ML030920020

License Amendment Request 187 to the Kewaunee Nuclear Power Plant TS

ML030920020
Person / Time
Site:	Kewaunee
Issue date:	03/19/2003
From:	Coutu T Nuclear Management Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC-03-031, TAC MB5718
Download: ML030920020 (9)

Text

Committed to N MclerExce Kewaunee Nuclear Power Plant Operated by Nuclear Management Company, LLC NRC-03-031 10 CFR 50.90 March 19, 2003 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 KEWAUNEE NUCLEAR POWER PLANT DOCKET 50-305 LICENSE No. DPR-43 LICENSE AMENDMENT REQUEST 187 TO THE KEWAUNEE NUCLEAR POWER PLANT TECHNICAL SPECIFICATIONS (TAC NO. MB5718)

References:

Letter from Thomas Coutu (NMC) to Document Control Desk (NRC), "NMC Responses To NRC Request for Additional Information Concerning License Amendment Request 187 to the Kewaunee Nuclear Power Plant Technical Specifications (TAC NO. MB5718)," dated February 27, 2003.

The Nuclear Management Company, LLC, (NMC) submitted a response to the Nuclear Regulatory Commission (NRC) request for additional information (RAI) concerning License Amendment Request (LAR) 187 (reference 1) to the Kewaunee Nuclear Power Plant (KNPP)

Technical Specifications (TS) revising KNPP TS to allow transitioning to Westinghouse 422V+

nuclear fuel.

On review of the response NMC submitted for question 58, NMC has determined additional information is necessary to fully answer this question. Attachment 1 is NMC revised response to question 58.

If there are any comments or questions concerning this request please contact Mr. Gerald Riste, of my staff, at (920) 388-8424.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on March 19, 2003.

Thomas Coutu Site Vice-President, Kewaunee Plant GOR cc-US NRC, Region III US NRC Senior Resident Inspector Electric Division, PSCW Enclosure-RAI Question 58 Response N490 Highway 42

• Kewaunee, Wisconsin 54216-9510 ODA Telephone-920 388.2560

58.

Because it is possible for one fuel type to be POT-limiting, and another to be oxidation-limiting, provide a commitment to report LOCA analysis results for all fuel types (represented in a significant number of assemblies), per 10 CFR 50.46 (a)(3).

Response

The Westinghouse 422V+ and Framatome ANP fuel designs were both evaluated and shown to satisfy the 10 CFR 50.46 acceptance criteria for large break and small break LOCA. The assessments were performed at the uprated power level of 1772 MWt and were consistent with the core designs analyzed for Attachment 4 to LAR 187 (Reference 1) and future expected KNPP reload cores. The results are presented in Tables 58-1 and 58-2 below.

The POT and oxidation assessments are discussed in more detail below.

Large Break LOCA The values reported in Table 58-1 were generated consistently with the NRC-approved Best-Estimate LOCA (BELOCA) methodology (Reference 2). For example, the oxidation values are calculated for a transient that has a peak cladding temperature in excess of the 95th percentile value, and are reported for the fuel that has the maximum transient oxidation (i.e., fresh fuel).

For Kewaunee, the selected transient was a calculation performed for a full core of Westinghouse fuel, which was shown to bound a mixed core configuration as discussed below.

Mixed core assessments were performed using two WCOBRA/TRAC calculations. The first modeled the hot rod/assembly as fresh Westinghouse 422V+ fuel surrounded by partially depleted Framatome ANP fuel. The second modeled the hot rod/assembly as partially depleted Framatome ANP fuel surrounded by Westinghouse 422V+ fuel. The POT for both mixed core scenarios was less than that calculated using a model representing a full core of Westinghouse fuel.

The Framatome ANP fuel was analyzed in the second WCOBRA/TRAC calculation as though it would operate at the same peaking factors as the Westinghouse fuel (FQ = 2.50, FdH = 1.80).

That calculation showed that the partially depleted Framatome ANP fuel was non-limiting with respect to POT by 1250F at the limiting second reflood peak. However, the Framatome ANP fuel will continue to have peaking factor limits of FQ = 2.35 and FdH = 1.70. Based on power distribution studies performed for Westinghouse fuel that are applicable to Framatome ANP fuel, it is estimated that the lower peaking factors would reduce POT for the Framatome ANP fuel by 1300F. This information was used to determine the 95th percentile POT reported in Table 58-1 for the Framatome ANP fuel (Framatome ANP fuel POT = 20840F - 1250F - 130'F =

18290F). This is considered to be a conservatively high value for POT, as the burnup assumed for the Framatome ANP fuel was much less than what was actually the case for the RTSR core designs. Specifically, a burnup of 3500 MWD/MTU was assumed for the Framatome ANP fuel in the second WCOBRA/TRAC calculation as compared to an actual burnup in the first RTSR transition core design that was greater than 18000 MWD/MTU at the beginning of cycle. Initial stored energy decreases significantly (on the order of 3000F) for high powered fuel rods in their first cycle of operation, due to closing of the pellet-cladding gap. The reduction in POT for Framatome ANP fuel due to this effect was therefore conservatively accounted for in the mixed core calculation by of the use of the conservatively low burnup.

The substantial similarities in design between the Framatome ANP and Westinghouse fuel allow the transient oxidation corresponding to the POT for the Framatome ANP fuel to be evaluated based on calculations with Westinghouse fuel that resulted in PCTs close to the Framatome ANP fuel POT value. Transient oxidation results for six cases with POT in the range of 1810-1870°F were reviewed, and the reported transient oxidation value for Framatome ANP fuel bounds all cases.

The footnote to Table 58-1 also reports the maximum expected total of the normal operation (pre-transient) and LOCA transient oxidation, for any point in burnup. This maximum value corresponds to end of life conditions, and is almost entirely attributable to pre-transient oxidation. At this point in burnup, the reduction in initial stored energy due to pellet-cladding gap closure, and the reduction in achievable power due to depletion of fissionable isotopes, results in peak cladding temperatures that are too low for LOCA transient oxidation to occur to any significant extent.

Figure 58-1 shows the PCT transients for a full core of 422V+ fuel compared to a transition core with partially depleted Framatome ANP fuel surrounded by 422V+ fuel. This calculation was performed using the reference transient conditions as defined by the Westinghouse methodology in WCAP-14449-P-A. Figures 58-2 and 58-3 compare the RCS pressure transients for those two runs, for the entire transient, and for the reflood portion, respectively.

Figure 58-4 compares the hot assembly collapsed liquid level. It can be seen that the core configuration has little effect on the RCS pressure or hot assembly collapsed liquid level. The reflood PCTs from Figure 58-1 are 1 7630F for the full core 422V+ fuel calculation, and 1 6381F for the calculation with partially depleted Framatome ANP fuel surrounded by 422V+ fuel.

Small Break LOCA In the SBLOCA analysis, it was determined that the PCT calculated for a full core of Westinghouse 422V+ fuel bounds the transition cycles. Given the low SBLOCA PCT of 10300F, cladding oxidation during the transient is not a concern. The footnote to Table 58-2 also reports the maximum expected total of the normal operation (pre-transient) and transient oxidation, for any point in burnup. As with the large break LOCA results, this maximum oxidation value corresponds to end of life conditions. It is entirely attributable to pre-transient oxidation.

Framatome ANP Fuel Pre-Transient Oxidation Pre-transient oxidation for the Framatome ANP fuel has also been addressed through fuel rod design requirements which limit the maximum pre-transient oxidation to <13.2% equivalent cladding reacted (ECR) on a 95/95 basis. The maximum calculated pre-transient oxidation for the FANP fuel through the final transition cycle is <10.6% ECR on a 95/95 basis, appreciably less than 13.2% ECR. Note that maximum pre-transient oxidation and maximum transient oxidation cannot occur in the same fuel rod. Therefore, the summation of the maximum pre-transient and maximum transient oxidation values is not required to meet the 17% maximum cladding oxidation limit of 10 CFR 50.46.

Reference

1. Letter from Mark E. Warner (NMC) to Document Control Deck (NRC), "License Amendment Request 187 to the Kewaunee Nuclear Power Plant Technical Specifications, Conforming Technical Specification Changes for Use of Westinghouse VANTAGE + fuel," dated July 26, 2002

2. S. M. Bajorek, et al., WCAP-1 2945-P-A (Proprietary), Westinghouse Code Qualification Document for Best-Estimate Loss-of-Coolant Accident Analysis, Volume I, Rev. 2, and Volumes 1l-V, Rev. 1, and WCAP-14747 (Non-Proprietary), March 1998.

Table 58-1 LBLOCA Fuel Cladding Results Result Value Criteria 50th Percentile PCT (OF)

<1760 (all fuel)

N/A 95th Percentile PCT (OF)

<2084 (Westinghouse fuel)

<2200

<1829 (Framatome ANP fuel) l Maximum Cladding Oxidation during

< 8.44 (Westinghouse fuel)

<17 LOCA Transient (%)'

< 4.0 (Framatome ANP fuel)

Maximum Hydrogen Generation (%)

<0.74 (all fuel)

<1 Coolable Geometry Core remains coolable Core remains coolable Long-Term Cooling Core remains cool in long Core remains cool in long term term Note:

1. The maximum total oxidation of any fuel in the core, including pre-transient oxidation, is estimated as < 15%.

This maximum value would be for fuel that is ready to be discharged.

Table 58-2 SBLOCA Fuel Cladding Results High Tavg 2 Low Tavg Result Criteria 2-Inch 3-Inch 4-Inch 3-Inch Peak Clad Temperature (OF)

<2200 916 1030 938 861 Peak Clad Temperature N/A 11.00 11.00 9.75 11.00 Elevation (ft)

Maximum Cladding

<17.0

<0.01 0.01

<0.01

<0.01 Oxidation During LOCA Transient (%)3 Maximum Local Zirc-Water N/A 11.25 11.00 10.25 11.25 Reaction Elevation (ft)

Total Zirc-Water Reaction

<1.0

<1.0

<1.0

<1.0

<1.0

(%)

Hot Rod Burst Time (sec)

N/A No burst No burst No burst No burst Hot Rod Burst Elevation (ft)

N/A N/A N/A N/A N/A Reactor Core Rated Thermal Power' 1772 MWt Notes:

1. 0.6% is added to the core thermal power to account for calorimetric uncertainties.

2. A high Tavg 6-inch break case was performed resulting in no core uncovery.

3. The maximum total oxidation of any fuel in the core, including pre-transient oxidation, is estimated as <

15%. This maximum value would be for fuel that is ready to be discharged.

Full Core of Westinghouse 422V+

-- -- Partially Depleted FRA/ANP Fuel Surrounded by 422V+

1800 1600--

1400- - - -______------

t - - - - - - - - -----

1200

-_+___

-_+_ _________

E E 100 - --------------I------------ ------------ I 6 0 0 - - --- - -- -- -- --- -- -- -- - -- ---- -- --- -- -- -- -- - -- -- - ---

I

' Sl I

I, 400

_+ _ _ __ t + __ _ _ _

2 0

20 I

l

}

l l

l l

l l

a Time (s)

Figure 58-1: Peak Cladding Temperature Comparison

I Full Core of Westinghouse 422V+

-- -- Partially Depleted FRA/ANP Fuel Surrounded by 422V+

2500 2

0 0 0 -

I C

1500 -_

_ __+-

_+-______

+_____

cl) con cn Q)

I

0)

I I00 5

1000

-+-------_____

I\\

ii I

I 500~~~~~~

I_\\

_________+____

0 Time (s)

Figure 58-2: Full Transient RCS Pressure Comparison

Full Core of Westinghouse 422V+

Partially Depleted FRA/ANP Fuel Surrounded by 422V+

60 L

X E

a l-----

0

+

I I

20 Figure 58-3: Reflood RCS Pressure Comparison

Full Core of Westinghouse 422V+

Partially Depleted FRA/ANP Fuel Surrounded by 422V+

12 10

-a

-J

• 6

.2-a, 0~

cn

-2 2

0 Time (s)

Figure 58-4: Hot Assembly Liquid Level Comparison