ML18058B872
| ML18058B872 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 06/10/1993 |
| From: | Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML18058B873 | List: |
| References | |
| NUDOCS 9306150375 | |
| Download: ML18058B872 (4) | |
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/llllCHlliAN'S PROliRESS Pa~dn~N'f~:r Pf§'gj7780 Blue Star Memorial Highway, Covert, Ml 49043 Nuclear Regulatory Commission Document Control Desk Washington~ DC 20555 GB Slade General Manager.
DOCKET 50-255 - LiCENSE DPR PALISADES PLANT - 10CFR50.61 PRESSURIZED THERMAL SHOCK - REACTOR VESSEL NEUTRON FLUENCE - ADDITIONAL INFORMATION Consumers Power Company's June 5, 1992 submittal, "Palisades Plant -
10CFR50.61 Pressurized Thermal Shock - Revised Projected Values of RTprs For Reactor Beltline Material," concluded that the Palisades reactor vessel materials would not exceed the screening criteria specified in the pressurized thermal shock rule (10CFR50.61) before the end of licensed life in year 2007.
At the time the report was submitted, evaluation of dosimetry which had been located in the reactor vessel and in the reactor vessel cavity during fuel cycle 9 had not been completed.
This letter transmits Westinghouse report, WCAP-13534 (Rev. 2), "Palisades Nuclear Plant Reactor Vessel Neutron Fluence Measurement Program for Consumers Power Company, Results to End of Cycle 9" (Attachment 2), which contains the results of the reactor cavity neutron dosimetry measurements carried out during fuel cycles 8 (November 29, 1988 through September 14, 1990) and 9 (March 15, 1991 through February 6, 1992) and the in-vessel dosimetry capsule measurement'performed during cycle 9.
Previously analyzed W-290 surveillance capsule dosimetry measurements have also been included.
It should also be noted that Attachment 4 (Westinghouse report WCAP-13348) in our June 5, 1992 submittal contained flux calculations using discrete ordinates methods with S8 quadrature and a P3 angular-scattering of cross-sections.
In the enclosed WCAP-13534 report, Westinghouse has utilized a higher order of the quadrature (or increase in the number of scattering angles, namely S16 with P3 angular-scattering of cross-sections) for the cycle 8 and cycle 9 flux calculations. However, in general we have found that there are only minor changes in the calculated fast neutron flux (E > 1.0 MeV) reported in our June 5, 1992 report and those reported in WCAP-13534 (See - Table 1).
WCAP-13534 fortifies our previous conclusion that, for the Palisades reactor vessel, calculated fluence values are larger than measured fluence values.
As reported in WCAP-13534, calculated results are higher than the four sets of iin*dependent measurements, i.e., W-290 survei 11 ance capsule measurements,
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replacement in-vessel dosimetry capsule measurements during cycle 9 and reactor cavity dosimetry measurements for cycles 8 and 9.
Consequently, we conclude that fast flux calculations have been conservative with respect to both the standard out-in core loading schemes (from cycles 1 through 7) and the low leakage core design for cycles 8 and 9.
As a result of the revised flux calculations for cycles 8 and 9 reported in WCAP-13534, the accumulated fluence by the end of cycle 9 has been recalculated for the beltline materials.
The revised fluence values are compared to those reported in our June 5, 1992 report in Table 2 (Attachment 1). Since there are no significant changes from the fluence values reported in our June 5, 1992 submittal, there is no need to revise the fluence values reported at that time.
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Gerald B Slade General Manager CC Administrator, Region Ill, USNRC NRC Resident Inspector - Palisades Attachments.
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ATTACHMENT 1 Consumers Power Company Palisades Plant Docket 50-255 PRESSURIZED THERMAL SHOCK REACTOR VESSEL NEUTRON FLUENCE June 10, 1993 1 Page
Table 1 Flux {x ElO n/cm2-sec) {E > 1.0 MeV)
Location Cycle 8 Cycle 9 0 degre~s, axial weld 2.15 2.08 (2.10)
(2.09) 30 degrees, axial weld 2.34 2.00 (2.28)
( 1. 99) 16 degrees, peak {plate 4.89 3.06 and circumferential
{4.76)
{3.05) weld)
Flux values are from WCAP-13534, Table 8-4 multiplied by a bias factor of 1.06 or corresponding fiche for the outer DOT run.
Flux values in parenthesis are from Table 3-1 in Consumers Power Company's June 5, 1992 submittal.
Table 2 Fluence {x El9 n/cm2) {E > 1.0 MeV) location Fluence {EOC-9)
Fluence rate 0 degrees, axial weld 1.17
.. 066 (1.17)
(. 066) 30 degrees, axial weld 1.19
.063 (1.19)
(. 062) 16 degrees, peak {plate 1.61
.097 and circumferential
{ 1. 60)
{. 097) weld)
Fluence values [at the end-of-cycle 9] are re-calculated using the data from WCAP-13534 {Rev. 2).
Fluence values in parenthesis are from Table 3-2 in Consumers.
Power Company's June 5, 1992 report.
Fluence rates are re-calculated using the cycle 9 flux from WCAP-13534 {Rev.2).
Fluence rates in parenthesis are from Section 4-1 in Consumers Power Company's June 5, 1992 report.