ML032110465

Realistic Large Break Loss of Coolant Accident Analysis Results for Proposed TS Changes & Exemption Request for Use of Framatome Anp Advanced Mark-BW Fuel

ML032110465
Person / Time
Site:	North Anna
Issue date:	07/18/2003
From:	Grecheck E Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
03-407, NLOS/ETS
Download: ML032110465 (18)

Text

VIRGmiA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 July 18, 2003 U. S. Nuclear Regulatory Commission Serial No.03-407 Attention: Document Control Desk NLOS/ETS Washington, D.C. 20555 Docket Nos. 50-338 50-339 License Nos. NPF-4 NPF-7 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2 REALISTIC LARGE BREAK LOSS OF COOLANT ACCIDENT (LBLOCA) ANALYSIS RESULTS FOR THE PROPOSED TECHNICAL SPECIFICATIONS CHANGES AND EXEMPTION REQUEST FOR USE OF FRAMATOME ANP ADVANCED MARK-BW FUEL In a March 28, 2002 letter (Serial No.02-167), Virginia Electric and Power Company (Dominion) requested an amendment to Facility Operating License Numbers NPF-4 and NPF-7 and associated exemptions from 10 CFR 50.44 and 10 CFR 50.46 for North Anna Power Station Units 1 and 2. The amendments and exemptions will permit North Anna Units 1 and 2 to use Framatome ANP Advanced Mark-BW fuel. This fuel design has been evaluated by Framatome and Dominion for compatibility with the resident Westinghouse fuel and for compliance with fuel design limits. Subsequent to the March 28, 2002 letter, Dominion submitted supplements on REFLOD3B (July 25, 2002, Serial No. 02-167B), small break LOCA (August 2, 2002, Serial No. 02-167C), and large break LOCA (August 16, 2002, Serial No. 02-167D). Based on further discussions with the NRC, Dominion withdrew the LBLOCA and REFLOD3B submittals (November 15, 2002, Serial No. 02-167E) and agreed to submit a RLBLOCA analysis, and a revised small break LOCA (SBLOCA) analysis. Dominion submitted a supplement that provided the RLBLOCA analysis results for North Anna Unit 2 (May 6, 2003, Serial No.03-313). In addition, Dominion submitted the revised SBLOCA analysis results for North Anna Units 1 and 2 (May 27,2003, Serial No.03-245). to this letter provides the RLBLOCA results for Advanced Mark-BW fuel in North Anna Unit 1. The RLBLOCA information is presented in the form of changed pages to the proprietary and non-proprietary supplements provided in our May 6, 2003 letter (specifically, report Section 7.0). Although marked as proprietary for inclusion into the May 6, 2003 proprietary version, the attached pages contain no proprietary information. For completeness, the LOCA Summary in Section 7.4 incorporates the conclusions for the RLBLOCA Unit 1 analysis and those developed in our May 27, 2003 letter for SBLOCA. Please note that the submittal of the RLBLOCA results for North Anna Unit 1 is the final submittal planned for this license amendment.

Af

To support the use of Framatome Advanced Mark-BW fuel in North Anna Unit 2, Cycle 17, we respectfully request the NRC to complete their review and approval of the license amendment and exemptions by September 30, 2003. We appreciate your consideration of our technical and schedular requests. If you have any questions or require additional information, please contact us.

Very truly yours, Eugene S. Grecheck Vice President - Nuclear Support Services Commitments made in this letter: None cc: U.S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW Suite 23T85 Atlanta, Georgia 30303 Mr. J. E. Reasor, Jr.

Old Dominion Electric Cooperative Innsbrook Corporate Center 4201 Dominion Blvd.

Suite 300 Glen Allen, Virginia 23060 Commissioner Bureau of Radiological Health 1500 East Main Street Suite 240 Richmond, VA 23218 Mr. M. J. Morgan NRC Senior Resident Inspector North Anna Power Station Mr. S. R. Monarque NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 8-H12 Rockville, MD 20852

SN: 03-407 Docket Nos.: 50-338/339

Subject:

Proposed TS Change & Exempt. Request -

LBLOCA Analysis Results To Use Framatome ANP Advanced Mark-BW Fuel COMMONWEALTH OF VIRGINIA )

)

COUNTY OF HENRICO )

The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by Eugene S. Grecheck, who is Vice President -

Nuclear Support Services, of Virginia Electric and Power Company. He has affirmed before me that he is duly authorized to execute and file the foregoing document in behalf of that Company, and that the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this 18th day of July, 2003.

My Commission Expires: March 31, 2004.

-(SENotary Public ISAiL)

Realistic Large Break LOCA Analysis Results - Unit 1 Non-Proprietary Version

Non-Proprietary during the first cycle of Advanced Mark-BW operation because of the small percentage of FANP fuel that is present in the core. As the percentage of FANP fuel increases in subsequent reload cycles, the potential for flow diversion is lowered. Because provision for this flow diversion is explicitly modeled in the North Anna mixed-core RLBLOCA calculations, the expected results for subsequent reload cycles would demonstrate lower PCTs and oxidation results. Together, the results of the Reference 7-1, Appendix B study and the increase in the number of Advanced Mark-BW fuel assemblies in the core lead to the conclusion that first cycle calculations bound subsequent cycles of operation with FANP fuel.

7.2.4 Realistic Large Break LOCA Results The analyses assume full-power operation at 2,893 MWt (plus uncertainties), a steam generator tube plugging level of 12 percent in all generators, a total peaking factor (FQ) of 2.32, and a nuclear enthalpy rise factor (FiH) of 1.65. These analyses accommodate operation within specified ranges for sampled parameters: pressurizer pressure and level, accumulator pressure, temperature (containment temperature) and level, RCS average temperature, core flow, and containment pressure and temperature.

A set of fifty-nine calculations was performed for NAPS Units 1 and 2 sampling the parameters listed in Table 7.2-1. The remainder of this section provides results from those analyses.

7.2.4.1 NAPS Unit 1 Large Break LOCA Results The limiting PCT case (1,992 'F) was number 28. It is characterized in Tables 7.2-6 and Table 7.2-7. The maximum oxidation (3.8 %) and total oxidation (0.04 %) results are also reported in Table 7.2-7. The fraction of total hydrogen generated was not directly calculated; however, it is conservatively bounded by the calculated total percent oxidation that is well below the 1 percent limit. A nominal 50/50 PCT case was identified as case 30. The nominal PCT is 1,497 'F. This result can be used to quantify the relative conservatism in the limiting PCT case result. In this analysis, it is 495 'F.

The hot fuel rod results, event times and analysis plots for the limiting PCT case are shown in Table 7.2-7, Table 7.2-8, and in Figures 7.2-4 through 7.2-18, respectively. Figure 7.2-4 shows linear scatter plots of the important parameters sampled for the 59 calculations. Parameter labels appear to the left of each individual plot. These figures show the parameter ranges used in the analysis. Figures 7.2-5 and 7.2-6 show PCT scatter plots versus the time of PCT and versus break size from the 59 calculations. Figure 7.2-7 shows the maximum oxidation versus PCT for the 59 calculations. Figures 7.2-8 through 7.2-18 show important parameters from the S-RELAP5 calculation. Figure 7.2-8 is the plot of PCT independent of elevation.

7.2-7

Non-Proprietary and effectiveness of the hot leg injection is established by demonstrating that the in-vessel concentration of boric acid is below solubility limits. There is no dependency on the fuel element design since concentrations depend on ECCS injection rate, RCS geometry, and core power level. Since the Framatome ANP fuel does not alter these factors, the current evaluation remains valid and is equally applicable to Advanced Mark-BW fuel. Emergency operating procedures provide guidance to address the boric acid precipitation issue and ensure that long-term cooling is maintained.

7.2.6.4 Adherence to Long-Term Cooling Criterion Compliance with this criterion is demonstrated in the NAPS UFSAR. It is independent of fuel design. The initial phase of core cooling results in low clad and fuel temperatures. A pumped injection system, capable of re-circulation, is available and operated by the plants to provide extended coolant injection. The concentration of dissolved solids is limited to acceptable levels through the timely implementation of hot leg injection. Hence, long-term cooling is established and compliance to 10CFR50.46 demonstrated.

7.2.7 Large Break LOCA Conclusions The analyses reported herein support operations at a power level of 2,893 MWt, a steam generator tube plugging level of 12 percent in each generator, a total peaking factor (FQ) of 2.32 and a nuclear enthalpy rise factor (FAH) of 1.65. The analyses support peak rod average exposures of up to 62,000 MWd/mtU. The analyses applied no Kz restraint on axial peaking; that is, Kz is set equal to one for all core elevations. The impact of NAIF co-resident fuel on FANP Advanced Mark-BW fuel is included within the analyses-the analyses consider the initial core composition of both NAIF and Advanced Mark-BW fuel. The analysis of the Westinghouse fuel remains valid. The co-resident FANP fuel, being 2.5 psi (based on rated flow) more resistive than NAIF, will promote favorable flow diversion to NAIF, thereby improving its LBLOCA performance. Hence, the NAIF will be positively (lower clad temperature and metal-water oxidation) affected by the co-resident FANP fuel.

The results of the RLBLOCA analyses show that the limiting NAPS Unit 1 case has a PCT of 1,992 F. The limiting PCI for Unit 2 is 2,032 'F. Maximum oxidation thickness and hydrogen generation for both units are well within regulatory requirements. Discussions in Sections 7.2.5 and 7.2.6 demonstrate compliance with the coolable geometry and long-term cooling criteria.

7.2-10

Non-Proprietary Table 7.2-6: Summary of Major Parameters for Limiting NAPS Unit 1 Transient Time (hrs) l 4,242 Burnup (MWdtmtU) l9,100 Core Power (MWt) 2,940 Core Peaking () 2.144 Radial Peak (FHN) 1.65 Local Peaking (Fl) 1.07 Break Type DEGB Break Size per Side () 3.26 (-79 %)

Offsite Power Availability No Decay Heat Multiplier 0.9841 Table 7.2-7: Summary of Results for the NAPS Unit 1 Limiting PCT Case Case Number 28 PCT Temperature 1,992 F Time 95.3 seconds Elevation -9.6 ft Metal-Water Reaction

% Oxidation Maximum 3.8 %

% Total Oxidation 0.04 %

Total Hydrogen 0.62 Ibm Table 7.2-8: Calculated Event Times for the NAPS Unit 1 Limiting PCT Case Event Time (see)

Begin Analysis 0.0 Break Opens 0.0 RCP Trip 0.0 Si ACTUATION SIGNAL Issued 0.7 Start of Broken Loop Accumulator Injection 7 Start of Intact Loop Accumulator Injection 11 End of Bypass 21 Start of HHSI 28 Start of LHSI 28 Beginning of Core Recovery (Beginning of Reflood) 30 Broken Loop Accumulator Empties 38 Intact Loop Accumulators Empty 40, 40 PCT Occurs (1,992 OF)95.3 7.2-16

Non-Proprietary Break Area (fe) 0).0 1.0 2.0 3.0 4.0 5.1D Time 6" 00"500.0 000001 (hrs) 0.0 5000.0 10000.0 1 5011O.0 Core Power (MW) 2850.0 200.0 29 2800.0 2850.0 2900.0 2950.0

' ' ' I .. I .. . I Fq Peaking 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Pressurizer Pressure (psia)

.0 21 . . . . 220. .

2150.0 2170.0 2190.0 2210.0 2230.0 2250.0 2270.0 2290.0 I

Pressurizer Level (0A) 50.0 55.0 60.0 65.0 70.0 75.0 80.0 I~~~~

RCS Temperature (F) 575.0 580.0 585.0 590.0 595.0 Total Loop low (Mlbthr) 1.050Oe+08 1.1OOOe+08 1.1500e+08 12000e+08 1.250Cle+08 Accumulator Volume (ft) 95().00 960.00 970.00 980.00 990 .00 Accumulator Pressure (psia) m e. e e e m I 55 ).00 600.00 650.00 700.00 750. .00 Accumulator Temperature ., W so'mmI ' I -.

(F) Z~_Ie_~ Z * -

80.00 90.00 100.00 110.00 120.00 130.00 Figure 7.2-4: NAPS Unit 1 Scatter Plots of Operational Parameters 7.2-21

Non-Proprietary PCT vs Time of PCT 2000.0 LI III El 1800.0 0

1600.0

• U

'El 1 1400.0

• U l EOw I-tL 1200.0 0

a.

• ff 1000.0 800.0 Split Break l I i~~~~~~ 0 Guillotine Breakl 600.0 400.0 -

0.00 100.00 200.00 300.00 400.00 500.00 Time of PCT (s)

Figure 7.2-5: NAPS Unit 1 PCT versus PCT Time Scatter Plot 7.2-22

Non-Proprietary PCT vs Break Area 2000.0 , I I LI LI 1800.0 M

0LI 0

1600.0

• D

• 0 0n Ho °]

M *on C ~~~~~~LI 0

1400.0 ME aI ME LI M

L 'a 1200.0

• E#

a-1000.0 K M

U 800.0 U

600.0

• Split Break I I Guillotine Break I

400.0 L I 0.0 0O 1.00 2.00 3.00 4.00 5.00 Break Area (fI2 )

Figure 7.2-6: NAPS Unit 1 PCr versus Break Size per Side Scatter Plot 7.2-23

Non-Proprietary Maximum Oxidation 4.0 .. .. .. .

. I ..

I

• Split Break E 51 Guillotine Break 3.0 11 0

00 0 C

't 2.0 0

E Da 1.0 F in I rs 11

• E 0.0 1 _ I -_ . . . " E4 . I . I . I.

400.00 800.00 1200.00 1600.00 200 0.00 PCT (F)

Figure 7.2-7: NAPS Unit 1 Maximum Oxidation versus PCT Scatter Plot 7.2-24

Non-Proprietary 2200.0 -

2000.0 1800.0 1600.0 fl 1400.0 10

. 1200.0 a)

CO 1000.0 E

I 800.0 600.0 400.0 200.0 0.0 0.0 100.0 200.0 300.0 400.0 500.0 Time (s)

Figure 7.2-8: NAPS Unit 1 Peak Cladding Temperature for the Limiting Break (elevation independent) 70000.0 60000.0 50000.0 40000.0 ca c

0_

30000.0 2

co cc 20000.0 10000.0 0.0

-10000.0 0.0 Tim (s)

Figure 7.2-9: NAPS Unit 1 Break Flow for the Limiting Break 7.2-25

Non-Proprietary 300.0 250.0 - HA Inlet

---IR nlet 200.0 --- AC Inlet i, 150.0 O nlet 100.0 50.0

-10.00.014 IE -50.0 I ~4 S

-200.0

-300.0...

0.0 10.0 20.0 30.0 40.0 50.0 60.0 Time (s)

Figure 7.2-10: NAPS Unit 1 Early Core Inlet Mass Flux for the Limiting Break 300.0 250.0 - HA Outlet

---

IROutlet 200.0 --- AC Outlet 150.0 --- OR Outlet 100.0 l

-50.0

-200.0

-250.0 00 10.0 20.0 30.0 40.0 50.0 60.0 Time (s)

Figure 7.2-11: NAPS Unit 1 Core Outlet Mass Flux for the Limiting Break 7.2-26

Non-Proprietary 1.0 ,

0.8 C

t; e 0.6 0

0.4

---

Loop 2 0.2 I

0.0 L 0.1D 100.0 200.0 300.0 400.0 500.0 lime (s)

Figure 7.2-12: NAPS Unit 1 Void Fraction at RCS Pumps for the Limiting Break 3000.0 I - Loop 1 (broken)

---

Loop 2

--- Loop 3 e

j 2000.0

-0 Cn a:

I iL en I C, 1 000.0

!I 0.0 LL 0.0 100.0 200.0 300.0 400.0 500.0 lime (s)

Figure 7.2-13: NAPS Unit 1 ECCS Flows (includes Accumulator, HHSI and LHSI) for the Limiting Break 7.2-27

Non-Proprietary 2400.0 2200.0 2000.0 1800.0 1600.0 G 1400.0 E 1200.0 E 1000.0 800.0 600.0 400.0 200.0 0.0 0.0 10.0 20.0 30.0 40.0 50.0 60.0 Time (s)

Figure 7.2-14: NAPS Unit 1 System (Upper Plenum) Pressure for the Limiting Break 30.0 25.0 20.0

i. 15.0 v

03 10.0 5.0 0.0 L 0.0 100.0 200.0 300.0 400.0 500.0 Time (s)

Figure 7.2-15: NAPS Unit 1 Collapsed Liquid Level in the Downcomer for the Limiting Break 7.2-28

Non-Proprietary 14.0 12.0 10.0 8.0

-z

'D 6.0

-J 4.0 2.0 -

0.0 "

0.0 100.0 200.0 300.0 400.0 500.0 Time s)

Figure 7.2-16: NAPS Unit 1 Collapsed Liquid Level in the Lower Vessel for the Limiting Break 14.0 12.0 10.0 El 8.0 70 03 6.0 4.0 2.0 0.0 U 0.0 100.0 200.0 300.0 400.0 500.0 Time (s)

Figure 7.2-17: NAPS Unit 1 Collapsed Liquid Level in the Core for the Limiting Break 7.2-29

Non-Proprietary 80.0 nme' 70.0 ,1 l~~~~

F i1--uppe~eu ContainmentII 60.0 fi ~~~~-

l -- Downcom er Inletl l

S 50.0 e 40.0

a. 30.0 20.0 10.0 0.07.2-18:5NAPSUnit Figure 25.0 50.0 75.0 100.0 125.0 10Co ntainme 150.0 175.0 200.0 (s)

Figure 7.2-18: NAPS Unit 1 Containmenft and Loop Pressures for the Limiting Break 7.2-30

Non-Proprietary 7.4 LOCA Summary 10CFR50.46 specifies that the ECCS for a commercial nuclear power plant must meet five criteria. The calculations and evaluations documented in this chapter demonstrate that the two NAPS units meet the required licensing criteria when operated with Advanced Mark-BW fuel.

LOCA calculations performed in concurrence with approved evaluation models (Reference 7-1 through 7-3) demonstrate compliance for breaks up to and including the double-ended severance of the largest primary coolant pipe. The co-residence of Advanced Mark-BW fuel and NAIF assemblies in the same fuel cycle is concluded to be of minimal consequence and does not cause the calculated clad temperature of either assembly to approach the limits of 10CFR50.46.

Specifically, this report, in conjunction with Dominion's LOCA evaluations for NAIF, concludes that when the North Anna units are operated with Advanced Mark-BW fuel:

1. The calculated PCT for the limiting PCT case is less than 2.200 F.

2. The maximum calculated local clad oxidation is less than 17 percent.

3. The maximum amount of core-wide oxidation does not exceed 1 percent of the fuel cladding.

4. The cladding remains amenable to cooling.

5. Long-term cooling is established and maintained after the LOCA.

Large break studies were performed for both units using the FANP RLBLOCA evaluation model (References 7-1 and 7-2). Tables 7.2-6 through 7.2-11 show the RLBLOCA results. The RLBLOCA analyses applied no Kz restraint on axial peaking, that is, Kz is set equal to one for all core elevations. The results of demonstrate LBLOCA compliance with the five criteria of 10CFR50.46. The mixed core was evaluated and no significant impact on either NAIF or Advanced Mark-BW fuel was identified.

Small break LOCA analyses were also performed for both NAPS units using the FANP deterministic EM (Reference 7-3, Volume II). Compliance with the five criteria of 10CFR50.46 was again demonstrated. The mixed core was evaluated with no significant impact on either fuel assembly design. SBLOCA analysis results are presented in Tables 7.3-8 through 7.3-19. The local power is axially restricted by the Kz curve in Figure 7.3-3.

Both large and small break LOCA analyses conclude that current NAPS UFSAR analyses remain valid for application to NAIF.

7.4-1