ML20206D123
| ML20206D123 | |
| Person / Time | |
|---|---|
| Issue date: | 04/27/1999 |
| From: | Joshua Wilson NRC (Affiliation Not Assigned) |
| To: | Swindlehurst G DUKE POWER CO. |
| References | |
| PROJECT-669 TAC-MA4310, NUDOCS 9905030306 | |
| Download: ML20206D123 (7) | |
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'i April 27,1999 Mr. G. B. Swindlehurst, Chairman RETRAN Maintenance Group Steering Committee Duke Power Company
~ 526 S. Church Street Charlotte, NC 28201-1006
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION ON EPRI RETRAN-3D TOPICAL REPORT TR-7450 (PROJECT NO. 669) (TAC NO. MA4310).
Dear Mr. Swindlehurst:
By letter dated July 8,1998, EPRI submitted a request for NRC review of RETRAN-3D. By letter dated December 4,1998, the staff notified you of the staff's conclusion that the scope and detail of the code documentation pertaining to the thermal-hydraulic modeling, reactor -
1 kinetics modeling, code numerics, and code assessment are sufficient for the staff to initiate its technical review. ' The staff is continuing its review of the thermal-hydraulics portion of the RETRAN-3D topical report and concludes that additional information is necessary in order to.
complete its review of EPRI NP-7450, Volumes 1-4, Revision 2. The specific requests for information are contained in the enclosure and have been given unique identifiers to facilitate
' tracking.
As discussed previously with Mr. L. Agee of EPRI, you are requested to respond to the
. enclosed questions by close of business on May 21,1999. Additionally, the staff is willing to meet with EPRI prior to submittal of any responses in order to provide clarifications of the staff's request for additional information.
Sincerely, James H. Wilson, Senior Project Manager Generic Issues, Environmental, Financial, and Rulemaking Branch Division of Regulatory improvement Programs.
Office of Nuclear Reactor Regulation Project No. 669
Enclosure:
As stated cc: See next page r[@f/
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,o April 27,1999 Mr. G. B. Swindlehurst, Chairman RETRAN Maintenance Group Steering Committee Duke Power Company 526 S. Church Street-Charlotte, NC 28201-1006
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION ON EPRI RETRAN-3D TOPICAL REPORT TR-7450 (PROJECT NO. 669) (TAC NO. MA4310)
Dear Mr. Swindlehurst:
By letter dated July 8,1998, EPR! submitted a request for NRC review of RETRAN-3D. By letter dated December 4,1998, the staff notified you of the staff's conclusion that the scope and detail of the code documentation pertaining to the thermal-hydraulic modeling, reactor kinetics modeling, code numerics, and code assessment are sufficient for the staff to initiate its technical review. The staff is continuing its review of the thermal-hydraulics portion of the RETRAN-3D topical report and concludes that additional information is necessary in order so complete its review of EPRI NP-7450, Volumes 1-4, Revision 2. The specific requests for information are contained in the enclosure and have been given unique identifiers to facilitate tracking.
As discussed previously with Mr. L. Agee of EPRI, you are requested to respond to the enclosed questions by close of business on May 21,1999. Additionally, the staff is willing to meet with EPRI prior to submittal of any responses in order to provide clarifications of the i
1 staff's request for additional information.
Sincerely, (M. b Ja es H. Wilson, Senior Project Manager Generic issues, Environmental, Financial, and Rulemaking Branch Division of Regulatory improvement Programs Office of Nuclear Reactor Regulation Project No. 669
Enclosure:
As stated cc: See next page i
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OFFICE OF NUCLEAR REACTOR REGULATION REQUEST FOR ADDITIONAL INFORMATION EPRI TOPICAL REPORT NP-7450 l
RETRAN-3D l
PROJECT NO. 669 Theory (Volume 1) 1.1 For the Method of Characteristics, do the detailed subgrid profiles affect the node heat transfer or wall friction calculations?
1.2 The staff does not consider RELAP5 documentation to be a valid reference for the virtual mass coefficient. Provide a reference to a refereed journal.
1.3 A I correlations should include a range of applicability, a range of the data used to fit empirical parameters and the assessment range of the data. All correlations must be assessed with your code implementation.
1.4 What is the origin and assessment base for Equations Ill.4-Sa,b? The reference is to Collier, with no specific page cited. The equation appears to'be Equation 5.6 on page 141 cf Collier. No reference is given to the data it was derived from or any data it was assessed against. There is no assessment for this correlation, or many other basic i
correlations, in the assessment volume.
1.5 in the sections on condensing heat transfer (Sections 4.2.6,4.2.7), heat transfer correlations are given without defining the equations for the heat flux. Define the equations for how the heat flux is computed.
1.6 The dynamic flow regime model (DRFM) (Section 5.1.4, Page 111-144) appears to be new, but it is not marked as such. Is the DRFM new? There does not appear to be any 1
assessment of the DRFM or any justification of the chosen model parameters (Table 111.5-2). Is there an assessment of this model or any further documentation of the source of the model parameters?
1.7 What is the basis for Equation 111.6-417 The method for computing gas temperature in a steam noncondensible mixture is incorrect. Under equilibrium conditions, all components will be at the same temperature. A water-steam-noncondensible mixture will not maintain equilibrium conditions if it has input nor will it evolve to equilibrium conditions if non-equilibrium conditions are input.
User Manual (Volume 3)
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3.1 Sample problem BWR Rod Ejection uses a first word of -1 on Card 670010. The Users Manual does not show-1 as a word option. What is the effect of using this i
unsupported option? The cards are:
NED 1-8 9-16 12345678 670010-11000000 67001100000000
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. 3.2 The Users Guide on Page IV-137,2nd paragraph, mentions that the user needs to review Vol 1 to understand the correct use of the model. Provide an explanation on l
why a short summary within the text is not included so that the user properly utilizes the l
model without having to track down the theory manual. This is inconsistent with the suggestion that the modeling guide be used for understanding the proper use of the models.
3.3 In the Users Guide on Pages lil-12 and 111-13, the user is referenced to information about the file structure contained in 111.1-3 of the programmers manual. The actual information is contained in Section IV of the programmers manual. Resolve this inconsistency.
3.4 in the RETRAN-3D sample problem pipe. the control volume numbers used in the input deck do not correspond to the control,olume numbers used in the schematic diagram.
Resolve this inconsistency.
l 3.5 Volume Data Cards,05XXXY and W14-1 of the correlation guidelines, Hancox-Nicoll correlation, can be read at least three different ways. This is a concern because the user can modify the correlation coefficient without unambiguous guidelines on the effect. Provide unambiguous guidance to the user.
3.6 While performing the investigation of the 5-equation model, notice that the minor edit options included with the code do not specifically address the parameters of interest l
when you are using the 5-equation option. This makes it difficult to check the model behavior while using this option. Especially since RETRAN-3D does not print all of the parameters of interest, they are only available through the minor edits.
3.7 On Card 67400S, the User's Manual states that s is a card sequence number between 1 to 9. Yet in sample problem BWR Rod Drop, s=0. Provide clarification regarding this l
inconsistency.
3.8 The manual set refers the user to the RETRAN-02 Volume 5: Modeling Guidelines, EPRI NP-1850-CCM, November 1987. This information apears to be essential for the user and should be incorporated into the manual set, rather than directing the user to find a copy, in addition, because that staff has only a single copy, five ad6tional copies should be provided.
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3.9 When using the 5-equation model, there are tables which direct the user to input the volume specifics because code initialization is not available with this option. However, when following the input directions a warning message is written into the output file l
which says that the momentum balance is over specified and that the code is l
eliminating equations because of it. Then, it does not indicate which equations it is
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eliminating. Why not? How is the user to know which equations are discounted and l
why is it considered over-specified with this option when the information given was i
described in the user manual as required information?
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0 3-3.10 A description of the control rod numbering system used to denote the control rod layout in Tape 67 is not provided, nor is the numbering system used intuitive. Is there some mechanism to insure that the user uses the proper numbering system?
Assessment (Volume 41 4.1 in the natural circulation assessment (Section 6), why wasn't a bundle laminar wall friction correlation used? The bundle wall friction is greater than the tube wall friction j
that was used in the base case.
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In the Method of Characteristics (MOC) assessment (Section 7), the pulse appears to take on negative values after the initial positive pulse. is this caused by numerical dispersion or is there a physical mechanism for this behavior? Why is there no comparison to FRIGG test data for the MOC assessment? Why are spatial profiles not shown? Why is there no void profile assessment for the MOC method?
4.3 In the Peach Bottom Stability tests, the code generally overpredicted decay ratios. In the Vermont Yankee Tests, the code underpredicted decay ratios. Provide an explanation for the apparent discrepancy. if the code is to be used for stability calculations, why was it not assessed against the FRIGG stability tests?
4.4 There is a significant difference in reactivity insertion from void collapse between the 4-equation and 5-equation models in SWR pressurization events. Provide an assessment of RETRAN-3D against the void collapse data applicable to BWR pressurization events.
4.5 Provide an assessment of your subcooled boiling model under conditions that cover the expected range in BWR steady state and transient analysis.
General Comments and Questions G.1 In general the RETRAN-3D assessment does not display the level of rigor and completeness expected of a code planned to be an industry standard. Previous versions of the RETRAN code shared this problem. The staff placed numerous requirements on the code user to supply proper assessment of the code for the application being submitted for staff approval. At this time there is no indication that these requirements will not be imposed on the RETRAN-30 user as well.
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G.2 During staff audit calculations performed for the Westinghouse version of the RF.TRAN-2 code it was found that the turbine trip case would not run without a Westinghouse correction to the kinetic energy calculation for opening and closing
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valves. Has the correction been made to the RETRAN-3D code? Where is the correction described in the documentation if it has been made? If the correction has
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not been made, please explain how problems such as turbine trip are performed.
G.3 A large number of error reports and trouble reports have been submitted to the code developer. What is the status of resolution of the trouble reports?
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O 0 G.4 The Design Review Group made thirteen (13) recommendations regarding the RETRAN-3D code. What has been the disposition of those recommendations? Some of the recommendations appear to still be problems as they are also contained in some of the staff concerns provided above.
G.5 When the BWR rod drop sample problem was expanded into a full core deck with 24 channels, it was noted that the code no longer properly computes the fuel temperature
- or the conductor heating rates. This leads to an erroneous solution. Has the source of this problem been identified? Is it created through an undocumented code limitstion?
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8 Electric Power Research Institute Project No. 669 Mr. Kurt Yeager President and CEO Electric Power Research institute 3412 Hillview Avenue Palo Alto, CA 94303 Robin Jones Vice Presidet and Chief Nuclear Officer Electric Power Research Institute 3412 Hillview Avenue Palo Alto, CA 94303 Mr. Raymond C. Torok Project Manager, Nuclear Power Group Electric Power Research Institute Post Office Box 10412 Palo Alto, CA 94303 Mr. Lance Agee Electric Power Research Institute 3412 Hillview Avenue Palo Alto, CA 94303 Mr. Gary L. Vine Senior Washington Representative Electric Power Research Institute 2000 L Street, N.W., Suite 805 Washington, DC 2003C Mr. Bindi Chexal Electric Power Research institute Post Office Box 10412 Palo Alto, CA 94303 l
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