ML092380318
| ML092380318 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 08/25/2009 |
| From: | Office of Nuclear Reactor Regulation, Plant Licensing Branch IV |
| To: | |
| Hall, J R, NRR/DORL/LPL4, 301-415-4032 | |
| Shared Package | |
| ML092380294 | List: |
| References | |
| TAC ME0698, TAC ME0699, TAC ME0700, TAC ME0703, TAC ME0704, TAC ME0705 | |
| Download: ML092380318 (3) | |
Text
REQUEST FOR ADDITIONAL INFORMATION ARIZONA PUBLIC SERVICE COMPANY, ET. AL.
PALO VERDE NUCLEAR GENERATING STATION, UNITS 1, 2 AND 3 DOCKET NOS. STN 50-528, 50-529, AND 50-530 LICENSE AMENDMENT REQUEST AND EXEMPTION REQUEST TO RELOCATE THE PRESSURE/TEMPERATURE LIMITS AND LOW TEMPERATURE OVERPRESSURE PROTECTION LIMITS TAC NOS. ME0698, ME0699, ME0700, ME0703, ME0704 AND ME0705 By letter dated February 19, 2009 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML090641014), Arizona Public Service Company (APS) submitted a license amendment request and an associated request for exemption for Palo Verde Nuclear Generating Station (PVNGS), Units 1, 2, and 3.
The proposed amendment would relocate the reactor coolant system pressure and temperature (P/T) limits and the low temperature overpressure protection enable temperatures from the current Technical Specifications (TSs) to the PVGNS Technical Requirements Manual, which would be subject to the controls identified in new TS 5.6.9. The requested exemption from 10 CFR 50, Appendix G, would allow APS to apply the methods of NRC-approved topical report CE NPSD-683-A, Revision 6, for calculating KIM values to the calculation of P/T limits, in lieu of the methods required by Appendix G.
The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided and determined that the additional information specified below is needed for the staff to complete its evaluation of the amendment request and the exemption request.
(1)
Appendix G of Part 50 of Title 10 of the Code of Federal Regulations (10 CFR Part 50) requires reactor pressure vessel pressure-temperature (P-T) limits to be generated for heatup, cooldown, criticality, and hydrostatic and leak tests. Please demonstrate that the P-T limits on pages TA-6 and TA-7 of the proposed PVNGS Pressure and Temperature Limits Report satisfy this requirement by addressing the following:
- a. Although the WCAP-16835 report, Palo Verde Nuclear Generating Station Units 1, 2 and 3; Basis for RCS Pressure and Temperature Limits Report, stated that the composite P-T limits for PVNGS Units 1, 2, and 3 includes core critical values, the proposed PVNGS P-T limits do not seem to support it. Please clarify and revise the P-T limits, if necessary.
- b. Unlike the current P-T limits, the proposed P-T limits now have part of hydrostatic test and normal operation curves on the left hand side of the lowest service temperature line of 153.2 ºF. Please demonstrate that the proposed P-T limits are clear for the operators to use.
- c. Criterion 1b of Table 1 of 10 CFR Part 50, Appendix G for the hydrostatic test results in a minimum test temperature of 163.2 ºF. This is more limiting than the
lowest service temp 153.2 ºF marked in the proposed P-T limits. Again, please demonstrate that the proposed P-T limits are clear for the operators to use considering that a critical limiting temperature is not shown there.
(2)
Please confirm that the 2-dimensional finite element method (FEM) model that you used to calculate the applied stress intensity factor, KIM, at a pressure of 1000 psi is plant-specific. If a generic FEM model was used, explain how the results from such a model are applicable to PVNGS Units 1, 2 and 3.
(3)
Table 5-2 of the WCAP-16835 report shows that an identical pressure of 1195.2 psia is obtained at the temperature of 153.2 °F for cooldown rates from 10 °F per hour to 100
°F per hour, indicating the cooldown thermal stress intensity factor (KIT) values are zero at a specific point during the transient for P-T limit calculations regardless of the cooldown rates. However, Figure 5-8 shows different KIT values at the temperature of 153.2 °F for different cooldown rates. Please explain, at what point during the cooldown can the cooldown KIT values of Figure 5-8 be used to arrive at the P-T limits tabulated in Table 5-2 for the cooldown transient and, at what point during the heatup can the heatup KIT values of Figure 5-6 be used to arrive at the P-T limits tabulated in Table 5-1 for the heatup transient.
(4)
In WCAP-15589, Analysis of Capsule 38° from the Arizona Public Service Company Palo Verde Unit 1 Reactor Vessel Radiation Surveillance Program, two surveillance data from Capsule 38° were labeled as intermediate shell plate M-6701-2 and used in the chemistry factor calculation for this plate. However, in WCAP-16374, Analysis of Capsule 230° from the Arizona Public Service Company Palo Verde Unit 1 Reactor Vessel Radiation Surveillance Program, the two surveillance data from Capsule 38° are dropped from the chemistry factor calculation for intermediate shell plate M-6701-2.
No explanation was given in the report, except a statement on page D-3 which may allude to a possible misidentification of specimens: The lower shell plate M4311-1 also has surveillance data but only one set up to this point (from Capsule 38°), thus it will not be evaluated. Please confirm your misidentification of surveillance specimens and explain the cause(s) of the error. Or, if correct, explain the basis of discarding the surveillance data from Capsule 38° in calculating the chemistry factor for intermediate shell plate M-6701-2.
(5)
Section 3.2.1 of WCAP-16835 discusses the assumptions and results for the analysis of the mass and energy addition events. Provide a discussion to demonstrate that the analysis for these events is a bounding analysis over the operating temperature and pressure ranges of the LTOP system in terms of the minimum margin between the allowable P/T limits and the calculated peak pressure during transients of the two events.
(6)
In the middle portion of page 3-2 of WCAP-16835, it states that [d]ecay heat, with two sigma uncertainty, is at value consistent with the earliest time after shutdown that the transient can occur. Discuss the decay heat model and specify the decay heat value used in the analysis of the mass and energy addition events, and justify the adequacy of the model and value of the decay heat.
(7)
Paragraph 3 of Section 3.2.1.2 discusses the HPSI flow rate and a low temperature for the supply water used in the analysis of the mass addition event. Specify the low temperature of the supply water used in the analysis and justify that it will result in the greatest rate of mass addition over the applicable temperature range.
(8)
Section 3.2.1.3 indicates that the energy addition analysis assumes the initial RCS pressure of 435 psig. Specify the allowable operating pressure range for the LTOP system and show that the analysis with the assumed initial RCS pressure of 435 psig is a limiting analysis, resulting in a highest peak pressure during the energy addition transient.
(9)
Section 3.3.3.3 of CENPSD-683-A states that for the LTOP analysis, the pressure drop in the piping from the hot leg to the SDC relief valve inlet and the elevation head from the valve to the pressurizer must be considered in the adjustment of the peak pressure at the valve inlet to the pressurizer. Section 3.3.4 states that for the energy addition analysis, fluid properties and heat transfer coefficients should be determined at the highest RCS temperature. Address compliance with the above guidance specified in CENPSD-683.
(10) Section 3.2.1.1 of WCAP-16835 indicated that the capacity of the SCS relief value is 5635 gpm at 10% accumulation of the valve lift point of 467 psig. The corresponding relief valve capacity of 4000 gpm is stated in Section 5.2.2.11.2.3 (page 5.2-39) of the updated safety analysis report, Revision 13, for the Palo Verde plant. Clarify the inconsistency of the above SCS relief valve capacities.