GNRO-2014/00064, Superseding Response to Request for Additional Information Regarding Maximum Extended Load Line Limit Plus Amendment Request, Dated 3/18/2014
| ML14247A124 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 09/04/2014 |
| From: | Coutu T Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML14248A149 | List: |
| References | |
| GNRO-2014/00064, TAC MF2798 | |
| Download: ML14247A124 (21) | |
Text
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~Entergy Contains PROPRIETARY Information GNRO-2014/00064 September 4,2014 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Entergy Operations, Inc.
P. O. Box 756 Port Gibson, MS 39150 Thomas Coutu Director, Regulatory Assurance Performance Improvement Grand Gulf Nuclear Station Tel. (601) 437-7511
SUBJECT:
Superseding Response to Request for Additional Information Regarding Maximum Extended Load Line Limit Plus Amendment Request, dated 3/18/2014.
Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29
REFERENCES:
1 Electronic Request for Additional Information Regarding Maximum Extended Load Line Limit Plus Amendment Request Dated 3/18/2014 (TAC MF2798) 2 Entergy Letter, "Maximum Extende.d Load Line Limit Analysis Plus (MELLLA+) License Amendment Request," GNRO-2013/00012, dated September 25,2013 (ADAMS Accession No. ML13269A140).
3 Entergy Letter, "Response to Request for Additional Information Regarding Maximum Extended Load Line Limit Plus Amendment Request, dated 2/6/14," GNRO-2014/00024, dated March 10,2014 (ADAMS Accession No. ML14069A103)
Dear Sir or Madam:
Entergy Operations, Inc. is providing in the Attachments a superseding response to the Reference 1 Request for Additional Information (RAI).
In Reference 3, Entergy Operations, Inc. (Entergy) submitted to the NRC responses to an RAI pertaining to a License Amendment Request (LAR) regarding Maximum Extended Load Line Limit Plus (MELLLA+). Included in this submittal was a response to RAI 1.
This letter supersedes the response to RAI 1 transmitted to the Nuclear Regulatory Commission (NRC) in Reference 3. The superseding RAI 1 response is in support of the NRC's review of Reference 2, and the superseding response to RAI 1 is based on the NRC audit conducted at GE-Hitachi Nuclear Energy Americas LLC (GEH) on April 23-25, 2014. contains proprietary information as defined by 10 CFR 2.390. GEH, as the owner of the proprietary information, has executed the attached affidavit, which identifies that the When Attachment 1 is removed from this letter, the entire document is NON-PROPR~ETARY
GNRO-2014/00064 Page 2 of 2 attached proprietary information has been handled and classified as proprietary, is customarily held in confidence, and has been withheld from public disclosure. The proprietary information was provided to Entergy in a GEH transmittal that is referenced by the affidavit. The proprietary information has been faithfully reproduced in the attachment such that the affidavit remains applicable. GEH hereby requests that the attached proprietary information be withheld from public disclosure in accordance with the provisions of 10 CFR 2.390 and 9.17. Information that is not considered proprietary is provided in Attachment 2. Attachment 3 contains an affidavit which identifies that the information contained in Attachment "1 has been handled and classified as proprietary to GEH. On behalf of GEH, Entergy requests that Attachment 1 be withheld from public disclosure in accordance with 10 CFR 2.390(b)(1).
This letter contains no new commitments. If you have any questions or require additional information, please contact Mr. James Nadeau at 601-437-2103.
Sincerely, e,~~
TC/tmc Attachments: 1. Proprietary Superseding Response to Request for Additional Information
- 2. Non-Proprietary Superseding Response to Request for Additional Information
- 3. GEH Affidavit for Enclosure 1 cc: with Attachments U.S. Nuclear Regulatory Commission ATTN: Mr. Marc L. Dapas R'egional Administrator, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 U.S. Nuclear Regulatory Commission ATTN: Mr. A. Wang, NRR/DORL Mail Stop OWFN/8 G14 Washington, DC 20555-0001 NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150 State Health Officer Mississippi Department of Health P. O. Box 1700 Jackson, MS 39215-1700 to GNRO-2014/00064 Non-Proprietary Superseding Response to Request for Additional Information This is a non-proprietary version of Attachment 1 which has the proprietary information removed. Portions of the document that have been removed are indicated by an opan and closed bracket as shown here ((
)).
ENCLOSURE 2 GEH-GGNS-AEP-640 Response to RAI 1 in Support ofGGNS MELLLA+ LAR Non-Proprietary Information - Class I (Public)
NON-PROPRIETARY NOTICE This is a non-proprietary version of Enclosure 1 of GEH-GGNS-AEP-640 which has the proprietary information removed.
Portions of the document that have been removed are indicated by an open and closed bracket as shown here ((
)).
Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640 RAIl Page 1 of 12 Section 9.3.3 of Attachment 4 states that zirconium credit will be used in the Shumway correlation. The NRC staffhas reviewed the zirconium data described in letter dated September 9,2013 (ADAMS Accession No. ML13253A105), from GE Hitachi Nuclear Energy and has the following questions a.
Fresh fuel that has little or no oxide at the start ofthe transient and the fresh fuel is often in the more reactive part ofthe core; therefore, it is the data ofinterest. Figure 6 ofthe September 9, 2013, letter has many data sets provided together on it.
Provide a plot showing clean zirconium separate from all the other data including SS, Inconel, zirconium oxide and any data that would be expected to have oxidized zirconium.
b.
In the September 9, 2013 letter, much ofthe Hoffman (FKZ) data that has a rapid cooling rate early in the experiment that may have been incorrectly interpreted as quench.
A closer examination ofthe data shows this initial cooling was due to startup ofthe test and that quench occurred much later at significantly lower temperatures.
In addition, because ofhigh temperatures during the tests and pre-conditioning ofthe rods, the rods are likely have thick oxide layer thicknesses that are not representative offuel in a commercial reactor undergoing an Anticipated Transient without Scram with Instability (ATWS-I) event.
Provide a plot showing the data considered valid by the licensee for justifying Shumway as implemented in TRACG for the intended application (e.g. ATWS-I under MELLLA+).
Textual justification to support the choice of the selected data and exclusion ofthe other data should be providedfocusing on comparing the applicable test conditions to the plant application conditions to support a conclusion that the data is applicable.
GEH Response to Parts (a) and (b)
Other materials were included in the original Figure 6 of Reference 1-1 to illu'strate that the Shumway correlation matches very nicely the trend in both the data and the correlation from Henry over a wide range of material thermal properties and water pressures. Data for zirconium (Zr) with or without oxide is limited for the reasons cited in Reference 1-1 so consideration of collaborative evidence using other materials is essential and commonly practiced in designing experiments. Another key point being made in Reference 1-1 is that the presence of zirconium dioxide (Zr02) increases the value for Tmin and this credit is conservatively not utilized by the Shumway*correlation.
As requested in Part (a) of the RAI, data for stainless steel (SS) and Inconel have been removed from the original Figure 6 of Reference 1-1 together with the correlation curves pertaining to these materials and zirconium dioxide. The revised plot is provided in Figure 1-1. The solid red curve in Figure 1-1 is for the Shumway correlation using unoxidized zircaloy properties and no credit for the void term. The correlation as implemented in TRACG compares very well to the data shown by solid red circles that was characterized by Peterson and Bajorek (Reference 1-3) for clean zircaloy samples. There were no data points on the original figure that were specific to Zr02 although many of Hofmann's data points (Reference 1-2) were from zircaloy cladding that had some oxide layer on the surface as indicated by the figure legends. Fresh fuel does have less oxide at the start of the transient than fuel that has been exposed; however, the assertion that Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640 Page 2 of 12 fresh boiling water reactor (BWR) fuel is "often in the more reactive part of the core; therefore, it is the data of interest" is not accurate. The hot rods in the hot fuel bundles in the core are of interest. The location in the core is not important. It is the highest power fuel bundles that are important. The highest reactivity fuel bundles generally result in the highest power. Because of the presence of gadolinium, the peak reactivity for a typical BWR fuel bundle occurs at an exposure between 10 and 20 GWdlMTU which occurs roughly for fuel towards the end of its first cycle. Oxide accumulates slowly as a function of exposure during normal BWR operations.
The exposure argument is not relevant due to that fact that the amount of pre-transient oxide remains low because the normal BWR clad operating temperature is low and there is very limited oxygen availab~e to form an oxide. Based on measured oxide data, the maximum pre-transient oxide is less than ((
)) even for exposures as high as ((
)).
Initial oxide amounts for the Hofmann (FKZ) tests were carefully created using controlled pre-transient conditioning at high temperatures with cooling supplied mainly by argon to limit the oxygen available for oxidation.
Nominal pre-transient oxide layers from 0 to 350 ~m were studied and the amount of oxide predicted by calculations was confirmed by measurements. For the pre-oxidized specimens, steam was mixed with the argon to provide an' oxygen source and the time and temperature were controlled to achieve the desired amount of oxidation.
Any additional oxide formation during the transient tests has been estimated for each test by integrating the Cathcart reaction rate equation from the beginning of the transient to the quench time using an average of the reaction rates at the initial and final conditions.
The oxide production rate increases exponentially with temperature but also decreases inversely proportional to the accumulated oxide thickness. The time at the high temperature where oxygen from water is also available to form oxide was relatively short so the incremental amounts of oxide formed during the Hofmann transients are relatively small once some oxide has formed.
The original Figure 6 from Reference 1-1 was constructed by reviewing more than 85 data traces from Hofmann and rejecting all but those where the quench was obvious. The original usable set included seven for zero oxide, 16 for 100 ~m oxide, and 24 at 300 ~m oxide.
Part (b) of the RAI asserts that "initial cooling was due to startup of the test and that quench occurred much later at significantly lower temperatures."
It is true that early temperature decreases recorded for the thermo-couples at the upper and middle elevations can easily be misinterpreted as a quench when in fact the rapid temperature reduction may be due to a sudden increase in steam cooling as quenching occurred at a lower elevation.
All data traces were critically reviewed again with attention on whether the temperature reduction rate was maintained at a high or increasing value after the time the quench temperature was recorded.
Also the time of the quench has been recorded.
Quench times less than 5.0 seconds are not expected for the thermo-couples at the center and upper elevations. Temperature traces that did not meet this additional scrutiny were rejected.
Most notably, six of the seven original temperature traces with zero oxide were eliminated so that only one trace remained (and it is questionable as suggested by the red highlighting in Table 1-1). The more objective criteria were also applied to the traces that had 100 ~m and 300 ~m pre-transient oxides which resulted in the removal of a few traces and the addition of a few others. The revised statistics are presented in Table 1-1.
In view of the standard deviations, there is no statistically significant difference in the quench temperatures as the initial oxide increases from 100 to 300 ~m. The key points are that the Hofmann data supports the material property dependence in the Shumway correlation Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640 Page 3 of 12 and assuming clean zircaloy in the application of the correlation results in a Tmin value that is conservatively below the data.
Table 1-1 Oxide (J.lrn) 0 100 16 469 839 554 574 97 300 24 389 809 539 562 124 All 40 389 839 539 567 113 Details for forty-two (42) temperature traces from Hofmann are presented in Table 1-2 to facilitate independent critical review of how the data traces in Reference 1-2 were processed.
The two data points shaded in red in Table 1-2 are unbelievably high and significantly different from all the other values in the table. These values are from two thermo-couples (TICs) at the lowest elevation so an early quench time is expected. The temperature traces from which these points were obtained appear to indicate a liquid quench; however, it is also possible that the traces are indicating that these TICs detached from the rod or failed in some other way. These two red data points are not shown in Figure 1-1 and they are not considered in the statistics in Table 1-1.
Non-Proprietary Infonnation - Class I (Public)
GEH-GGNS-AEP-640 Page 4 of 12 Table 1-2 Details for Hofmann TQ Values Quench TQ-Page Figure(s)
Elevation Curve Time Tsat (s
106 3.15 3.16 lower L1007 1 800 5.1 689 100 1.9 107 3.17 3.18 center C1007 1 720 9.0 609 100 3.4 108 3.19 3.20 u
er U1007 1 680 17.1 569 100 6.3 108 3.19 3.20 u
er U31056 1 600 14.0 489 100 5.2 115 3.33 3.34 lower L0507 1 950 1.8 839 100 0.2 115 3.33 3.34 lower L29056 1 750 2.6 639 100 0.3 116 3.35 3.36 center C0507 1 750 6.6 639 100 0.7 116 3.35 3.36 center C29056 1 650 9.0 539 100 0.9 117 3.37 3.38 u
er U0507 1 650 9.6 539 100 1.0 117 3.37 3.38 u
er U29056 1 730 10.0 619 100 1.0 124 3.51. 3.52 lower L04066 1 680 2.2 569 100 0.0 124 3.51. 3.52 lower L0607 1 580 4.0 469 100 0.1 125 3.53 3.54 center C04066 1 590 7.6 479 100 0.2 125 3.53 3.54 center C0607 1 630 7.0 519 100 0.1 126 3.55 3.56 u
er U04066 1 630 7.8 519 100 0.2 126 3.55 3.56 u
er U0607 1 580 8.7 469 100 0.2 Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640 Page 5 of 12 Table 1-2 includes the details for 24 experiments that had 300 ~m of pre-transient oxide (shaded rows).
As requested, these points have not been included in Figure 1-1 since the amount by which the quench temperature would be reduced, to determine an equivalent clean zirconium temperature from the data, for significant amounts of Zr02, has not been well established. There*
is no consensus in the literature regarding how thick the oxide must be before the impact on the, minimum stable film temperature becomes significant. The statistics in Table 1-1 suggest there is no statistically significant difference in the quench temperatures as the initial oxide increases from 100 to 300
~m.
Dhir (Reference 1-7) acknowledges that the "effect of oxidation on quenching behavior is most difficult to quantify."
In several places Dhir states that the quenching temperature on oxidized zircaloy surfaces was 50 to 80 K higher than on fresh surfaces but does not indicate the amount of oxide required to cause this difference. Even if all the Hofmann 100 ~m data points in Figure 1-1 were shifted downward by 80 K all data points would still be above the curve for clean zircaloy from the Shumway correlation.
This observation supports the conclusion that the Shumway correlation (as applied) is conservatively low for the intended applications.
Wendelstorf and others in Reference 1-8 applied a thin sheet approximation that shows how the presence of an oxide layer impacts the effective heat transfer coefficient (HTCeff) near the surface of the oxidized metal.
The work was motivated by the need to understand how oxide impacts the spray cooling of steel but the theory is applicable also to Zr and Zr02. For stainless steel Wendelstorf concludes that "the theoretical effect of thin homogeneous and adhesive oxide layers on heat transfer is significant only for layers of 100 ~m thickness and above'."
His conclusion is based on how much HTCeff is reduced as oxide increases. A similar statement can be made for Zr and Zr02 by adapting the approach used in Reference 1-8 to the fuel cladding geometry and the properties of Zr and Zr02. It should be noted that for a low convective heat transfer coefficient such as that for film boiling that the resistance of the Zr02 layer is not a major contributor to the overall thermal resistance from the fuel pellet surface to the coolant. For a high convective heat transfer coefficient such as that for nucleate boiling the presence of a Zr02 layer has a higher percentage impact on the overall thermal resistance but still produces relatively small absolute changes in the temperature difference from the fuel pellet surface to the coolant.
Figure 6 of Reference 1-1 included 61 data points from Peterson and Bajorek (Reference 1-3).
Of the total 61 data points, 24 were characterized as clean or unoxidized and 37 were labeled as oxidized.
Reference 1-3 focused on how oxidization changes the surface roughness and characterized the test samples in this way. No oxide thickness values were documented. For the 37 points that were labeled as oxidized samples, there were 13 points where the roughness values were more than a factor of three higher than the unoxidized values indicating the presence of substantial amounts of oxide.
These 13 points have been removed and are not present in Figure 1-1. All 24 of the original points for unoxidized samples have been retained.
Another 24 points for the so-called oxidized samples had average roughness values (1.6 ~m) that were less than the unoxidized samples (1.7 ~m). These samples were retained because they could not have had any significant amounts of oxide and still had such a low roughness. The two different data sets from Peterson and Bajorek independently support the suggestion from Wendelstorf that thin oxide layers do not significantly affect the overall heat transfer.
It is expected that the Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640 Page 6 of 12 lightly oxidized data from Reference 1-3 should have a slightly higher quench temperature (see Figure 1-1).
Figure 6 of Reference 1-1 included ten data points from GEAP-13112 (Reference 1-4).
The maximum stated oxide in the GEAP-13112 report was estimated as 1.8 mil (45.7 Jlm).
All GEAP-13112 points have been removed from Figure 1-1 but not because of the amount of oxide.
Although the quench temperatures do indicate the ability to rewet the dry cladding surface from an elevated temperature following a LOCA, quenching by spray from high-void conditions as used in the GEAP-13112 tests is not representative of the quenching that occurs in an ATWSI scenario.
It is for this reason that the ten data points from GEAP-13112 previously shown in Figure 6 ofReference 1-1 have been omitted from Figure 1-1.
For purposes of evaluating the modeling of Tmin for applicability to ATWSI originating from MELLLA+ conditions, the most representative zircaloy data is that from the Halden experiments (References 1-5 and 1-6). Because the GEH implementation of the Shumway correlation does not credit void fraction or oxidation, the two most important parameters for Tmin applicability are the pressure and wall material property.
Most data shown in Figure 1-1 are at low pressures relative to a MELLLA+ ATWSI analysis. Because no depressurization is expected in an ATWSI event, the pressure range is approximately 7 to 8 MPa. The Halden data were recorded for fluid pressures ranging from 6.5 to 6.9 MPa using a zircaloy BWR fuel rod segment.
Also, the average heat fluxes in the Halden tests correspond well to those expected in an ATWSI scenario after the power is reduced by reducing core flow. Boiling transitions experienced in the Halden tests were a result of the low flow, which is the same causal mechanism for boiling transition during an ATWSI.
The cooling as liquid flow that was suddenly restored in the tests also emulates the cooling that occurs when flow upsurges during an ATWSI flow oscillation. These conditions in a BWR fuel channel are generic for ATWSI power/flow conditions where large oscillations can occur.
The only distinction being that the more reactive control rod line for MELLLA+ used in the plant calculations is more likely to result in higher channel power and earlier onset of instability as the core flow is reduced.
All of the Halden data described and presented in Reference 1-1 has been retained here in Figure 1-1 because it is judged, based on the discussion above, that the Halden test conditions are the most representative of the conditions expected in an ATWSI scenario for MELLLA+ conditions once the power and flow oscillations grow to the point that boiling transitions occur and could result in cladding temperatures that approach or exceed Tmin.
There is no indication in the Halden reports how much oxide accumulated during the tests. The accumulated amount has been conservatively calculated by considering the number of boiling transition (BT) events, the maximum temperature for each event, and the duration of each event for each rod segment. The amount of oxide produced during a BT event averaged 2.4 Jlm with a minimum to maximum range of 0.2 to 6.9 Jlm. The highest value was calculated for a segment conservatively assumed to have zero initial oxide.
The maximum accumulated oxide for the series of tests was less than 50 Jlm for the rod segment that experienced the most BT events.
These calculated numbers should be considered as rough estimates to support the conclusion that the accumulated oxide amounts were not excessive and thus the Halden data points support the conclusion that the Shumway correlation as applied is conservative.
Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640 Page 7 of 12 As documented in Reference [1-1], the plotted temperature values for the Halden tests in Figure 6 had been adjusted upward based on the discussion in Section 2.4 ofHWR-666 (Reference [1-9]). It is conservative to not apply these adjustments because it lowers the data points. Even without the adjustments, the Shumwary correlation still conservatively under predicts the Halden data as shown in Figure 1-1. Note that even the minimum Halden data point is 28 K above what is predicted by the Shumway correlation for unoxidized zircaloy.
In Figure 1-1, the solid red curve obtained from the Shumway correlation using zircaloy material properties is below essentially all of the zircaloy TQ values extracted from References 1-2 through 1-6. The data supports the conclusion that the Shumway correlation is conservative for the intended applications in the TRACG code.
There are several plausible explanations (not related to oxide) for why the Shumway correlation is conservatively lower than the bulk of the data. For the correlated curve plotted in Figure 1-1, the ReYnolds number was assumed to be zero. The ReYnolds number dependence is relatively small in the Shumway correlation (about 10% of Tmin-Tsat) and accounting for it using test conditions at the key time when the cladding temperature equals Tmin increases the correlation curve between 27 to 39 K depending on the specific test.
This offset does not change the conclusion that the Shumway correlation is conservative overall compared to the test data. The Shumway correlation (solid red curve) was
\\ also evaluated assuming that a = 1 so no credit would be realized from the term [1 +(1 - a) 2
] in the correlation. This term has been judged to have inadequate experimental support because in Shumway's words it is based on "a small amount of unpublished Semiscale void data" and the "accuracy of the void effect is untested". Especially for the cases of the Hofmann and Halden data, the quench occurs for a much lower void fraction than 1.0 just based on how the liquid water was forced into the test section.
It is also likely that a credit for liquid subcooling is observed in the data that is not represented in the Shumway correlation. As an upper bound on the temperature prediction from the Shumway correlation, a value of a = 0 was assumed to obtain the dashed red curve in Figure 1-1. As expected, the dashed curve follows the trend in the data with pressure but is higher than the data.
In applications of the Shumway correlation in TRACG analyses the term
[1 + (1-a)2 ] is replaced by 1.0 because of the inadequate experimental support for this term and more importantly so that the Shumway correlation as applied will predict a conservatively lower value for Tmin (solid red curve).
For TRACG applications to BWR ATWSI scenarios, the Shumway Tmin correlation is aIPlied for zircaloy properties including the ReYnold's dependence but without the [1 +(1-a)2 term.
The Shumway Tmin model has been applied in this way to perform TRACG transient calcu ations for four ofthe Halden tests[I-6] where the peak measured temperatures were the highest. ((
))
Comparisons between the calculated and measured temperatures are shown in Figures 1-2 through 1-5. In all the plots the test results are shown by the solid black curve and the TRACG calculated results at the elevation of the thermocouple are shown by the solid red curve.
The green curve in each plot shows the calculated absolute value of Tmin at the same elevation.
For Experiments 11 and 12, ((
Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640 Page 8 of 12
)) Experiment 11 involved a series of 6 dryout tests.
Only the dryout that resulted in the highest peak measured temperature was simulated which corresponds to Test 11c for which the time interval of interest is from 930 to 970 seconds as shown in Figure 1-4.
See Reference [1-6] for more details about the Halden experimental setup and the tests.
The green curve for Tmin in Figures 1-2 through 1-5 reflects the local calculated conditions in the cell where the thermocouple is located. Initially all the Tmin values are slightly above 900 K and they remain essentially constant until the flow is reduced. A slight decrease of less than 9 K in the initial Tmin values corresponds to the decrease in the initial flows from around 100 liters/hr to approximately zero which gets reflected in the ReYnold's term in the Shumway correlation.
Once boiling transition occurs the clad surface temperature starts to increase which causes the calculated Tmin values to decrease in response to how the zircaloy material properties' change with temperature.
This trend is reversed after the flow is restored and the calculated clad temperature initially starts to decrease because of increased steam cooling as is evident when comparing the peak in the red curve with the minimum in the green curve in each figure. Once the decreasing calculated temperature (red curve) drops below the increasing Tmin (green curve) there are changes in the slopes of both curves because the heat transfer mode returns,from transition boiling to the higher heat transfer coefficients associated with nucleate boiling. Finally the measured and calculated clad temperatures drop to values similar to but slightly below their initial values as a result of very high inflow of subcooled water. The subcooling is around 5K.
The increase in the calculated Tmin at the end of the test compared to the initial value is due primarily to the higher final flow relative to the initial flow. The increase in Tmin due only to the flow component results in an increase in Tmin of between 13 K for Test 12 and 42 K for Test 4.
Note that in the TRACG implementation, Tmin is not needed or calculated when the clad surface temperature drops below the saturation temperature (Tsat) so until the clad value again exceeds Tsat the value for Tmin is shown at the last calculated value.
The clad temperature results in Figures 1-2 through 1-5 show good agreement between the calculated and measured temperature values and the timing for quenching behavior after the peak as heat transfer conditions evolve from transition boiling back to nucleate boiling. The timing is very important for ATWSI conditions and cannot be achieved without using a reasonable model for Tmin that utilizes zircaloy properties.
Summary The Shumway correlation for Tmin properly accounts for a wide range of material properties and water pressures as evidenced by the comparisons to data in Figure 6 of Reference 1-1.
As requested, the collaborating data for other materials has been removed from this document leaving only zircaloy. All the zircaloy data points from Figure 6 of Reference 1-1 were reviewed to evaluate if they were applicable for the intended purpose of supporting the use of the Shumway correlation for unoxidized zircaloy to calculate Tmin used in ATWSI calculations. The zircaloy data from GEAP-13112 (Reference 1-4) was excluded because quenching occurred by spray cooling into a steam environment from above whereas quenching in an ATWSI occurs by liquid water.
The thickness of the zirconium dioxide (Zr02) that was initially present in the Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640 Page 9 of 12 specimens or that accumulated during the tests was also considered. The data points that were retained contained a total accumulated Zr02 layer of less than 120 /lm.
All the Hofmann data (Reference 1-2) traces were carefully scrutinized to ensure proper recording of the quench temperatures.
Hofmann data obtained from specimens with an initial 300 /lm zr02 layer was removed even though this data does not indicate an increase in quench temperatures relative to the data obtained from the samples where the initial Zr02 layer was 100 /lm. The Peterson and Bajorek (Reference 1-3) data with roughness values above the clean zircaloy roughness values were also removed because high roughness values imply a thick Zr02 layer that was not quantified by the researchers. The remaining zircaloy data was plotted in Figure 1-1 along with two examples of the Shumway correlation for zircaloy properties. As shown in Figure 1-1, the Shumway correlation without the void term credit as proposed for TRACG ATWSI applications provides an appropriately conservative lower-bound estimate of Tmin for zircaloy data from Hofmann and Halden. Lower values of Tmin are more conservative because they delay the return to nucleate boiling and thus result in higher and more conservative calculated values for the wall temperature (Tw).
Application of the Shumway Tmin correlation using zircaloy properties has been qualified by simulating four relevant Halden tests that represent conditions similar to those encountered in BWR ATWSI analyses.
Demonstrated good agreement between the calculated and measured temperature values and the timing for quenching behavior after the peak temperature support application of the model for BWR ATWSI conditions.
((
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Figure 1-1 Shumway Correlation Compared to Zircaloy Data versus Pressure Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640
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Page 10 of 12
))
Figure 1-2
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Figure 1-3 TRACG Calculated Clad Temperature Compared with Halden Experiment 3 Data
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TRACG Calculated Clad Temperature Compared with Halden Experiment 4 Data Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640
((
Page 11 of12
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Figure 1-4
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Figure 1-5 TRACG Calculated Clad Temperature Compared with Halden Experiment lIe Data
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TRACG Calculated Clad Temperature Compared with Halden Experiment 12 Data Non-Proprietary Information - Class I (Public)
GEH-GGNS-AEP-640 References Page 12 of 12 1-1 Use of the Shumway Tmin correlation with Zircaloy for TRACG Analyses, Letter IF.
Harrison (GEH) to NRC Document Control Desk, MFN 13-073 (ADAMS Accession No. ML13253A105), September 9, 2013.
1-2 Hofmann, P. et aI., Quench Behavior of Zircaloy Fuel Rod Cladding Tubes: Small-Scale Experiments and Modeling of the Quench Phenomena, FZKA 6208, Forschungszentrum Karlsruhe, March 1999.
1-3 Peterson, L.J. and S.M. Bajorek; Experimental Investigation of Minimum Film Boiling Temperature for Vertical Cylinders at Elevated Pressure; Proceedings of ICGNE10 10th; Arlington, VA; April 14-18, 2002.
1-4 Duncan, J.D. and J.E. Leonard, Thermal Response and Cladding Performance of an Internally Pressurized Zircaloy-Clad Simulated BWR Fuel Bundle Cooled by Spray Under Loss-of-Coolant Conditions, GEAP-13112, April 1971.
1-5 McGrath, M., Minutes of the Fourth Workshop on Dry-out Fuel Behaviour Tests (IFA-613), HWR-499, GECD Halden Reactor Project, April 1997.
1-6 Ianiri, R., The Third Dryout Fuel Behaviour Test Series in IFA-613, HWR-552, GECD Halden Reactor Project, February 1998.
1-7 Dhir, V.K. et aI., Quenching Studies on a Zircaloy Rod Bundle, Journal of Heat Transfer, Vol. 103, pp. 293-299, May 1981.
1-8 Wendelstorf, R. et aI., Effect of Oxide Layers on Spray water Cooling Heat Transfer at High Surface Temperatures, Journal of Heat and Mass Transfer, Vol. 51, pp. 4892-4901, 2008.
1-9 McGrath, M. et aI., Investigation into the Effects ofIn-Pile Dry-Out Transients on Zircaloy Fuel Cladding as Performed in IFA-613, HWR-666, GECD Halden Reactor Project, March 2001.
to GNRO-2014/00064 GEH Affidavit for Enclosure 1
ENCLOSURE 3 GEH-GGNS-AEP-640 GEH Affidavit for Enclosure 1
GE-Hitachi Nuclear Energy Americas LLC AFFIDAVIT I, Peter M. Yandow, state as follows:
(1)
I am the Vice President, NPP/Services Licensing, Regulatory Affairs, GE-Hitachi Nuclear Energy Americas LLC ("GEH"), 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 GEH letter, GEH-GGNS-AEP-640, "GEH Response Superseding GGNS MELLLA+ RAIl," dated July 1, 2014. The GEH proprietary information in Enclosure 1, which is entitled "Response to RAI 1 in Support of GGNS MELLLA+ LAR," is identified by a dotted underline inside double square brackets.
((J.~i~..~.~D-t~ll.C;~..~~._fl.n.~~~mp.J.~..?!)) Figures and large objects are identified with double square brackets before and after the object.
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, GEH relies upon the exemption from disclosure set forth in the Freedom ofInformation Act ("FOIA"), 5 U.S.C. Sec. 552(b)(4), and the Trade Secrets Act, 18 U.S.C.
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 qualifies 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, 975 F.2d 871 (D.C. Cir. 1992), and Public Citizen Health Research Group v. FDA, 704 F.2d 1280 (D.C. Cir. 1983).
(4)
The information sought to be withheld is considered to be proprietary for the reasons set forth in paragraphs (4)a. and (4)b. Some examples of categories of information that 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 GEH's competitors without license from GEH constitutes a competitive economic advantage over other companies; b.
Information that, if used by a competitor, would reduce their expenditure of resources or improve their competitive position in the
- design, manufacture,
- shipment, installation, assurance of quality, or licensing of a similar product; c.
Information that reveals aspects of past, present, or future GEH customer-funded development plans and programs, resulting in potential products to GEH; d.
Information that discloses trade secret or potentially patentable subject matter for which it may be desirable to obtain patent protection.
Affidavit for GEH-GGNS-AEP-640 Page 1 of3
GE-Hitachi Nuclear Energy Americas LLC (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 GEH, 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 GEH, not been disclosed publicly, and not been made available in public sources. All disclosures to third parties, including any required transmittals to the NRC, have been made, or must be made, pursuant to regulatory provisions or proprietary or confidentiality agreements that provide for maintaining the information in confidence. The initial designation of this information as proprietary information, and the subsequent steps taken to prevent its unauthorized disclosure, are as set forth in the following paragraphs (6) and (7).
(6)
Initial approval of proprietary treatment of a document is made by the manager of the originating component, who is the person most likely to be acquainted with the value and sensitivity of the information in relation to industry knowledge, or who is the person most likely to be subject to the terms under which it was licensed to GEH.
(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 for technical content, competitive effect, and determination of the accuracy of the proprietary designation. Disclosures outside GEH 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 or confidentiality agreements.
(8)
The information identified in paragraph (2), above, is classified as proprietary because it contains detailed results and conclusions regarding supporting evaluations of the safety-significant changes necessary to demonstrate the regulatory acceptability of the Maximum Extended Load Line Limit Analysis Plus analysis for a GEH Boiling Water Reactor
("BWR"). The analysis utilized analytical models and methods, including computer codes, which GEH has developed, obtained NRC approval of, and applied to* perform evaluations ofMaximum Extended Load Line Limit Analysis Plus for a GEH BWR.
The development of the evaluation processes along with the interpretation and application of the analytical results is derived from the extensive experience and information databases that constitute a major GEH asset.
(9)
Public disclosure of the information sought to be withheld is likely to cause substantial harm to GEH's competitive position arid foreclose or reduce the availability of profit-making opportunities. The information is part of GEH'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 evaluatlon process. In addition, the technology base includes the value derived from providing analyses done with NRC-approved methods.
Affidavit for GEH-GGNS-AEP-640 Page 2 of3
GE-Hitachi Nuclear Energy Americas LLC The research, development, engineering, analytical and NRC review costs comprise a substantial investment of time and money by GEH. 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. GEH's competitive advantage will be lost if its competitors are able to use the results of the GEH 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 GEH 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 GEH 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 ofperjury that the foregoing affidavit it true and correct.
Executed on this 1st day ofJuly 2014.
/~&avc0 Peter M. Yandow Vice President, NPP/Services Licensing Regulatory Affairs GE-Hitachi Nuclear Energy Americas LLC 3901 Castle Hayne Road Wilmington, NC 28401 Affidavit for GEH-GGNS-AEP-640 Page 3 of3