been drawn less conservatively than it has been, p~rticularly near the core center. However, in its revi~w of the PDC-2 methods (Ref. 4), the NRC consultant, Brookhaven National Laboratory (BNL), noted that the BNL independent {parallel) calculations produ~ed slightly higher peaking factors
{from alternate load-following strategies) near the core centerline than those of A~F. However, ANF drew its final V(Z) limits as an extrapolated straight line* in the core center region, well above the calculated results, including the BNL results. The NRC review indicated that this extrapolation was acceptable, but that if a less conservative limit were to be proposed, 11 a more definitive analysis of the differences would be required. 11 To overcome the difference and enable the V(Z) limit to be drawn closer to the calculated values near the center, ANF has used the POC-3 additional load-following transients that bounded all possible modes of (allowed) operation, including those indicated in the NRC review. Other aspects of the PDC-3 parameter selection process remain the same as for POC-2.
The PDC-2 methodology uses three load-following strategies, each at beginning of cycle (BOC) and endof cycle (EOC) conditions. These strategies display extremes of operator control in operations at the limits of allowed offset banks about the offset equilibrium target. For PDC-3, ANF expanded this set to include six strategies (each at BOC and EOC). The additional strategies cover other extreme conditions (within allowed operations), including those suggested by the BNL calculations for PDC-2 and, for example, the effects *of fuel with natural enrichment "axial blankets" such as is *used in HBR2. The 12 cases in combination cover all apparent extremes of relevant allowed operation and should provide bounding transient peaking factors. These additions allow ANF
ANF-88-054(NP)(A) 4 '
I to draw the V(Z) limit closer to (but above) the data derived from the analysis, 1 particularly at the.core center, r~ther than the straight line extensio~ used
\
in the generic PDC-2. In its review of these changes, the NRC staff has concluded that ANF has provided a suitably bounding set of analyses by way of the expanded set of load-following cases in the PDC-3 methodology. Therefore, I the resulting V(Z) curve drawn as proposed is acceptable. The staff also concludes that ANF has suitably described and justified the generic PDC-3 methodology, including the use of 30 XTG and the extended set .of transient 1 cases. Therefore, this methodology, with the extended set of transient cases, is acceptable for use as described in ANF-88-054.
ANF applied the .PDC-3 methodology;*with the full JD XTG and the expanded set
. of operating modes, to,HBR2 :and *discussed this application as an example in the topical report. For this analysis, an HBR2-specific model was developed rather than using a generic model as had previously been perfonned with the PDC-2 methodology for the dev.elopment of the HBR2 technical specifications (TS); The parameters of Cycle 12 were used in the model._ These calculations produced new values for V(Z) and for the limits for allowed t1peration outside of designated offset bands. These values for V(Z) fanned the basis for the changes to the TS. The operating procedures and other aspect~ of the power distribution analysis and TS were unchanged. *The characteristics of Cycle 12 HBR2 differed from the generic POC-3 11 sample 11 plant in having (1) a lower power density; (2) lower control bank (D) reactivity worth, and (3) natural uranium axial blankets. As specified in the existing TS, ANF perfonned analyses for offset bands of both (plus and minus) 3 and 5 percent. ANF examined the effect of control rod worth by calculating V(Z) for the following rea~tivity worths of bank D:nomina1, (plus and minus) 15 percent, and (plus) 30 percent. A composite V.(Z) was produced from the maxima of these *result_s as a func~ion of Z. A bounding, limiting V(Z) was drawn above.the composite curve, which became the proposed TS.
In the currently approved ANF operational methodology for the control of power
- distribution, during operation below 90-percent power, small deviations outside of the allowed offset band are permitted for limited times. These limits were reexamined using the model of HBR2 Cycle 12. ANF performed calculations for
5 operations at various power levels outside the band beginning from various extremes within the band. Allowed deviations were determined for operation in both the 3- and 5-percent bands while at power levels from 90 to 50 percent.
These limits differed slightly from previous limits.
The NRC staff reviewed the "example" HBR2 calculations and concluded that the calculations were appropriate, the results were reasonable and proposed TS changes were acceptable. However, the staff noted that the model of HBR2 Cycle 12 used in the analyses had two significant characteristics relating to axial fue.l blankets and control *rod bank D reactivity worth, which would have to be preserved in future HBR2 cycles for the specific derived TS results to be valid. Departure from these limits would require new analyses. From this review, the staff concludes .:that. t/1e,. HBR2 analysis in ANF-88-054(P) is an acceptable example of the use' of the,-PDC-3 methodology.
3.0 CONCLUSION
S The staff h~s revi~wed the ANF topical report ANF-88-054(P) which provides the generic description and justification of the PDC-3 methodology and an example of it~: use by means of a~ HBR2-specific analysis. PDC-3 is an extended and improved version of the_staff-approved PDC-2 ANF methodology. PDC-3 uses 30 XTG models (rather than the PDC-2 10 models) to describe the core during non-equili.brium.operation, and uses an expanded set of load-following transients (compared to PDC-2) to provide a more conservative non-equilibrium correction factor, V(Z), for the ANF methodology for. power distribution analysis. The report presents comparisons of the 30 and 10 results and the effects of the extended load-foll.owing transtents.* Based on the review of this description and comparisons we have concluded that ANF submitted appropriate documentation. In addition, the generic PDC-3 methodology as described in the report satisfies staff positions and requirements and is acceptable for power distribution analyses of the type discussed in the report, such as the TS change analysis for HBR2 given as a~ example.
ANF-88-054(NP~(A) 6
4.0 REFERENCES
- 1. Letter and enclosure from R. Copeland, ANF, to Director of Nuclear Reactor Regulation, NRC, June 18, 1990, "Transmittal of ANF-88-054(P) for NRC Generic Review."
- 2. Letter from A. Cutter, CP&L, to NRC, August 24, 1989, "Reque~t for License Amendment, Power Distribution Control."
- 3. R. B. Stout, XTG: A Two-Group Three Dimensional Reactor Simulator Utilizing Coarse Mesh Spacing (PWR Version), XN-CC-28, Exxon Nuclear Company, Richland, Washington 99352, January 1975.
- 4. M. Todosow, A. L. Aronson, D. J. Diamond, Axial Power Distribution Control Strategies for PWRs, BNL-NUREG-28797, Brookhaven National Laboratory, Upton, New York 11973, June 1980.
I I ~
ADVANCED NUCLEAR FUELS CORPORATION ANF-88-054(NP)(A)
Issue Date: 3/22/89 PDC-3: ADVANCED NUCLEAR FUELS CORPORATION POWER DISTRIBUTION CONTROL FOR PRESSURIZED WATER REACTORS AND APPLICATION OF PDC-3 TOH. B. ROBINSON UNIT 2
. Prepared by:
3-/}-S'7'
- ton O'Leary, Team der PWR Neutronic Neutronics and Fuel Management .
Fuel Engineering and Technical Services March 1989 scg
CUSTOMER DISCLAIMER IMPORTANT NOT1C2 REGARDING CONTENTS AND USE OF THIS DOCUMENT PUASI! READ CAREFULLY Aavancad Nuclear Fuels Corporation's warranties and reQresentauons con-cerning tt,e subject matter of tnis document are tnose set tortn 1n rne Agreement belWNn Advanced Nuclear Fuels Corporation and tne Customer pursuant to wnicn tt,is dCCument is issued. Acccn:lingty, excac,t as otnerw1se expressly pro-vided in such Agreement,* nertner Advane8C1 Nuclear Fuels Cor;iorat1on nor any parson acting on its behalf makes any warranty or reorasentation, excressed or implied, with resi:iect to tne accuracy, completeness, or userulness of tne infor-malicn c:cntainec:I in tnis dccument, or tnat tne use of any information. apparatus.
matt,oa or process disclosed in tnis dOclJment w1H not infringe pnvately owned ligtltlr. or assumes any liabilities w i t h ~ to tne use of any information. ao-parmua. mecnod or procea disdos9d in tnis document.
The intarmalicn containec:I herein iS tor tt,e sot* use of Customer.
In ards ta avoid imi,airment ot rights ot Advancaa Nuelear Fue,s Corporation* ,n patenta or inventions wtiicn may be induded in tne information contained in this
- dccwTlent. tt,e rec:i;:lient, by its ~ance of tnis *documem. agrees not to pwitish or make puatic use (in tne patent use of the term) of sucn information until so auttlerized in writing by AdVancad Nuclear Fuets Corporation or until attar six (8) months following termination or expiration of :n1.-aforesaid Agreement and any extensien tnerect, unless otnerwtH excressly provided in 1ne Agreement. No**
rights or licenses in or to any patents are implied cy tne tum,sn,ng of this docu-ment.
ANF-3145.472A (12/87)
\ '
1)
)
-i- AN F-88-054(N P) (A)
TABLE OF CONTENTS
1.0 INTRODUCTION
SUMMARY
I 2.. 0 VERIFICATION 4 2.1 Introduction 4 2.2 Description of the POC-1 and PDC-2 4 2.3 Description of the PDC-3 5 2.4 Description of the PDC-3 6 2.5 Poc..:2 Results ..... 7 3.0 GENERIC POC-3 METHODOLOGY. 15 3.1 Introduction .. ..... 15 3.2 D~scription of Reactor Operating Modes Analyzed .. 15 4.0 POC-3 METHODOLOGY APPLIED TO H.B. ROBINSON UNIT 2 24 4 .1 Introduction . . . . . . . . . . 24 4.2 H.B. Robinson Unit 2 Plant Characteristics and Model Development 24 4.3 V(Z} Distribution for +/-5% Target Axial Offset Band 25 4.4 V(Z} Distribution for +/-3% Target A~ial Offset Band 26 4.5 Operation. Outside the Target Band . . . . . 27 4.6 Implementation of POC-3 Procedures for H.B. Robinson Unit 2 29
5.0 REFERENCES
. . . . . . 49
'l
~;; - ANF-88-054(NP) (A)
LIST OF TABLES Table 2.l POC-3 nsamplen Plant Versus POC-2 nGeneric" Plant Character-istics . . . . . . . . . . . . . . . . . . . 11 2.2 POC-2 Reactor Operating Conditions Analyzed, t5% Target Band 12 3.1 PDC-3 Versus POC-2 Reactor Operating Conditions Analyzed (BOC and EOC) . " . . . . * . . . . . . * . . . e * * * * . * * * * * * * *
- 20
-iii- ANF-88-054(NP) (A)
LIST OF FIGURES Figure 2.1 Comparison Distributions . . . . Core Average Axial Power
. . 13 Comparison POC-2 VZ(Z) Distributions:
+/-51 Target Band .... . ..
'
- 14 3.1 5 Day 3-6-3-12 Load Follow Cycle. 21 3.2 +/-5% Target.Axial Offset Band * *
- 0 22 Comparisons POC-3 VZ(Z) Distribu-tions: +/-5% Target Band .* . 23 4.1
- H.B. Robinson Cycle 12 *Calculated POC-3 V(Z) Distribution: :t5%
Target Band . . . . . . . . . . . . . . . . .* o * " * * * * *
- 31 4.2 Comparison of H.B. Robinson CycJe 8 and nsamplen Plant Calculated POC-3 VZ(Z) Distributions: +/-5% Target Band . . . . . . . . . . . 32 4.3 Comparison of H.B. Robinson Cycle 12 and Cycle 8 Calculated PDC-3 V(Z) Distributions: +/-5% Target Band . : . ; .. . . . . . . 33 4.4"' Effect of Control Rod Worth on H.B. Robinson Cycle 12 Calculated POC-3 V(Z) Distribution: +/-5% Target Band . . . *. . . . . . . 34 4.5~ Cilculated Composite V(Z) Distribution and Limiting POC-3 V(Z)
Distribution:. +/-5% Target Band . . . . . . . . . . . . ~ . 35 4.6 limiting PDC-3 V(Z) Distribution Versus Current Pbc-f'V(Z)
Di stri but ion: :t5% T~rget Band . . . . . . ., . . . . . . . 36 4.7
- H.B. Robinson Cycle 12 Calculated POC-3 V(ZJ Distribution: :t3%
Target Band . . . . . . . . . . . . . . . . . . . . 37 4.8 Effect of Control Rod Worth on H.B. Robinson Cycle 12 Calculated POC-3 V(Z) Distribution: t3% Target Band . . . . . . . . . 38 4.9 Calculated Composite V(Z) Distribution and Limiting PDC-3 V(Z)
Distribution: +/-3% T~rget Band . . . . . . . . . . . . . 39 4.10 Limiting POC-3 V(Z) Distribution Versus Current PDC-2 V(Z)
Distribution: +/-3% Target Band. . . . . . . . . . .
- 40 4.11 V-Factor Versus Delta AO, 50%-Power, +/-5% Target Band . . . 41
..* ~
-iv- ANF-88-054(N P) (A)
- usr OF FIGURES Figure Page 4.12 V-Factor Versus Delta .AO, 7~ Power, +/-Si Target Band . ' . 42 4.13 V-Factor Versus Delta AO, 9~ Power, +/-5~ Target Band 43 4.14 V-Factor Versus Delta AO, 5°" Power, +/-3" Target Band 44 4.15 V-Factor Versus Delta AO, 70" Power, +/-3" Target Band . 45 4.16 V-Factor Versus Delta AO, 9~ Power, +/-3i Target Band 46 4.17 Allowable Deviation From Target Flux Difference . . . 47 4.18 Limiting PCC-3 V(Z) Distributions for +/-5% and +/-3i Target Bands .. 48
ANF-88-054(NP)(A)
POC-3: ADVANCED NUCLEAR FUELS CORPORATION POWER DISTRIBUTION CONTROL FOR PRESSURIZED WATER REACTORS AND APPLICATION OF POC-3 TO H.B. ROBINSON UNIT .2
- 1. 0 INTRODUCTION AND
SUMMARY
Advanced Nuclear Fuels (ANF} reactor power distribution control (POC) procedures have prevfously been presented in . References l through 3.
Reference 1 describes a procedure denoted POC-1. Reference 2 describes a procedure denoted POC-2. Reference 3 provides additional information with respect to PDC-2. This report presents an extended Poc.:.2 methodology, henceforth referred to as PDC-3. PDC-3 was developed to pro vi de justification for a less limiting V(Z} distribution through the use of a more conservative analysis. The more conservative analysis allows the final V(Z) distribution to be drawn closer to the calculated distribution .. A descrip-tion of the PDC methodology .and associated terminology is presented below.
The basic concept of the PDC procedures is to control the variation in the core power distribution during reactor operation by contfolling the variation in the core power axial offset. The* core power a.xi al offset (AO) is .defined as:
AO '"'
where, Pr '"' Power in MWth in the top half of the core
- Pg '"' Power in MWth in the bottom half of the core
ANF-88-054(NP) (A)
Thus, the axial offset is the difference in power between the top and bottom halves of the core expressed as a fraction ( or percentage) of the
- total core P.ower. The above definition may be rewritten as f o11 ows:
Ir - Ie AO
- Ir+ Ie
- where, Ir
- Pr/Po Ie
- Pa/Po AI
- Ir - Ie
- F1ux difference Po
- Rated reactor.power (MWth)
P
- Operating reactor power (MWth)
Under POC procedures, a target axial off set is determined at fu 11 power, equilibrium conditions. The al1owed axial offset (or U) variation about the target axial offset is called the target axial offset (or ii!} band.
The major feature of the POC-2 procedure is the V(Z) distribution .. The V(Z) distribution is the ratio of the maximum anticipated increase- in FqT(z),
total peaking by plane, during non-equilibrium operation when following POC-2 procedures, to FQT(z) corresponding to the target axial offset. POC-2 V(Z) di stri but ions associated with :t5% and :t31. target axial offset bands '"'ere developed in References 2 and 3, respectively. The approved POC-2 methodology is characterized by six load follow simulations which are used to establi.sh the maximum anticipated increases in FqT(z). The load follow simulations utilize a. one-dimensional (10) XTG model which describes core average axial behavior. Radial behavior is represented by conservative radial factors, Fxy*
This report presents the POC-3 methodology, which differs from the current POC-2 methodology in the generation of the V(Z) distribution. The
ANF-88-054(NP)(A) generation of the POC-! V(Z) distribution is characterized by the following:
The "generic" POC-3 methodology, characterized by the specific set of load foi'low simulations used to generate a POC-3 V(Z) distribution, is presented in Section 3.0.
The POC-3 methodology was applied to H.8. Robinson Unit 2 Cycle 12 in order* to generate V{Z) distributions for +/-5% and +/-3% target a.xi al offset
. bands. The results of this appl-ication and the limitations on its use are presented in Section 4.0.
ANF-88-054(NP) (A)
/I 2.0 VERIFICATION OF 2.1 Introduction The advantages of a *methodology* are 2.2 Description of the POC-1 and POC-2 The principal tool used in POC-1 and POC-2 is The calculational model of a typical PWR reload cycle is set up Centro 1 rods are represented as add it; on s at an absorber cross section, a delta cross section, in those assemblies where rods are inserted. Core boundary cond it i ans are described
ANF-88-054(NP) (A)
This model is then depleted The macroscopic cross section tables as a function of burnup are constructed The axial plane burnup is obtained in a completely analogous manner. For a reload core In Reference 1, model was verified _by comparisons against reactor measurements (slow transient tests and a xenon buildup f o11 owing shutdown experiment}. As a result of these comparisons, 2.3 Descriptinn of the POC-3 The "sample" *- model utilized the develo*pment of the "generic" .POC-3 methodology Westinghouse type plant for which ANF has fuel management responsibilities. This model was generated using standard ANF PWR neutronics methodology . (S- 9) for utilization in standard reload design calculations and has been benchmarked against many eye l es of operating data. The adjustments
ANF-88-054(NP) (A)
The model was depleted I
2.4 Description of the POC-3 j For the POC-3 I
.J discussed in Section 2.3.
The model was depleted to
AN F-88-054(N P} (A}
2.5 POC-2 Results with the Models In Reference 3, the use of was established. These are described in detail in Section 3.2.
The V{Z) distribution represents the maximum increase in the equilibrium FQT(z) distribution, at each axial plane Z, which may occur when a reactor is operated in accordance with POC procedures. For each case ana]yzed, a V{Z) distribution is determined as the ratio of the maximum FQT(z) which occurs .'during the reactor operation
- simulation to the equilibrium FoT(z) distribution associated with the target axial offset.
The total peaking factor d~stribution, FqT(z), is calculated as:
FQT{z) ,. Fz(Z)
- Fxy(Z}
- Ftotal
- where, FQT(z) .
- Total peaking factor at axial location Z Fz(Z} . Relative power at axial location Z Fxy(Z} . Peak radial at axial location Z Ftotal
. All required uncertainties, biases, and engineering factors In POC-2, Fq T(Z) ; s determined The core a"'.erage axial distribution, Fz(Z}, is obtained The radial component, Fxy(Z),
AN F-88-054(N P) (A)
Fz{Z)
- Fxy{Z)
- FQN{z), as wel 1 as each component, The V{Z) distribution is then calculated as:
The V(Z) distribution i.e.
By studying the axial component of the V(Z) distribution, VZ(Z) represents the maximum increase in the equilibrium Fz(Z) distribution, at each axial plane Z, which may occur when a react6r is operated in accordance with PCC procedures. For each case analyzed, a VZ(Z) distribution is determined as the ratio o.f the maximum. Fz(Z) which occurs during the reactor operation simulation to the equilibrium Fz(Z) distribution
ANF-88-054(NP) (A) as~oci ated with the taraet axi a1 offset.
The raa; a 1 component of the V(Z) di stri but ion is The VZCZ} curves qenerated are compared in Figure 2.2.
As shown, Small differences between the two curves are due The lack of sensitivity of the results to
ANF-88-054(NP) (A}
to this oarameter was studied. The lack of sensitivity Differences in the Doppler broadening coefficient, These results demonstrate models are
. for defininn V{Z) disi:.ributions. Differences in V{Z) distributions generated
l~-
1 ANF-88-054(NP)(A)
TABLE 2.1 POC-3 "SAMPLE" PLANT VERSUS POC-2 "GENERIC" PLANT CHARACTERISTICS PDC-3 PDC-2 Power Density - 104.5 kW/liter 100 kW/liter Nominal Enrichment 3.25 w/o 3.0 w/o Active Fuel Height 12 ft. 12 ft.
Coolant Fl ow Rate 1.119
- 108 lb/hr 1. 43
- 108 1b/hr (3 loop) (4 1oop)
Inlet Temperature 54&.s*F 545.F Single Control Bank Worth lr. Ap 1% Ap
ANF-88-054{NP) {A)
TABLE 2.2 POC-2 REACTOR OPERATING CONDITIONS ANALYZED, +/-5% TARGET BAND
- 1. 5 ----.---..--r--.--.---r---.r--.--~-,--..----,r--r---.-~--,--~-,---,r--,---.-,---,---,
DOC n:: 1.0
---.---------- EOC w
31:
a n..
w l-
_J I
w w I n::
- o. 5
)>
0.01----L---£--L-~-L-.--L---1~-L-..,......L--L-.~-L----L---1-J.---L~.&--~----------1------------ z""Tl 0 l 2 3 5 6 7 e 9 JO 11 12 I CX>
CX>
CORE HEIGHT CFT> 0 U1 I
~
z FIGURE 2.1 CALCULATED CORE AVERAGE AXIAL POWER DISTRIBUTIONS
~
""U
~
I I
)>
,,z I
CX>
coI 0
en
+:>,.
f I GUI{[ 2". 2 COHPAR I SON z
_:g CALflJLArfll PDC-2 VZ(Z) DISTRIBUTIONS: t5% TAIUiET BAND ~
ANF-88-054(NP) (A) 3.0 GENERIC POC-3 METHODOLOGY 3.;i Introduction Based upon the results of earlier POC-2 analyses( 2, 3 ),
An expanded set has been developed which produces results The V(Z*) distribution _developed from this expanded analysis, henceforth referred to as the POC-3 V(Z) distribution, is bounding, and additional margin is not required.
It should be noted that POC-3 operating proce~ures are analogous to POC-2 operating procedures for a given target band. Jhe only differences are 3.2 Description of Reactor Operating Modes Analyzed The set of load follow cases developed for the POC-3 methodology are In Reference 2, the sensitivity of the V(Z) distrib~tion to many parameters was studied in detail.
ANF-88-054(NP) (A)
The reactor op~rating modes which were considered are characterized by load follow operation. Load follow operation implies thaf the reactor is cycling from one power level to another in a reaular oattern. Fiaure 3.1 shows the tvoP. nf power cycling considered, In this cycling scheme, the reactor power ihis is the same basic structure as utilized in previous PDC analyses< 1* 3 ).
In PDC procedures, the plant is required to operate within a given target band about a target axial offset. This operating range is illustrated in Figure 3.2 for a +/-5% target axial offset band. The operating modes the extremes of operation within this operating range. They are to be evaluated at both The operating modes are:
ANF-88-054(NP)(A)
The need for became apparent in the application of POC-3 to the H.B. Robinson Unit 2 Cycle 12 blanketed core (see Section 4.0). In a blanketed core, xenon oscillations are more difficult to initiate and the The HF .A case was included as a corollary to this argument.
In the PDC-2 methodology, the set of load follow cases considered are
ANF-88-054(NP)(A)
The operating conditions analyzed in the PDC-2 and PDC-3 methodologies are listed in Table 3, 1.
The PDC-3 V{Z) distribution is generated The V{Z) distribution derived trom tnese cases is therefore also bounding. Actual plant operation would result in smaller variations in FQT(z) since it is unlikely that the plant would operate continuously near the edge of the allowed operating band.
The +/-5~ target band VZ(Z) distribution, The PDC-3 methodology results in a VZ(Z) distribution An increase in operating margin will be derived from the use of the V(Z) based on the POC-3 methodology sine~ provides the justification for drawing a less 1 imiting V(Z) over the region of the core where the axial power distribution peaks occur.
- As discussed in Section 2.5, dI values of up ta occurred during the simulations.
ANF-88-054(NP) (A)
This is due to the fact that axial region where is the region between the core edge and the point where the a.xi a I peak occurs.
ANF-88-054(NP)(A)
TABLE 3.1 POC-3 VERSUS POC-2 REACTOR OPERATING CONDITIONS ANALYZED (BOC ANO EOC)
- These cases are described in detail in Section 3.2.
I I'\)
I FIGURE 3.1 5 DAY 3-6-3-12 LOAD FOLLOW CYCLE
- ANF-88-054(NP) (A)
I I
I
.I 100 a::
LIJ
- a C
ii. 80
...J a::
I.I.I Q
I.I.I .
CZ:
'~
....z
.I.I.I c.J CZ:
I.I.I ii.
a ___________....__ __.___,,___________...__"---...1
-so an 10 o 10 2D 30 40 50 DELTA AO CD FIGURE 3.2 +/-5% TARGET AXIAL OFFSET BAND
I
~
l.AJ I
tlbUKt J.J COMPARISON OF 30 ANO 10 XTG CALCULATED POC-3 VZ(Z) DISTRIBUTIONS: t5% TAl!GET BAND
ANF-88-054(NP) (A)
'4.0 POC-3 METHODOLOGY APPLIED TO H.B. ROBINSON UNIT 2 4.1 Introduction The PDC-3 methodology discussed in Section 3.0 has been applied to H.B.
Robinson Unit 2 (HBR2) Cycle 12. Pl~nt characteristics of HBR2 are discussed in S~ction 4.2. Also discussed in Section 4.2 is the model used for the HBR2 POC-3 analyses. The POC-3 results for t5% and t3% target axial offset bands are presented in Sections 4.3 and 4.4, respectively. The development of axial offset limits for operation outside the target bands is discussed in Section 4.5. The implementation of the V(Z} distributions developed in Sections 4.3 and 4.4 is discussed in Section 4.6.
4.2 H.B. Robinson Unit 2 Plant Characteristics and Model Development Several HBR2 p1ant characteristics differ from c:haracteri st; cs of the POC-3 "sample" plant described in section 2.0:
- 1) In HBR2, the nominal power density is 86.6 kW/liter as compared to 104.5 kW/liter for the POC-3 "sample" plant.
2} The leading control bank (Bank D) worth in HBR2 is less than 1% AP= 1000
-pcm. The worth has generally varied between 600 and 800 pcm in Cycles 8 through 12.
- 3) Beginning in Cycle 10, the fuel loaded into HBR2 has contained natural uranium axial blankets (NUABs} in the top and bottom 6 inches of active core height. In Cycle 12 all fuel except for 8 twice-burnt assemblies (out of 157) contain NUABs.
- The model used for' the HBR2 POC-3 analyses is the model developed using standard ANF PWR neutronics methodology (5- 9) in and has been benchmarked against several cycles of operating data. Unlike the analyses performed with the PDC-3 "sample" model, the HBR2 analyses will
ANF-88-054(NP)(A) 4.3 V(Z) Distribution for +/-5% Target Axial Offset Band The POC-3 methodology discussed in Section 3.0 was applied to HBR2 .Cycle 12 using the model dis~ussed in Section 4.2 for a +/-5% target axial offset band. The calculated V(Z) distribution generated is presented in Figure 4.1. Of these 1 V{Z) va 1ues. Each of the three HBR2 p1ant characteristics mentioned in Section 4.2 (power density, rod warth, axial blankets) affects the shape and magnitude of the HBR2 V(Z) distribution.
The effects of power density and axial blankets were analyzed by applying the-'POC-3 methodology to HBR2Cycle 8 for a +/-5% target band.
- 1) The effect of the *reduced power density can. be 'seen from a comparison of the VZ(Z) distributions for the POC-3 "samcle" olant. and HBR2 Cycle 8 shown in Fiaure 4.2.
2} The effect of the blankets can be seen, from a comparison of the V( Z)
, distributions for HBR2 Cycle 8 and HBR2 Cycle 12 shown in Figure 4.3.
The effect of control. rod worth on the HBR2 Cycle 12 V(Z) di.stribution
- was studied
- As discussed in Section 2.5, AI values slightly larger than occurred during thi simulations.
ANF-88-054(NP) (A)
The ranae of control rod worths studied results in V{Z) distributions varying by Since the control rod worth of HBR2 Cycle 8 is less than that of the POC-3 "sample" plant and since the control rod worth of HBR2 Cycle 12 is 1ess than that of HBR2 Cycle 8, the differences observed in Figures 4.2 and 4.3 may be partially influenced by control rod worth effects.
At each axial level Z, the maximum of the V(Z) distributions in Figure 4.4 was used to generate a composite V(Z) distribution. In Figure 4.5, a limiting V(Z) distribution which bounds the composite V(Z} distribution is provided. This 1 imiting V(Z} distribution is applicable to blanketed HBR2 cores with ~ank D worths bounded by those studied above. A comparison of the PDC-3 V(Z) distribution and the POC-2 V{Z) distribution for the :t5% target band ls shown in Figure 4.6.
4.4 V{Z) Distribution for +/-3~ Target Axial Offset Band The POC-3 methodology discussed in Section *3,0 was applied to HBR2 Cycle 12 using the mode*, discussed in *section 4.2 for a :t3% target axial offset band. The calculated V{Z} distribution generated The effect of control rod worth o~ the :t3% target band V(Z) distribution was studied
- As discussed in Section 2.5, d! values slightly larger than occurred during the simulations.
ANF-88-054(NP) (A)
At each axial level Z, the maximum of the V(Z) distributions in _Figure 4.~i: was used to generate a composite V(Z) distribution. In Figure 4.9, a limiting V(Z) distribution, which bounds the composite V(Z) distribution is providea.
This limiting V(Z) distribution is applicable to blanketed HBR2 cores with Bank a worths bounded by those studied above. A comparison of the PDC-3 V(Z) distribution and the .PDC-2 :V(Z)* di.stribution for the +/-3% tar.get band is shown in ~igure 4.10.
4.5. Operation Outside the Target Band In calculating case specific V(Z) distributions (see Section 2.5), FTq(Z)
. is multiplied by the relative power level to account for the increase in Technical Specification limits on FTq(Z) due to a power level decrease. It was found that the maximum calculated V(Z) distribution (for both the !3%.and
+/-5% target band cases) was never limited by reduced power cases, i.e. the increase in the Technical Specification limits on FqT(z) due to a power level decrease was always larger than the in.crease in FQT(z) due to a power level decrease when operating within the target band. As a result, operation at axial offsets outside the target band is allowed below 90% power for periods not to exceed 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> in any consecutive 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> oeriod. The time outside the band is restricted A11 owing the ax1a1 OTTse~ to Ce outside the target band for short periods of time provides necessary flexibility in plant operation.
Operation outside the target bands is allowed during these short periods to the extent that resultant V(Z) distributions are expected to be bounded by the maximum V(Z) distribution. *Since the maximum V(Z) distribution
ANF-88-054(NP)(A)
The maximum calculated V(Z) distributions, i.e. the composite* V(Z) distributions discussed in Sections 4.3 and 4.4 for t5% and t3% target bands.
respectively, were used The limits on operation outside the target band are determined from the relationship between V-factors and 4AO (* axial offset*- target axial offset) for a given pqwer level. In order to establish this relationship The positive and negative 4AO values allowed at a particular power level, as described above, were converted to positive and negative iiI
ANF-88-054(NP)(A)
The limits on operation outside the +/-Ji target band were chosen such that the limits in terms of flux difference would be levels.. The value of 2% was chosen since this is the difference between the The restrictions on operation outside the target band are shown in Figure 4.17 for both the +/-5~ and +/-Ji 4I target bands.
4.6 Implementation of POC-3 Procedures for H.B. Robinson Unit 2 The implementation of POC-3 operating procedures is identical to the implementation of POC-2 operating procedures. The differences are in the actual V{Z) distributions to be used and in the axial offset limits *during operation outside the target bands. These were discussed in detail in Sections 4.3, 4.4, and 4.5. Replacement. figures for the current HBR2 Technical Specification Figures 3.10-4 and 3.10-5 are shown in Figures 4.18 and 4.17, respectively.
In order to apply the V{Z) distributions developed in Sections 4.3 and 4.4 to a given HBR2 cycle, two core configuration characteristics to which V{Z) is sensitive need to be verified. Specifically:
- 1) The core must be primarily composed of natural uranium blankets (NUABs) at the top and bottom 6 inches of active core height, and
- 2) The Bank D worth must be bounded by the worths considered in Sections 4.3 and 4.4.
I
ANF-88-054(NP) (A)
In Cycle 12, eight twice-burnt assemblies did not have NUABs. The balance of the assemblies were fully blanketed. Consequently, it is recommended that this bound on the number and type (i.e. twice-burnt) of non-blanketed assemblies be *verified in the Safety Ana 1ysi s
- Report for* each eye le where Figures 4.17 and 4.18 are to be applied.
In the Cycle 12 . analyses, the standard Bank O worth at the HFP rod insertion limit of 114 steps was calculated to be 418 pcm at 500 MWd/MTU, HFP,
.equilibrium, xenon .conditions. It was found that increasing control rod worth generally increased V(Z) distributions, and Bank O worths as high as were considered in the generation of the V(Z) distributions. Consequently, it is recommended that this bound on the Bank O worth (at the above conditio.ns) be verified in the Safety Analysis Report for each cycle where Figures 4.17 and 4.18 are to be applied.
I w
~
I
)>
,,z I
(X)
CORE HEIGHT <FT) (X) 0 I
en
.i:,.
z HGUllE 4 .. 1 11.B. ROBINSON CYCLE 12 CAl.CUl.AHD PDC-3 V(Z) DISTRIBUTION: t5% TARGET BAND
. "'O
~
I t,.)
~
I
~ORE HEIGHT <FT>
FIGURE 4.2 COMPARISON OF 11.0. RODINSON CYCLE 8 ANO "SAMPLE" PLANT CALCULATED POC-3 VZ(Z) DISTRIBUTIONS: !5% TARGET DANO
I w
w I
}>
z "Tl I
CORE HEIGHT CFT> ())
())
I 0
en
.i:,.
z FIGURE 4.3 COMPAIUSON OF 11.B. ROBINSON CYCLE 12 ANO CYCLE 8 CALCULATED PUC-3 V(Z) DISTRIBUTIONS: t5% TARGET DANO -
~
"U
)>
z "Tl I
OJ CORE HEIGHT <FT> OJ 0
I 01
~
z FIGURE 4.4 EFFECT OF CONTROL ROD WORTH ON H.* 8. RODINSON CYCLE 12 CALCULATED PDC-3 V(Z) DISTRIBUTION: t5% TARGET BAND
""O
~
_J
I w
U1
- I
)>
z
'Tl (X)
CORE HEIGHT <FT> (X) 6 01
~
z FIGURE 4. 5 CAtCUIATED COMPOSITE V(Z) DISTRIBUTION ANO LIMITING POC-3 V(Z) DISTRIBUTION: t5% TARGET BAND -
"U
~
~~~ POC-3 V<Z>
- - - - POC-2 V<Z>
J. J5
/
(11. 25, 1.15
/
/
/
/
/
/
____ 1_.6..._._l.J_Il ___ ~ ________________<!: ~:...!.:.1.!J,,,,""' (10. 4
- 1.11) t!
J. JO I
w 0\
I (3.8, 1.07
). 05 J. 00 ,.__+-___._....__---&.._...___..__..._______--&--..JL--...J....--l~-&----1--L---&-..1-~-..1---&.--L---L----I )>
0 l 2 3 z
5 6 7 8 9 JO I) 12 "Tl I
CX>
CORE HE i GHT CFT> CX>
0 I
01 z_::g FIGURE* 4.6 LIMITING PDC-3 V(Z) DISTRIBUTION vrnsus cu,rnrnr PUC-2 V(Z) DISTIUDUTION: +/-5% TARGET BAND ~
I w
I
)>
z "TI I
CX)
, CX)
I 0
01
~
z FIGURE 4.7 11.8. ROBINSON CYCLE 12 CALCULATED PDC-3 V(Z) DISTRIBUTION: t3% TARGET BAND "U
~
I w
00 I
)>
,,z I
OJ CORE HEIGHT CFT) OJ 6
01
.i:,.
z "U
FIGURE 4.8 EFFECT OF CONTROL ROD WORTH ON H.B. RODINSON CYCLE 12 CALCULATED PllC-3 V(Z) DISTRIBUTION: :t3% TARGET DANO
_j
I w
40
)>
z"Tl CORE HE lGHT <FT) co co I
I 0
FIGURE 4. 9 CAI CUtATE.D COMPOSITE V(Z) DISTRIBUTION ANO LIMITING -PDC-1 V(Z) DISTRIBUTION: t3% TARGET BAND
-z01
.i:,.
_:g
~
i, ~c ..--.----.------.----..-------..--.--..--..-----,...--.----r-,----r-r--r----....--.----r-,----r-,
- - ~ POC-3 V<Z)
- - - - POC-2 V(Z)
). 15 (11.25. 1.12)
/*
/
/
" 1.10
~ /
/
/
> /
~~~~~~/
- - - - - ( 1 . 8 . 1.075) 1.085) 0 I
.Ja I
). 05 (3.4. l.0525) (8.0. l.0525)
)>
~)O z "Tl 0 I 2 3 4 5 8 7 8 9 10 II )2 OJ I
OJ CORE HEIGHT <FT> 0 01 I
.l>,
z.J!
FIGUlff 4 .10 l.lMITING PDC-3 V(Z) DISTRIBUTION VERSUS CUIWENl PDC-2 V(Z) OISllUDUTION: t3% TARGET DANO *-
~
I
.f:,,
I
)>
DELTA AO
,,z I
Ol OlI 0
01 FIGURE 4.11 V-FACTOR VERSUS DELTA AO, 50% POWER, t5% TARGET DANO z........
"U
~
~
N I
)>
z "Tl I
CX>
CX>
DELTA AO 6 01
~
z FIGURE 4.12 V-FACTOR VERSUS DELTA AO, 70% POWER, 151 TARGET BAND -
~
"'U
w I
)>
,,z DELTA AO I CX>
0)
I 0
01
.i,.
FIGURE 4.13 V-FACTOR VERSUS DELTA AO, 90% POWER, i5% TARGET DANO z_::g
~
1-1::a I
)>
,,z I
DELTA AO O>
O>
6 01
~
z FIGURE 4.14 V-FACTOR VERSUS DELTA AO, 50% POWER, i3% TARGET DANO
~
"'U
I
-~
l1l I
)>
z "Tl DELTA AO I CX>
CX>
I 0
01
~
FIGURE 4.15 V-FACTOR VERSUS DELTA AO, 70% POWER, i3% TARGET BAND z~
~
I
.i,..
0\
I
)>
z "Tl co DELTA AO (X>
0 I
01 z-u FIGURE 4.16 V-FACTOR VERSUS DELTA AO, 90% POWER, tl% TARGET BAND -~
120 - - - - - - - - - - - - - - - - - - - - - -.........---.-...--....-,,.......-.----......... -----r-,
0:::
w 100
~
0 (+10, 90) n..
/ ( -6. 90) ( +8, 90 ) ,
_J
~ BO /
/
0:::
.w "/
/
- c t- ./
/
/
Cl w
t-60 /
/
0:::. (-24, 50)
/.
/
~ (-22. 50)
(+28. 50)' (+30, 50) ~
I lJ.. ......
a t- 40 z +/- 5% TARGET DANO w ---- +/- 3% TARGET DANO LI a::
w o._
20 0 L--&_ _ _ _ _ ..__.---L__.__..._.....__~-.&.----_.__..&-.L-A---L__.__..._...._L--a---L__.__..._~~-------...._._..---L_____, )>
-40 -30 -20 -10 0 10 20 30 z "Tl I
DEVIATION FROM TARGET FLUX DIFFERENCE (%) O>
0) 0 I
01
.i:.
z-u f IGURE 4.17 ALLOWABLE DEVIATION FROM TARGET FLUX DIFFERENCE
-~
+/- 5% TARGET BAND
+/- 3% TARGET BAND I. 15
- I---.___~
(1.6, 1.11} (10.4, 1.11
~ I. ID
( 10. 6 / L..Qfilij__ _
I
____ {.!:.!!,. 1.075) . . .i,.
co
', ' , (3.8, 1.07) (7 .6, 1.07} _,,.,,,;
/
I
' . ' /
- 1. 05 '-----------------~/
(3.4, 1.0525) (8.0, 1.0525) l.00'---'----'~-L---L--.£---L~L----L.~L-..-L___.L-.-L..---JL--.J---1---&---&--..&----L--..&---&.--...__..____. }>
0 l 2 3 4 5 6 7 B 9 10 11 12
,,z I
(X)
CORE HEIGHT <FT) (X)
.i:,.
z f IGUnE 4.18 LIMITING PDC-3 V(Z) DISTlllDUTIONS FOR t5% AND t3% TAHGET BANOS -
"'U
~
ANF-88-054(NP)(A)
5.0 REFERENCES
- 1. J.S. Holm and F.B. Skogen, nExxon Nuclear Power Distribution Control for Pressurized Water Reactors n, XN-76-40 (A) , Exxon Nuc 1ear Company, Richland, Washington 99352, September 1976.
- 2. J.S. Holm and R.J. Burnside, "Exxon Nuclear Power Distribution Control for pressurized Water Reactors Phase !In, XN-NF-77-57 and XN-NF-77-57 Supplement 1 (A), Exxon Nuclear Campany, Richland, Washington 99352, May 1981.
- 3. J.S. Holm, "Exxon Nuclear Power Distribution Control for Pressurized Water Reactors Phase Iln, XN-NF-77-57 Supplement 2(A) and XN-NF-77-57 Supplement 2 Addendum 1 (A), Exxon Nuclear Company, Richland, Washington 99352, October 1982.
- 4. M. Todosow, A.L. Aronson, D.J. Oiamo.nd, nAxial Power Distribution Control Strategies for PWRsn, BNL-NUREG-28797, Brookhaven National Laboratory, Upton, New York 11973, June 1980.
- 5. R.B. Stout, "XTG: A Two-Group Three Dimensional Reactor Simu~ator Utilizing Coarse Mesh Spacing {PWR Version}n, XN-CC-28, Exxon Nuclear Company, Richland, Washington 99352, January 1975.
- 6. XN-NF-75-27(A), "Exxon Nuclear Neutronics Design Methods for Pressurized Water Reactorsn, Exxon Nuclear Campany, Richland, Washington, 99352, June 1915
- 7. XN-NF-75-27(A) "Exxon Nuclear Neutronics Design Methods for Pressurized Water Reactors", Supplement 1, Exxon Nuclear Company, Richland, Washington 99352, September 1976
- 8. XN-NF-75-27(A), nE,xxon Nuclear Neutronics Desian Methods for Pressurized Water Reactorsn, Supplement 2, Exxon Nuclear Company, Richland, Washington 99352, Oe~ember 1977.
- 9. XN-NF-75-27(A), nE,xxon Nuclear Neutronics Design Methods for Pressurized Water Reactorsn, Supplement 3, Exxon Nuclear Company, Richland, Washington 99352, November 1980.
ANF-88-054{NP) (A)
Issue Date: 10/26/90 PDC-3: ADVANCED NUCLEAR FUELS CORPORATION POWER DISTRIBUTION CONTROL FOR PRESSURIZED WATER REACTORS AND APPLICATION OF f:'DC-3 iO H.B. ROBINSON UNIT 2 Distribution RA Copeland/US NRC (15)