RS-17-082, Dresden Nuclear Power Station, Units 1, 2 & 3, Revision 12 to Updated Final Safety Analysis Report, Chapter 10, Steam and Power Conversion System
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DRESDEN - UFSAR Rev. 8 June 2009 10.0 STEAM AND POWER CONVERSION SYSTEM TABLE OF CONTENTS Page 10-i 10.0 STEAM AND POWER CONVERSION SYSTEM 10.1-1 10.1
SUMMARY
DESCRIPTION 10.1-1 10.2 TURBINE-GENERATOR 10.2-1 10.2.1 Design Bases 10.2-1 10.2.2 Description 10.2-1 10.2.3 Turbine Disk Integrity 10.2-4 10.2.3.1 Design and Materials 10.2-4 10.2.3.2 Inservice Inspection and Testing 10.2-5 10.2.4 Evaluation 10.2-5 10.2.5 References 10.2-6 10.3 MAIN STEAM SYSTEM 10.3-1 10.3.1 Design Bases 10.3-1 10.3.2 Description 10.3-1 10.3.3 Evaluation 10.3-2 10.3.4 Inspection and Testing Requirements 10.3-2 10.3.5 Water Chemistry Pressurized Water Reactor (PWR) 10.3-2 10.3.6 Steam and Feedwater System Materials 10.3-3 10.3.6.1 Fracture Toughness 10.3-3 10.3.6.2 Materials Selection and Fabrication 10.3-3 10.4 OTHER FEATURES OF ST EAM AND POWER CONVERSION SYSTEM 10.4-1 10.4.1 Main Condenser 10.4-1 10.4.1.1 Design Basis 10.4-1 10.4.1.2 System Description 10.4-1 10.4.1.3 Safety Evaluation 10.4-2 10.4.1.4 Tests and Inspections 10.4-3 10.4.1.5 Instrumentation Applications 10.4-3 10.4.2 Main Condenser Evacuation System 10.4-3 10.4.2.1 Design Bases 10.4-3 10.4.2.2 System Description 10.4-4 10.4.2.3 Safety Evaluation 10.4-4 10.4.2.4 Tests and Inspections 10.4-4 10.4.2.5 Instrumentation Applications 10.4-5 10.4.3 Turbine Gland Sealing System 10.4-5 10.4.3.1 Design Bases 10.4-5 10.4.3.2 System Description 10.4-5 10.4.3.3 Safety Evaluation 10.4-6 10.4.3.4 Tests and Inspections 10.4-6 10.4.3.5 Instrumentation Applications 10.4-6 10.4.4 Turbine Bypass System 10.4-7 10.4.4.1 Design Basis 10.4-7 10.4.4.2 System Description 10.4-7 10.4.4.3 Safety Evaluation 10.4-8
DRESDEN - UFSAR 10.0 STEAM AND POWER CONVERSION SYSTEM TABLE OF CONTENTS Page 10-ii 10.4.4.4 Tests and Inspections 10.4-8 10.4.4.5 Instrumentation Applications 10.4-8 10.4.5 Circulating Water System 10.4-8 10.4.5.1 Design Bases 10.4-9 10.4.5.2 System Description 10.4-9 10.4.5.3 Safety Evaluation 10.4-10 10.4.5.4 Tests and Inspections 10.4-10 10.4.5.5 Instrumentation Applications 10.4-10 10.4.6 Condensate Demineralizer System 10.4-10 10.4.6.1 Design Bases 10.4-10 10.4.6.2 System Description 10.4-10 10.4.6.3 Safety Evaluation 10.4-12 10.4.6.4 Tests and Inspections 10.4-12 10.4.6.5 Instrumentation Applications 10.4-12 10.4.7 Condensate and Feedwater Systems 10.4-13 10.4.7.1 Design Basis 10.4-13 10.4.7.2 System Description 10.4-13 10.4.7.2.1 Feedwater Regulating Valves and Low-FlowFeedwater Regulating Valve 10.4-15 10.4.7.3 Safety Evaluation 10.4-17 10.4.7.4 Tests and Inspections 10.4-17 10.4.7.5 Instrumentation Applications 10.4-18 10.4.8 References 10.4-19
DRESDEN - UFSAR Rev. 8 June 2009 10.0 STEAM AND POWER CONVERSION SYSTEM LIST OF TABLES Table 10-iii 10.1-1 Major Comp. Design and Performance Char acteristics of the Power Conversion System 10.3-1 Design, Fabrication, and Installation of the Main Steam Piping
10.4-1 Condenser Design and Performance Data
10.4-2 Deleted 10.4-3 Deleted 10.4-4 Feedwater Heater Characteristics 10.4-5 Feed Pump Characteristics DRESDEN - UFSAR Rev. 5 January 2003 10.0 STEAM AND POWER CONVERSION SYSTEM LIST OF FIGURES Figure 10-iv 10.2-1 Turbine Generation Set Flow Diagram and EHC Oil Supply 10.3-1 through 10.3-4 Deleted 10.4-1 Deleted 10.4-2 Deleted 10.4-3 through 10.4-13 Deleted
DRAWINGS CITED IN THIS CHAPTER*
- The listed drawings are included as "General Refere nces" only; i.e., refer to the drawings to obtain additional detail or to obtain background information. These drawings are not part of the UFSAR.
They are controlled by the Co ntrolled Documents Program.
DRAWING* SUBJECT M-12 Diagram of Main Steam Piping Unit 2 M-13 Diagram of Extraction Steam Piping Unit 2 M-14 Diagram of Reactor Feed Piping Unit 2 M-15 Diagram of Condensate Piping Unit 2 M-16 Diagram of Condensate Booster Piping Unit 2 M-17 Diagram of Condensate De mineralizer Piping Unit 2 M-18 Diagram of Heater Drain Piping Unit 2 M-19 Diagram of Heater Miscellaneou s Vent and Drain Piping Unit 2 M-36 Diagram of Circulating Water and Hypochlorite Piping M-43-1, -2, -3 Diagram of Off-Gas Piping Unit 2 M-345 Diagram of Main Steam Piping Unit 3 M-347 Diagram of Reactor Feed Piping Unit 3 M-371-1 Diagram of Off-Gas Piping Unit 3
DRESDEN - UFSAR Rev. 8 June 2009 10.3-1 10.3 MAIN STEAM SYSTEM The Unit 2 main steam system (MSS) is shown on Drawing M-12, and Unit 3 MSS is shown on Drawing M-345. The main steam isolation valves (MSIVs) are further discussed in Section 6.2. The safety relief valves (SRVs) are discussed in Section 5.2.
10.3.1 Design Bases
The performance objective of the main steam piping is to supply steam to the turbine-generator from the reactor vessel. To achieve this objective, the main steam piping was originally designed using the following bases:
Design pressure and temperature 1250 psig at 575
°F Piping design code USAS B-31.1
Since then the piping has been re-evaluated at uprated power conditions and found to be satisfactory.
10.3.2 Description The main steam piping consists of four lines which carry the reactor generated steam to the main turbine. Each steam line is equipped with two isolation valves, one on each side of the primary containment wall, and a combination flow restrictor and flow measuring venturi located between the reactor and the first isolation valve. The rated steam flow that the main steam line piping was originally designed to handle is 9.8 x 10 6 lb/hr at 965 psia. Unit operation would be permitted above rated steam flow rate and up to 9.90 x 10 6 lb/hr. Since then the piping has been re-evaluated at uprated power conditions and found to be satisfactory.
The MSS piping from the reactor vessel to the turbine is dynamically designed. The internal and external design load combinations and criteria are addressed in Chapter 3.
Design, fabrication, and installation of the main steam piping are summarized in Table 10.3-1.
In addition to providing steam to drive the main turbine, the MSS also provides steam to the following:
A. Turbine gl and seal system, B. Steam jet air-ejectors, C. Off-gas recombiner system, and D. Liquid radwaste reboiler.
Downstream of the outboard isolation valves, the four main steam lines are connected by a 30-inch diameter main steam equalizing header. Two 18-inch diameter lines connect the equalizing header to either end of the turbine bypass DRESDEN - UFSAR Rev. 5 January 2003 10.3-2 manifold. From the turbine bypass manifold, nine 8-inch lines connect to the turbine bypass valves, which discharge to the main condenser through horizontal perforated pipes located immediately below the tube bundles. The perforations are directed downward onto the condensate in the collecting trays. A maximum of 33.5% of rated steam flow can be bypassed to the main condenser.
From the main steam equalizing header, each of the four main steam lines passes through main steam stop valves and turbine control valves, then discharges to the high-pressure turbine.
Drains are provided at several locations along the main steam system to drain condensate from the line and return it to the condenser.
The main steam stop valves are described in Section 10.2. Steam pressure and flow measuring devices are described in Chapter 7.
10.3.3 Evaluation Leakage from the MSS into the steam tunnel is evaluated in Section 15.6.
Evaluations of the MSS response to seismic and pipe break events is contained in Chapter 3.
Dynamic loading of the main steam piping following turbine stop valve fast closure under extended power uprate conditions is discussed in Section 3.9.3.1.3.5.
10.3.4 Inspection and Testing Requirements
Inspection and testing for the main steam piping are essentially the same as those described in Section 5.2 for the primary process piping in general.
Portions of the main steam system within the primary containment are provided with removable thermal insulation to enable periodic inspection in accordance with the Technical Specifications.
Components and piping for the MSS were originally hydrostatically tested in accordance with ASA B-31.1. Inspection and acceptance standards were in accordance with ASME Code, Section VIII. All circumferential butt welds for 21/2-inch diameter piping and larger were specified to be 100% radiographed in compliance with paragraph UW51 of ASME Code, Section VIII.
Inservice inspection (ISI) of the MSS is outlined in Section 6.6. Testing of the main steam stop valves is addressed in Section 10.2. Testing of the MSIVs is addressed in Section 6.2.
The opening times of the main turbine bypass valves are measured after any maintenance is performed that may affect the operation of the bypass system but at least once per refuel outage prior to unit startup. The results are used to confirm that the appropriate bypass valve opening times were used to establish the OLMCPR, which is presented in the Core Operating Limits Report (COLR). 10.3.5 Water Chemistry Pressurized Water Reactor (PWR)
This section is not applicable to Dresden Station.
DRESDEN - UFSAR Rev 4 10.3-3 10.3.6 Steam and Feedwater System Materials The condensate/feedwater and main steam system piping, fittings, and valves connected to the reactor pressure vessel from and including the first weld at the vessel to and including the first isolation or shut off valve conform to ASME Section I. This piping is constructed of A 106 Grade B. The feedwater piping maximum wall thickness is 1.375 in. The main steam piping has a maximum wall thickness of 1.031 in.
The condensate and feedwater systems are described in Section 10.4.7.
10.3.6.1 Fracture Toughness
The 1965 edition of the code does not require impact testing nor does the original specification or ASTM specification. Current ASME Section III for class I components require impact testing. The Dresden Systematic Evaluation Program (SEP) compared the original testing requirements of the feedwater and main steam piping from the reactor vessel to the outermost isolation valve with the later code which requires impact testing if certain exemptions are not met. An exemption for a material is permitted if the lowest service temperature (LST) exceeds 150
°F. The LST is defined as the calculated minimum metal temperature whenever the pressure within the component exceeds 20% of the preoperational system hydrostatic test pressure. Due to the high service temperature, well above 150
°F, feedwater and main steam piping brittle fracture is not a problem and fracture toughness testing is not required.
10.3.6.2 Materials Selection and Fabrication
The materials selected for the main steam and feedwater piping, within the scope of the design specifications (including pipes, fittings, flanges, bolts, and valves), were originally in accordance with ASA B-31.1, which specified approved ASTM Specifications. The welding procedures are in accordance with ASME Code, Section IX. Austenitic stainless steel is not used in the main steam or feedwater piping.
DRESDEN - UFSAR Rev. 6 June 2005 (Sheet 1 of 1)
Table 10.3-1 DESIGN, FABRICATION, AND INSTALLATION OF THE MAIN STEAM PIPING Pipe Size 20 in. and 24 in.
Type Seamless ASTM Specification A 106 Grade B Schedule 80
Weld Joint Root pass Gas tungsten arc (TiG) Second pass Gas tungsten arc (TiG) Remainder Shielded metal arc (SMA)
Fittings Type Butt weld ASTM Specification B 16.9 ASTM Specification A 234 grade WPB Schedule 80 Notes 1. For piping 2" and under, ASTM A335 Grade P11 or P22 may be substituted for ASTM A106 Grade B material for the same schedule. For fittings and valves 2" and under, ASTM A182 Grade F11 or F22 may be substituted for ASTM A105 for the same rating. Substitutions are allowed up to a maximum temperature of 450
°F (operating or design) and apply to non-safety related piping and fittings only. No generic substitution of safety related piping/fittings is allowed.