ML19211C275
| ML19211C275 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 12/28/1979 |
| From: | Erickson P Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8001110151 | |
| Download: ML19211C275 (9) | |
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[pn n%,h UNITED STATES j $ e j,g NUCLEAR REGUL'ATORY COMMISSION sCgf E
W ASHINGTON, D. C. 20555 7..,Dfj:/
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December 28, 1979 Docket No. 50-285 LICENSEE:
0MAHA PUBLIC POWER DISTRICT (OPPD)
FACILI'Y:
FORT CALHOUN
SUBJECT:
MINUTES OF DECEMBER ll,1979 MEETING TO DISCUSS SETPOINT METHODOLOGY FOR FORT CALHOUN, CYCLE 6 RELOAD AND PROPOSED POWER INCREASE The subject meeting was held in Omaha, Nebraska at the OPPD Engineering Office. Atter.dacs crc listed in Enclosure #1.
Enclosure #2 provides a list of questions that were discussed with EXXON and OPPD at the meeting. OPPD agreed to respond formally to these questions. Question #11 was deleted because the Power Dependent Insertion Limit (PDIL) will remain unchanged for Cycle 6.
Also, Question #27 was deleted because that information is provided in a topical report which has been submitted to the NRC.
In addition t9 responding to the questions of Enclosure #2, OPPD agreed to provide the equations used to calculate the DNBR (Departure from Nucleate Boiling Ratio) that is used in their XCOBRA Code. OPPD also agreed to provide a sample calculation of the thermal margin / low pressure trip equation to illustrate the calculational procedure they used.
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Peter B. Erickson, Project Manager Operating Reactors Branch #4 Division of Operating Reactors cc:
See other side of this page 1740 247 8001110 /
[
i MEETING
SUMMARY
DISTRIBUTION ORB #4 f...
fir. W. C. Jones Division Manager, Production Operations Omaha Public Power District 1623 Harney Street Onaha, Nebraska 68102 Docket File R. Reid NRC PDR V. Noonan L PDR P. Check ORB #4 Rdg G. Lainas NRR Rdg G. Knighton H. Denton Project Manager E. G. Case OELD OI&E(3)
D. Eisenhut R. Ingram R. Vollmer R. Fraley, ACRS (16)
W. Russell Program Support Branch B. Grimes TERA T. J. Carter J. R. Buchanan "
A. Schwencer Meeting Summary File D. Ziemann NRC Participants T. Ippolito RLobel W. Gammill BMorris L. Shao j"i Qh J. Miller
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Enclosure #1 DECEMBER 11, 1979 OPPD-FORT CALHOUN CYCLE 6 MEETING NRC OPPD Peter B. Erickson Kenneth J. Morris Richard Lobel B uce Hickle Bill Morris F. A. Thurtell R. L. Jaworski J. K. Gasper EXXON PICKARD, LOWE & GARRICK Larry A. Nielsen Thomas Robbins James N. Morgan Gerald Owsley CREIGHTON UNIVERSITY Thomas L. Krysinski A. H. Kirshen BATTELLE, NW Walter J. Apley Galen M. Hesson OMAHA, NEBRASKA Roger Carroll P. O. Box 283 I
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Enclosure #2 Question 1 List all operational m auver or conditions considered in generating axial power shapes. Also list the control rod configuration and burnup. Describe how the Xenon oscillations were in;uced.
Also describe whether the plant was base loaded or in a load follow configura-tion.
Give the power history assumed.
This information may be provided most efficiently in matrix form.
Justify that only these maneuvers need be considered for generating axial power shapes.
For Ft. Calhoun Cycle 6, how many axial power shapes were generated and how many were used in the set point analysis?
Question 2 For the axial power shapes in Question 1, describe the analytical methods used to calculate these shapes.
Provide the spatial noding schemes for each computer calculation and the size of the time steps used.
Describe how reactivity feedback effects were included.
Give the uncertainties and accom-panying statistical statement for the reactivity effects.
Justify these un-certainties.
How many energy groups are used in these calculations? Justify this number of energy groups.
Question 3 T
Describe in more detail the calculation of Fxy done to determine Fg discussed in section 4.1.1 XN-NF-507.
Describe the PDQ model and show how (and which) peaking factors from PDQ are used in XTG to determine F Also, show the xy.
XTG 3D modeling.
Into how many increments are the CEA insertions divided for the various Fxy calculations? How many energy groups are used in these calcu-lations? Justify using this number of energy groups.
Question 4 Discuss to what extent the projected (utility planned) power history is included in the set point analyses (e.g., depletion calculations).
Discuss the effect of a difference between projected power history and actual power history on the set points.
If this effect is considered, demonstrate with sensitivity studies for various control rod manuevers and changes in boration that power history effects are adequately considered.
Discuss the types of power manuevers assumed (e.g., base loaded, 100-50-100, etc.).
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. Question 5 Discuss the initialization of conditions for the beginning of a cycle for set point calculations.
i Question 6 i
(a) What critical heat flux correlation is used by Exxon in calculating i
j the SAFDL on DN3R.
1 (b) Describe how limitations in the range of the correlation (e.g., the 15% quality limitation of the W.3 correlation) are accommodated in this SAFDL.
(c) Provide the specific criteria used to prevent exceeding flow stability limits and provide the justification for these criteria.
KW (d) The fuel melting limit its given on page 10 of XN-NF-507 as 21 73 this number the result of an Exxon calculation? Justify the use oF,nis number for two different fuel designs (Combustion Engineering and Exxon).
What fuel melting temperature was assumed for this calculation?
i Question 7 Provide a complete description of the determination of the shape annealing factor, SAF, for rt. Calhoun.
Is the determination of this factor consistent
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with Exxon calculational methods?
Question 8 Provide the Exxon definition of rod shadowing.
Describe in detail the calcu-lations done to determine the adjustment to the core average axial shape index to account for rod shadowing effects.
Give the results for Ft. Calhoun Cycle 6.
Will these results change from cycle to cycle?
Combustion Engineering performs rod shadowing calculations using neutron transport theory (CENPD 199, Section 2.1.1.4.1).
It appears that Exxon relies on diffusion theory. Justify this difference. Also, explain how uncertainties in this calculation are taken into account.
Show the calculational models used to perform these calculations.
Discuss the effects of transients which change CEA position on rod shadowing factors.
How is this effect included in the set point calculations?
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Question 9 For the uncertainty values listed on page 15 of XN-NF-507, justify the value listed.
List any experiments used te obtain these values and give a full description of the calculations done to obtain these uncertainties from experimental results. Where values from previous cycles of operation are used, justify that these are appropriate for Exxon calculational methods.
If any of these uncertainties are composed of several components, list all components and justify all the component values.
For the trip overshoot, is this based on a transient analysis? Descrite the analysis methods used to derive this value.
For each uncertainty listed, give a statistical statement characterizing the confidence in this value.
For each uncertainty, show, in detail, how it is included in the set point analysis.
Question 10 Section 4.2.1 lists typical uncertainties included in the TM/LP analyses.
Explain in detail now each of these uncertainties are included in the set point calculations.
Define what effects are covered by instrument processing error.
Please state whether the depressurization transient uncertainty is the only adjustment to the TM/LP for transient effects.
See Question 17 Question 11 Describe in detail how the PDIL is determined and how it is included in the set point analysis. What calculational methods are used?
Provide a comparison of calculated radial peaking factors with measured peaks at a given CEA position.
Question 12 How is flux tilt included in set point calculations?
Question 13 Will Exxon design of CE set points affect the Variable Overpower Trip Setooint?
If so, describe how Exxon designs this trip function.
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Question 14 (a)
Describe how the scram reactivity is included in the set point calculations.
List each application of this item.
Describe how the scram reactivity is deter-mined.
(b) Describe or reference the Exxon modeling of CEA shutdown reactivity as a function of CEA position.
Question 15 Describe in detail and provide appropriate equations to show how the various peaking factors and hot channel factors are included in the various thermal hydraulics calculations for the TM/LP trip.
If this is done in the same way as other thermal hydraulics calculations and this information has already been provided to the staff, the reference is sufficient, Question 16 Describe the calculation of the saturation limit curves.
List any computer programs used for this calculation, if required. List all uncertainties included in the analyses and show how they are used.
Question 17 Describe how dynamic effects are accounted for in calculating the TM/LP trip.
What computer codes are used? What transients are analyzed to determine the dynamic term? How are plant conditions i,pitialized for the calculations to determine dynamic effects.
List the values included for RPS delays to control rod actuation. What core power shapes are assumed? What reactivity feedback mechanisms are included? What values of reactivity feedback coefficients are used? Justify these values.
Discuss the r.odeling of the core sensors which would measure core or loop conditions to assure adequate consideration of delays in system response.
Question 18 Is the core Da-Power calculator equation included in Exxon Set Point Calculations?
If it is, provide a description of the procedure used to calculate the coeffi-cients and give their values.
If it will not b2 changed when Exxon calculates set points, explain why this is acceptable in view of the fact that different analytical methods will be used by Exxon.
In particular, explain why this is acceptable for Ft. Calhoun, which is planning operation at a higher power level.
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-5 Question 19 Describe in detail the methods used by Exxon to incorporate into the set point calculations those transient events which require a low flow trip.
Explain how Exxon treats the equivalent of the Combustion Engineering concept of a Required Overpower Margin.
Question 20_
liscu'.s in detail the method used by Exxon to incorporate into the set point cal a!ations those transients which require no reactor trip.
List all the events considered in this category.
Explain the step-by-step procedure that is used to calculate the required protection.
Question 21 Provide a comparison of ENC set point calculations with those from a previous cycle of Ft. Calhoun as discussed on page 3 of XN-NF-507.
Explain the cause of any differences between the two calculations.
Question 22 Provide the curves of Pfdn and B0PM versus peripheral axial shape index for the CEA insertions used for the Ft. Calhoun Cycle 6 set point calculations.
Question 23 Describe in detail the method used to calculate the linear heat generation rate and DNB tents (such as Figures and in the Ft. Calhoun Technical Specifications).
Question 24 Section 6.2.3 of XN-NF-507 describes the method of calculating the equation fo r P The following questions refer to this procedure:
var.
(a)
Step (1) states that upon selecting a power, the APD offset trip defines the limiting axial shapes to be considered.
However, Step (4) states that only one adverse power distribution is selected.
How is this worst power distribution selected? Justify that there is no worst power distribution.
Provide the axial shape which is selected.
(b) Correct the wording of Step (7).
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. (c) Describe in detail how Step (8) is carried out.
Also, Step (8) refers to Figure 5.1.
Is this an error?
(d) h is calculated frem the equation o%c,
- 7\\nc u
T* i -E>
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by first selecting a oower then picking the values) lor, Furs, lm, lAu i
What values of Wy,, he u, *L,, Ta, are selected? The value of will change with the choice of these values.
Show that any choice of these values is acceptable if there is no specific method of selecting then. What is the advantage of selecting 6 in this manner over calculating 4 h f g
simultaneously? Which rethod is more conservative?
(e) Describe the step-ty-step procedure used to obtain the PF(B) function.
Show the relationship of this function to possible axial flux shapes.
(f) What check is made that t.1e resulting equation for P is conservative var at all possible conditiens.
(g) How is Fag included in this procedure?
Question 25 Discuss in detail how the design differences of different types of fuel bundles in a reload core are included in the set point calculations.
In particul ar, differences in fuel bundles manufactured by two different fuel vendors (e.g.,
Exxon and Combustion Engineering for the Ft. Calhoun Cycle 6 reload) should be addressed.
How does Exxon odel fuel bundles of another manufacturer.
Examples of possible areas of possible insufficient information are:
(1 ) fuel densification characteristics (2) fuel bundle flow distribution characteristics (3) fuel rod internal fill gas pressure Ouestion 26 Discuss protection provided by set points to asymmetric transients (such as those affecting only one stea" generator).
Cuestion 27 Provide a flow chart describing the sequence of calculations and the type of calculations done to calculate set points for a Combustion Engineering reactor.
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