ML20217P863
| ML20217P863 | |
| Person / Time | |
|---|---|
| Issue date: | 04/08/1998 |
| From: | Birmingham J NRC (Affiliation Not Assigned) |
| To: | Joseph Kelly BABCOCK & WILCOX OPERATING PLANTS OWNERS GROUP |
| References | |
| PROJECT-693 TAC-M98962, NUDOCS 9804100212 | |
| Download: ML20217P863 (5) | |
Text
l
. April 8, 1998 l
g Mr. J. J. K;lly, M: nager j
! B&W Owners Group Services '
Framatome Technologies, Inc.
P.O. Box 10935 Lynchburg, VA 24506-0935
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR TOPICAL BAW-2241P,
" FLUENCE AND UNCERTAINTY METHODOLOGIES"(TAC NO. M98962)
Dear Mr. Kelly:
f l
' By letter dated May 14,1997, the Babcock and Wilcox Owners Group (B&WOG) submitted topical BAW-2241P for NRC review. On January 30,1998, the staff sent you a request for additional information. Since then the staff has completed its review of the report and has
{ determined a need for additional information. The additional information requested is identified l
[ in the enclosure to this letter. The NRC requests that the B&WOG respone' to this request and !
the previous request expeditiously so that the staff may complete it's. review in a timely manner.
You should address your response to the NRC Document Control Desk and reference B&WOG l
Project No. 693.
If ycu wish to meet with the staff to accelerate the information transfer, the staff woulo welcome I
a meeting at a mutually convenient time. If you have any questions on this matter, please j contact me by phone,301/415 2829, or by email, jlb4@nrc. gov.
i Sincerely, y i
Original Signed By:
Joseph L. Birmingham, Project Manager Generic issues and Environmental Projects Brancn Office of Nuclear Reactor Regulation
Enclosure:
Questions on topical BAW-2241P
- cc
- Mr. R. B. Borsum, Mmieger Rockville Licensing Operations Framatome Technologies, Inc.
l 1700 Rockville Pike, Suite 525 Rockville, MD 20852-1631 DISTRIBUIlON:
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9 . . . . . ,d April 8, 1998 Mr. J. J. Kelly, Manager B&W Owners Group Services Framatome Technologies, Inc.
P.O. Box 10935 Lynchburg, VA 24506-0935
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR TOPICAL BAW-2241P,
" FLUENCE AND UNCERTAINTY METHODOLOGIES"(TAC NO. M98962)
Dear Mr. Kelly:
By letter dated May 14,1997, the Babcock and Wilcox Owners Group (B&WOG) submitted topical BAW-2241P for NRC review. On January 30,1998, the staff sent you a request for additionalinformation. Since then the staff has completed its review of the report and has determined a need for additionalinformation. The additional information requested is identified in the enclosure to this letter. The NRC requests that the B&WOG respond to this request and the previous request expeditiously so that the staff may complete it's review in a timely manner.
You should address your response to the NRC Document Control Desk and reference B&WOG Project No. 693.
If you wish to meet with the staff to accelerate the information transfer, the staff would welcome a meeting at a mutually conver.ient time. If you have any questions on this matter, please contact me by phone,301/415-2829, or by email, jib 4@nrc. gov.
Sincerely,f , 4 l . :/ b 9 vn * - -
Joseph LIBirmingham, Project Manager Generic issues and Environmental Projects Branch Office of Nuclear Reactor Regulation
Enclosure:
Questions on topical BAW-2241P cc: Mr. R. B. Borsum, Manager Rockville Licensing Operations Framatome Technologies, Inc.
1700 Rockville Pike, Suite 525 Rockville, MD 20852-1631
f.
REQUEST FOR ADDITIONAL INFORMATION; BAW-2241
- 1. Equations (7.4) and (7.5) appear to incorrectly combine (%) relative errors and l
absolute errors (e.g., measured in cm or mg). Please explain this apparent l inconsistency.
- 2. Why is the helium concentration of samples DB-BEC,9/26,9/27,4/10 and 4/12,
- and DB-Li-5A and 5B (Tables B-4.2-1 and B-4.2-2) a factor of- 10 less than the l other samples? Are these' samples shielded?
- 3. Provide the values and basis for the measurement errors assumed in determining the dosimeter uncertainties of Tables 7-2 and 7-3.
- 4. Why are the dosimeter measurement uncertainties of Tables 7-2 and 7-4 different?
Which values are used in the FTI analysis?
- 5. Using a conservatively large or bounding value for the measurement uncertainty with Equation (7.9) results in a nonconservative estimate for the calculation uncertainty. A conservative calculation uncertainty should be determined using a minimum value for the measurement uncertainty.
- 6. The form of Equation (7.6) appears to be incorrect. Also, provide the values and basis for w ,, pm.,, wo, po.om,1.4 and Nw ,y in Equation (7.6).
- 7. In the application of Equation (3.17), what irradiation period was used in determining the effect of the power history on the dosimeter response? If the power history used in Equation (3.17) was averaged over an irradiation interval l larger than one month, provide an estimate of the effect of this approximation on the dosimeter response.
- 8. Equations (7.1)-(7.5) assume that the contribution to the measurement error frorn a given error source is equal to the error in the source. For example, the error in the measurement due to dimensional errors is taken to be the same as the error in the dimensions. Since this is not generally valid, standard uncertainty analyses relate the error source and resulting measurement error using sensitivity factors which express the sensitivity of the measurement to errors in the source variable.
These sensitivity factors can be significantly different than unity when the measurement has a weak nonlinear dependence on the source variable (e.g., in the case of the exponental dependenx of the absorption correction on the dosimeter thickness). These sensitivity factors should be included in the uncertainty l' equations.
- 9. Provide the value and basis for the weighting p.,, used in Equation (7.13). Is the J value the same as used in Equation (7.6)?
ENCLOSURE
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- 10. Please define the denominator in Equation (7.10).
i 11, - Because of the strong fluence attenuation between the core'and vessel, the dosimeter response is very sensitive to the methods and data used in'these l calculations. As a result, typical pressure vessel fluence calculations are expected i_ to provide an accuracy of~ 15% when predicting (> l-MeV) dosimeter response.
, The major contributors to this uncertainty are the (1) relative core / vessel / dosimeter geometry (2) nuclear cross sections and fission spectra (3) determination of the core neutron source (4) methods and modeling l
approximations and (5) the Equation (3.17) adjustment for irradiation and decay times. In view of the fact that the observed M/C uncertainty is substantially less than 15 %, provide an explanation for this reduced M/C uncertainty. Have any adjustments (other than those explicitly identified in the report) been made to j improve the M/C agreement?
- 12. In the third column of Table A-2, the value of 1-C/M is provided instead ofco ,
Provide the plant dependent value of o cw
- 13. Were the benchmark data-base capsule and cavity measurements of Table A-1
- which are identified by plant actually made at the assigned plant, or were the dosimeters / capsules from the assigned plant irradiated in a different (or surrogate) plant? Please identify any measurements that were not actually installed and measured at the indicated plant.
- 14. The BAW-2241-P fluence methodology does not include the analytic determination (based on numerical sensitivities) of the fluence calculation uncertainty as described in DG-1053. Please identify any other calculation or measurement differences between the proposed methodology and the guidance of DG-1053.
- 15. The calculational perturbation factors of Appendix-C were determined using the BUGLE-80 fluence methodology rather than the most recent BUGLE 93 Semi Analytic approach. What is the effect on the M/C data-base and associated biases and uncertainties of using this earlier methodology?
- 16. The standard deviation of the M/Cs (fmm Cne overall average M/C) in the Appendix-A data-base appears to be alm 9st a factor of two larger than the value given in the text (on p. 7-33). Please provide an explanation for this difference.
- 17. The calculation uncertainty is determined by combining the measurement L uncertainty, ou, and the standard deviation, ocu, of Equation (7.16). However,it is not evident that these_ two quantities refer to the determination of the same response (as required). For example, it appears that ou refers to the uncertainty in ,
the measurement of a specific nuclide (e.g., Ni-58(n,p)) while ocu refers to the l 1
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?
i, .
3 C/M dev' . tion for the average of all nuclides of a given capsule. Please explain this appar?nt discrepancy and justify any differences in the response being used in the definitions of ou and o cu. i
- 18. BA"I 2241-P states that the BUGLE-93 calculations of one of the dosimeter
, responses is erroneous (p. 7-29) and that the BUGLE-93 calculated C/Ms for this type of dosimeter have been removed from the analysis (p. 7-31). In addition, it is stated (p. 6-4) that this dosimeter has "special problems.". What is the C/M bias for this type of dosimeter and is this improved by the use of a BUGLE-93 (rather than CASK) photo-fission correction?
1 l 19. Recent calculations described in NUREG/CR-6453 suggest that the BUGLE-93 .
l
~ cross section library results in an underprediction (relative to BUGLE-96 and !
SAILOR-95) of the Fe-54, Ni-58, U-238 and Np-237 cavity dosimeter reaction l rates of 1%,2%,4%, and 10%, respectively. (The prediction of the in-vessel l dosimeter reaction rates for the three libraries agree to within 1%.) In view of the j difference between these libraries, please review and update the FTl M/C data i l base and methodology, as necessary. Will this update allow the inclusion of the L' threshold dosimeter measurements that were excluded?
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