ML20070P772
| ML20070P772 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 05/05/1994 |
| From: | Hutchinson C ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-92-01, GL-92-1, GNRO-94-00073, GNRO-94-73, NUDOCS 9405120214 | |
| Download: ML20070P772 (4) | |
Text
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May 5, 1994 U.S.
Nuclear Regulatory Commi<,sion Mail Station P1-37 Washington, D.C.
20555 Attention:
Document Control Desk
Subject:
Grand Gulf Nuclear Station Docket No. 50-416 License No. NPF-29 Response to Generic Letter 92-01 Containing Revised Information Concerning Reactor Vessel Structural Integrity GNRO-94-00073 Gentlemen:
By letter dated April 6, 1994, the Nuclear Regulatory Commission requested Grand Gulf Nuclear Station to verify the information entered in the computerized Reactor Vessel Integrity Database (RVID) for accuracy.
A response was required only if inconsistencies were identified.
Attached are Grand Gulf's comments on the information contained in the RVID.
If you have any questions or require additional information, please contact this office.
Yours truly k,,'
'h CtH/ MAD /amb attachment:
Comments on Information Entered into the RVID Database cc:
(See Next Page) o r 0 "l 19
., 4 9405120214 940505
- hf PDR ADOCK 05000416 l gg p
May 5, 1994 GNRO-94/00073 Page 2.of 3 cc:
Mr.
R.
H. Bernhard (w/a)
Mr.
H.
W. Keiser (w/a)
Mr.
R.
B. McGehee (w/a)'
Mr.
N.
S.
Reynolds (w/a)
Mr.
H. L. Thomas (w/o)
Mr. Stewart D. Ebneter (w/a)
Regional Administrator U.S.
Nuclear Regulatory Commission Region II 101 Marietta St.,
N.W.,
Suite 2900 Atlanta, Georgia 30323 Mr.
P.
W.
O'Connor, Project _ Manager (w/2)
Office of Nuclear Reactor Regulation.
U.S.. Nuclear Regulatory Commission Mail Stop 13H3 Washington, D.C.
20555
5
. to GNRO-94/00073 Page 1 of 2 Comments to Reactor Vessel Integrity Database 1.
The Summary File for Pressure-Temperature Limits identifies the ID neutron fluence at EOL/EFPY as 3.14E18.
The summary file references assumed a fluence of 2.11E18 at the T/4 location.
The ID surface fluence information in the' summary file is the staff determination of the fluence at the ID surface.
Per Reg Guide 1.99, Rev 2, neutron fluence at any depth in the vessel wall is calculated as follows:
f = fsurf (e -0.24x)
(Reg Guide Eq. 3)
GGNS had previously identified the vessel wall thickness as 6.625".
Using the above T/4 neutron fluence and vessel wall thickness of 6.625", the ID neutron fluence is 3.14E18 as "back calculated" by the staff.
However, review of GGNS documentation indicates that, for conservatism, the T/4 fluence levels at GGNS were calculated using the vessel wall thickness without the' cladding thickness (that is, 6.625" minus the cladding thickness of 0.1875").
This gives a vessel wall thickness of 6.4375".
The actual ID surface fluence determined from flux wire dosimetry measurements at GGNS is 3.11E18.
Using the vessel wall thickness without cladding and the ID surface fluence level of 3.11E18,.the T/4 fluence is 2.11E18.
It is requested that the NRC Summary File be modified to show an ID Neutron Fluence at EOL/EFPY of 3.11E18.
2.
The Summary File references indicate that the staff estimated the Ni content of weld 626677 at 1.00% per RG 1.99, Rev.
2.
- However, the Summary File indicates a Ni content of 1.04% for this weld.
It was determined that this is the value given in the GGNS FSAR which is based on actual Certified Material Test Report _(CMTR) chemical analysis.
It is requested that the reference note for weld 626677 be deleted.
3.
The Summary File indicates the Chemistry Factor for weld 626677 is 20.
GGNS has reviewed calculations and the chemistry factor information in Table 1 of RG 1.99, Rev. 2 and has determined that the correct Chemistry Factor for weld 62667 is 41.
This is.the Chemistry Factor that was used by GGNS for the development of the ART value that is documented in the GGNS FSAR~for this weld.
It is' requested that the Chemistry Factor for weld 626677 be' changed to 41.
l
.- to GNRO-94/00073 Page 2 of 2 4.
The Summary File identifies the unirradiated Upper Shelf Energy j
USE for the beltline materials based on information provided in the GGNS FSAR.
The NPE review of the original ART calculations, the beltline material CMTRs, the GGNS FSAR and the data in the summary file has identified the following:
4.1 The GGNS FSAR contains a typographical error on the USE values (values at 212 F) for plate heat no A1224-1.
The FSAR records USE values of 122, 177 and 188.
The staff used these numbers and determined that an average USE of 162.
The actual values recorded in the CMTR are 122, 117 and 118.
This would give an average USE of.119.
(Note that the GGNS calculations addressed above were based on the lowest of the three USE values recorded in the CMTR, not the incorrect values in the FSAR).
It is requested that the average value for plate A1224-1 be changed to 119 4.2 The unirradiated Upper Shelf Energy. (USE) recorded in the Summary File was determined by the staff.
The Summary File USE is the average of the three USE values contained in the FSAR for each material.
The GGNS USE calculations were conservatively based on the lowest of the three USE values and an assumed higher predicted fluence than actually determined (2.4E18 versus 2.11E18).
This assumed fluence resulted in a predicted percent decrease in USE of 14% as determined from RG 1.99, Rev.
2, Figure 2.
When combined with'the conservative unirradiated USE values,'T/4 EOL USE values determined by GGNS are below those predicted by the staff.
The values are still above 50 ft-lbs as noted in Reference 2 and the GGNS FSAR.
The values also bound the values determined by the staff.
liowever, the values are not consistent with those documented by the staff in the Reference File.
Grand Gulf Nuclear Station has reviewed the average unirradiated USE values determined by the staff and, except as noted above for plate A1224-1, agrees with the average t
USE values documented by the staff in the Reference File.
Using RG 1.99, Rev.
2, Figure 2, for a fluence of.2.11E18, the predicted percent decrease in USE was conservatively estimated to be 12% which gives T/4 USE at EOL values consistent with those in the Summary File.
It is concluded that no additional action is required for this item.
_