ML20206S647

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Rev 0 to Procedure 28200-C, Turbine Overspeed Protection Reliability Program (Toprp). Analysis of Allowed Outage Times for MSIVs for Tech Specs Encl
ML20206S647
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Site: Vogtle Southern Nuclear icon.png
Issue date: 06/06/1986
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GEORGIA POWER CO.
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ML20206S627 List:
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28200-C, NUDOCS 8607070403
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A;py;ygg Procedur3 No.

Vogtb Electric Generating Plant A 28200-C

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h NUCLEAR OPERATIONS n g,,,, go.

0 ggg Unit COMMON Georgia Power e.ae no.

1 of 13 TURBINE OVERSPEED PROTECTION RELIABILITY PROGRAM (TOPRP) 1.0 PURPOSE This procedure establishes a comprehensive turbine maintenance program to ensure the integrity of the Turbine Rotor Assembly, operability of the Turbine Overspeed Protection System and overall reliability of the Main Turbine through periodic testing, calibration, maintenance and inspection. This program is performed in accordance with Technical Specification 4.3.4.2.

2.0 DEFINITIONS NUCLEAR PLANT RELIABILITY DATA SYSTEM (NPRDS) -

The NPRDS is a computerized data base, managed by INPO, used to track and trend nuclear power plant equipment reliability.

3.0 RESPONSIBILITIES 3.1 SAFETY REVIEW BOARD (SRB)

The Safety Review Board is responsible for the review of the safety evaluations for changes to this program in accordance with Technical Specifications Section 6.5.2.

3.2 GENERAL MANAGER The General Manager is responsible for the review, approval, and implementation of the TOPRP and changes thereto.

3.3 PLANT REVIEW BOARD The Plant Review Board is responsible for review of the I i

TOPRP and changes thereto in accordance with Technical 860707040 8606 0 PDR ADOCK 05000424 g

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INFORMATION - . . . .

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. PROCEDURE No. REVISloN PAGE No.

28200-C 0 2 of 13 3.4 MAINTENANCE SUPERINTENDENT The Maintenance Superintendent is responsible for:

3.4.1 Development of implementing Maintenance Procedures to meet the requirements of the TOPRP.

3.4.2 Ensuring testing, calibration, maintenance, and inspection requirements of maintenance procedures implementing the TOPRP are met or that deviations from requirements are reviewed and approved in accordance with this procedure, Plant Administration Procedures, and Technical Specifications.

3.4.3 Ensuring calibration, maintenance, and inspec' tion results are reviewed against acceptance criteria as specified in the implementing Maintenance Procedures and initiation of remedial or corrective action in accordance with Procedure 00150-C, " Deficiency Reports".

3.5 OPERATIONS SUPERINTENDENT The Operations Superintendent is responsible for:

3.5.1 Development of implementing Operations Procedures to meet the requirements of the TOPRP.

3.5.2 Ensuring testing requirements of the Operations Procedures implementing the TOPRP are met or that deviations from requirements are reviewed and approved in accordance with this procedure, Plant Administrative Procedures, and Technical Specifications.

3.5.3 Ensuring test results are reviewed against acceptance criteria as specified in the implementing operating procedures and the initiation of remedial or corrective action in accordance with Procedure 00150-C,

" Deficiency Reports".

3.6 SUPERINTENDENT, REGULATORY COMPLIANCE The Superintendent of Regulatory Compliance is responsible for the development and implementation of procedures to meet the NPRDS reporting requirements of TOPRP.

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, PROCEDURE No. REVISION PAGE No.

28200-C 0 3 of 13 4.0 TURBINE OVERSPEED PROTECTION RELIABILITY PROGRAM DESCRIPTION l 4.1 OBJECTIVE ,j The objective of the TOPRP is to improve turbine system ,

reliability by focusing on the prevention of l missile-generating turbine failures. The TOPRP consists of a comprehensive program for inspection of the Turbine Rotor Assembly, and testing, calibration, maintenance and inspection of the Turbine Overspeed Protection System. The program is designed to ensure that turbine disk flaws that might lead to brittle failure of the disk at speeds up to design speed will be detected. Material flaws or component failures in the overspeed sensing and tripping systems, main stop I valves, combined intercept valves, control valves, and extraction non-return valves that might lead to an overspeed condition above the design overspeed will be detected by this program, t 4.2 BASIS The TOPRP is based on calculations by General Electric for turbine missile generation probabilities, recommendations by General Electric Company for turbine

( inspection and turbine control and overspeed protection systems testing, calibration, maintenance and inspection, operating experience at nuclear plants with similar units, operating experience at other GPC plants, Final Safety Analysis Section 10.2 and regulatory guidance.

4.3 TESTING The testing program as presented in-Section 5.0 includes testing of the Turbine Overspeed Protection System, thrust bearing wear detector, and the main stop, control, combined intercept and extraction non-return valves. '

4.4 MAINTENANCE AND INSPECTION The maintenance and inspection program as presented in '

Section 6.0 includes aeriodic maintenance and inspection of the Turiine Rotor Assembly, main stop valves, control valves, combined intercept valves, and extraction non-return valves.

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,' PROCEDURE No. REVISICN PAGE No ,

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28200-C 0 4 of 13 i 4.5 CALIBRATION The Calibration Program as presented in Section 7.0 consists of calibration of the Turbine Overspeed Protection System and thrust bearing wear detector.

5.0 TRIP AND MONITORING UNIT TESTING REQUIREMENTS Each of the following tests shall be completed weekly (unless specified otherwise in this procedure) and prior to each startup (including after refueling outage) unless performed within the last 7 days.

NOTE 1 l

l Testing of the Trip and Monitoring Unit is not required to be completed when all the main steam isolation valves and associated bypass valves are in the closed position and all other steam flow -

paths to the turbine are isolated.

I 5.1 MECHANICAL OVERSPEED TRIP TEST During this test the Electrical Trip and Monitoring System energizes the Oil Trip Solenoid Valve which admits lubricating oil to the Overspeed Trip Device causing it to trip. A coordinated actuation of the Mechanical Lockout Solenoid Valve prevents the Emergency Trip System from actually tripping the turbine. This test should be completed just after the Backup Overspeed Trip Test.

5.2 MECHANICAL TRIP PISTON TEST During this test the Electrical Trip and Monitoring System energizes the Mechanical Trip Solenoid Valve, activating the Mechanical Trip Piston by shunting lube oil to the piston and tripping the Mechanical Trip System. A coordinated actuation of the Mechanical Lockout Solenoid Valve prevents the Emergency Trip System from actually tripping the turbine.

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PROCEDURE No. REUISloN PAGE No.

28200-C 0 5 of 13 5.3 ELECTRICAL TRIP TEST During this test the Electrical Trip and Monitoring System de-energizes both 24V DC Electrical Trip Solenoid Valves causing the Electrical Trip Valve System to trip. A coordinated actuation of the Electrical Lockout Solenoid Valve prevents the

! Emergency Trip System from actually tripping the turbine.

5.4 BACKUP OVERSPEED TRIP (BOST) TEST During this test each of the three BOST circuits are tested by simulating an overspeed condition. When the 4

test push button is depressed, the Auxiliary Speed Logic shunts a portion of the resistor-divider network,

, lowering the reference voltage to the BOST Test value.

Since the rated speed voltage exceeds the BOST Test

value, the differential Voltage Comparator energizes and activates the appropriate Trip Monitoring logic circuits. Becausc the three BOST circuits are connected in a two-out-of-three logic arrangement, the

?

In-Trip Monitoring circuits and each BOST circuit can ~

be tested individually without actually tripping the ,

turbine.

5.5 THRUST BEARING WEAR DETECTOR (TBWD) TEST Excessive wear on one of the thrust plates activates two pressure switches set at different levels of pressure, which correspond to different levels of

' displacements, the first representing an alarm level and the second a trip point. The pressure switch l

contatts are connected in series developing a
two-out-of-two logic for tripping. During this test, excess bearing wear is simulated in each direction by

! energizing the upper test solenoid valve and lower test

solenoid valve, respectively. The test solenoid valve I admits lube oil to the TBWD causing the probe to

! rise / fall. Accordingly, the probe piston will move

, down/up, shunting oil to the pressure switches'and causing the contacts of the pressure switches to close.

a The TBWD position meter in the control room will' follow i the movement of the piston and should be observed for  !

! full travel. The TBWD is temporarily disabled during 1 l the tests by opening a contact in the trip circuits the

! TBWD will not protect the turbine during testing.

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PROC'd DURE No REVISloN

' PAGE No.

28200-C 0 6 of 13 NOTE Testing of the TBWD should be done only during steady-state operations, particularly not during a period where feedwater heater valving is operated or any turbine valve tests are performed.

5.6 ACTUAL TURBINE TRIP TESTS

, Each of the following tests shall be performed at least once per 18 months or af ter major maintenance is performed on the turbine:

5.6.1 Mechanical / Electrical Trip Actuation During this test the turbine speed is allowed to increase to the trip setpoint of 110% of design speed causing mechanical and electric trip actuation and l.

X; actual tripping of the turbine.

5.6.2 Back-up Overspeed Trip Actuation

' During this test the BOST reference voltage is reduced to 105% of rated speed (simulating operation in the STANDBY MODE) and the turbine speed is allowed to increase to the BOST-STANDBY MODE trip setpoint of 105%

of design speed causing two-out-of-three logic to actually trip the turbine.

5.7 TESTING OF VALVES IMPORTANT TO OVERSPEED PROTECTION 5.7.1 All main stop, control and combined intercept valves will be tested with the turbine on line. Push buttons on the EHC Test Panel will be used to stroke main stop, control, and combined intercept valves from full-open to full-closed.

5.7.2 Turbine valve testing will be performed at the following intervals:

a. Main Stop Valves Weekly
b. Combined Intercept Valves Weekly
c. Control Valves Monthly 5.7.3 Closure of each valve will be verified by direct observation of valve motion at least once per month.

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. I PROCEDURE NO. REVISION PAGE No.

28200-C 0 7 of 13 l

5.7.4 All extraction non-return valves will be tested prior j to each startup.

5.7.5 Extraction non-return valves are tested locally by stroking the valve full open with air, then equalizing air pressure, allowing the spring closure mechanism to ,

close the valve. Closure of each valve is verified by l direct observation of the valve arm movement. '

6.0 MAINTENANCE AND INSPECTION REQUIREMENTS l

The inspection of valves important to overspeed protection and turbine rotor assembly includes the following:

6.1 MAIN STOP AND CONTROL VALVE TIGHTNESS TEST Tightness test of the main stop and control valves is performed at least once per 18 months by checking the coastdown characteristics of the turbine from no load with each set of four valves closed alternately. This test can reveal problems related to the internal ~

condition and to the operation of the valve.

6.2 MAIN STOP, CONTROL, AND COMBINED INTERCEPT VALVES

, CHECK At least one main stop, one control and one combined intercept valve are disassembled and inspected at an i approximate 3-year interval during refueling or maintenance outage. The inspection consists of:

a. Visual and surface examination of valve seats, disks, and stems,
b. Inspection of bushings, bore and stem diameters for proper clearance.

6.3 EXTRACTION NON-RETURN VALVES CHECK All extraction non-return valves are disassembled and inspected at an approximate 3-year interval during refueling or maintenance outage. This inspection consists of:

a. Visual check for wear of linkages and stem l packings. '
b. Visual check for evidence of valve seat, disk, and stem erosion.

( c. Free movement of the disk and proper adjustment of the balance weight will be verified.

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, PROCEDURE NO. REVISloN PAGE No.

28200-c 0 8 of 13 6.4 TURBINE ROTOR ASSEMBLY INSPECTION The Inspection Program for the Turbine Rotor Assemblies "

is done in sections during refueling or maintenance outages so that in 10 years, a total inspection has been completed at least once. This Inspection Program includes:

6.4.1 Last Stage Exhaust Region Inspection The inspection of the Last Stage Exhaust Region is made through the access manholes. No disassembly of the 4

turbine is required. This inspection can reveal a number of operational problems, last stage difficulties, and problems related to the internal condition in the turbine upstream of the last stage.

This inspection consists of a thorough visual inspection of parts visible from inside the exhaust hood plus red-dye examination of the last stage erosion shields. Specific areas inspected are:

a. Erosion shields are visually inspected for evidence of erosion. Both a visual inspection and -

surface (red-dye) examination for evidence of cracking (particularly stress corrosion cracking) is also performed.

b. Bucket vanes are visually inspected for evidence
of cracking, pitting, as well as trailing edge
erosion.

]

c. Peened covers are visually inspected for 1

indication of lifting and erosion of the covers cr tenons.

d. The accessible dovetail areas are visually inspected for signs of distress, pitting of the wheel or dovetail pins and loose dovetail pins,
e. The radial spill strips are visually inspected for evidence of rubbing.

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f. All accessible rotating and stationary parts are visually inspected for evidence of mechanical (impact) damage, as well as the build-up of deposits.

The inspection of the Last Stage Exhaust Region is performed at an interval of approximately 18-months during scheduled refueling or maintenance outages.

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,' PloCEDURE NO. REVISloN PAGE No.

28200-C 0 9 of 13 0

6.4.2 Low Pressure (LP) Rotor Assembly Inspection Disassembly of the LP sections is required to perform

! inspection of the respective LP rotor. Inspection of the LP rotors consists of:

a. Visual and surface examination of all external surfaces, including shaft, wheels, buckets, packing, and journals.
b. Surface (red-dye) examination of last stage erosion shields.
c. Volumetric (ultrasonic) examination of all finger dovetail pins, tangential entry dovetails and periphery of wheels.
d. Volumetric (ultrasonic) examination of inaccessible wheel bore and keyway surfaces, and the material in the vicinity of the bore.

Inspection of the LP rotors is performed at approximate 6-year intervals during refueling or maintenance -

outage.

6.4.3 High Pressure Rotor Assembly Inspection Disassembly of the 3P section is required to perform the inspection of the HP rotor. Inspection of the HP rotor consists of:

a. Visual and surface examination of all external surfaces, including rotor, buckets, packing, and j ournals . These examinations are performed at approximately 6-year intervals during refueling or maintenance outage.
b. Visual, surface (magnetic particle), and ultrasonic examination of the rotor from the ,

periphery and the bore of the rotor. These examinations are performed at approximately 10-year intervals during refueling or maintenance outage,

c. Volumetric (ultrasonic) examination of wheel

-dovetails on each stage. These examinations are performed at approximately 12-year intervals during refueling or maintenance outage.

6.4.4 Coupling and Coupling Bolt Inspection A visual and surface examination of all couplings and coupling bolts is performed at an approximate interval of 6 years during refueling or maintenance outage, mm i

PROCEDURE NO. REVISloN PAGE No.

28200-C 0 10 of 13 7.0 CALIBRATION REQUIREMENTS The Calibration Program for the Turbine Overspeed Protection System shall include the following at least once per 18 months or following major maintenance on the Turbine Generator or the Turbine Overspeed Protection System:

7.1 MECHANICAL OVERSPEED TRIP CALIBRATION i

The actual Mechanical / Electrical Overspeed Trip Test (Subsection 5.6.1) is designed to verify calibration of the Turbine Mechanical and Electrical Overspeed Trip System. The turbine speed is increased to the trip setpoint, and the speed at which the trip occurs is recorded. If the as-found trip value is out of tolerance, the trip setpoint is adjusted and the test is repeated.

7.2 BACKUP OVERSPEED TRIP CALIBRATION The actual BOST Trip Test (Subsection 5.6.2) is designed to verify the calibration of the electrical -

Auxiliary Speed Sensor Unit. In the NORMAL mode this trip is set at 110% of design speed and acts as a backup to the mechanical overspeed trip. In the

( STANDBY mode this trip is reduced to 105%'of design 4

speed and.provides the first line of protection. The actual speed at which the trip occurs is compared to the trip setpoint. If the as-found trip value is out of tolerance, the trip setpoint is adjusted and the test is repeated.

7.3 THRUST BEARING WEAR DETECTOR CALIBRATION The TEWD Test (Subsection 5.6.3) is designed to verify i 1

the operability and calibration of the TBWD pressure switches. If the as-found alarm or trip values are out ,

of tolerance, the pressure switches are adjusted and the test repeated. i 1

. 8.0 IMPLEMENTATION 8.1 This program is implemented by the use of approved procedures, maintenance work orders, and outage work schedules as'appropria*c.

8.2 Implementing procedures shall be written, reviewed, approved in accordance with Procedure 00051-C,

" Procedure Review And A

" Procedure Development"pproval" and Procedure 00050-C, t

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PROCEDURE No. REVISloN PAGE No. I 28200-C 0 11 of 13 t

9.0 PROGRAM CONTROLS 9.1 The Turbine Overspeed Protection Reliability Program

'shall be reviewed and approval recommended by the Plant Review Board (PRB) and approved by the General Manager prior to implementation.

9.2 Variation from the frequency requirements of the Turbine Overspeed Protection Reliability Program requires:

9.2.1 No test frequency shall exceed 1.25 times the required test interval without an engineering evaluation erformed in accordance with Procedure 00056-C, i p' Safety Evaluations" and without prior review of the PRB and approval of the General Manager.

9.2.2 Any deferral of test or inspections described in this procedure shall be in accordance with section 4.0.2 of '

Technical Specifications.

9.3 REVISIONS TO THE PROGRAM 9.3.1 The TOPRP is subject to on-going review and evaluation by GPC and is subject to revision based on operating data from this and other similar units or changes in General Electric Company's recommendations.

9.3.2 Changes to the TOPRP shall be reviewed and recommended for approval by:

a. Responsible Department Head,
b. Plant Review Board.

9.3.3 Changes to the TOPRP shall be approved by the General Manager.

9.3.4 The safety evaluation for changes to the TOPRP shall be reviewed by the Safety Review Board.

9.3.5 Implementation of changes will be accomplished in accordance with the provisions of 10CFR 50.59.

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g PROCEDURE No. REVISloN PAGE No 28200-C 0 12 of 13 10.0 REPORTING

'The main stop, control, combined intercept and extraction non-return valves shall be included in the Nuclear Plant Reliability Data System (NPRDS).

Deficiencies shall be reported and included in the data i bank, and reviewed so that appropriate changes may be made in the Vogtle Electric Generating Plant Program l based on reliability information.

11.0 RECORDS Records for the Turbine Overspeed Protection Reliability Program will be maintained in accordance  !

with the implementing procedures.

12.0 REFERENCES

12.1 TECHNICAL SPECIFICATION 12.1.1 3/4.3.4 " Turbine Overspeed Protection: )

12.1.2 6.5 " Review and Audit" -

12.2 FSAR Chapter 10.2 12.3 MANUALS 12.3.1 1X4AA01-280 " General Electric Instruction Manual GEK-64933 Vol. 1" 12.3.2 1X4AA01-281 " General Electric Instruction Manual GEK-64933 Vol. III" 12.4 PROCEDURES 12.4.1 00050-C, " Procedure Development" 12.4.2 00051-C, " Procedure Review and Approval" 12.4.3 00056-C, " Safety Evaluations" 12.4.4 00150-C, " Deficiency Reports" 12.4.5 14220-1, " Main Turbine Valves Weekly Stroke Test" 12.4.6 14286-1, " Weekly Turbine Trip Device Operability Test" FC344$

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PROCEDURE NO. REVISloN PAGE No

- 28200-C 0 13 of 13 12.4.7 14290-1, " Extraction Steam Non-Return Valves Weekly Test" 12.4.8 14540-1, " Main Turbine Valves Monthly Stroke Test" .

12.4.9 14785-1 " Annual Turbine Overspeed Trip Device Operability Test" 12.4.10 14989-C " Main Turbine EHC System Operability Test" 12.4.11 28205-C, " Main Turbine Valve Inspection" 12.4.12 27568-C " Main Turbine Disassembly, Inspection and Reassembly" 12.5 Title 10CFR 50.59 " Changes, Tests, and Experiments" 12.6 G.E. Technical Information Letter No. 969 (TIL - 969),

Periodic Turbine Steam Valve Test - Nuclear Units, May 22, 1984.

END OF PROCEDURE TEXT .

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1 Analysis of Allowed Outage Times for the Main Steam ..

Isolation Valves for the VEGP Unit 1 Technical Specifications l

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Purpose:

The purpose of the analysis is to estimate the frequency of core damage as a function of MSIV inoperability times for Vogtle and to compare this frequency to one calculated for Plant A which only has half the number of MSIVs as Vogtle.

II. Scope:

Four initiating events which could lead to core damage if the main steam lines are not isolated were considered. Independent and common cause failures of the MSIVs were considered.

III. Summary of Results:

The following core melt frequencies were calculated for Vogtle and Plant A for the MSIV inoperability times specified for the two dominant initiating event scenarios:

Plant A Vogtle MSIV MSLB Outside SG Tube MSIV Inoperability Containment Rupture Inoperability MSLBo SGTR No inop. MSIVs 1.325E-6 1.00E-6 No inop. MSIVs 1.01E-6 7.92E-7 1 MSIV inop. 2.94E-5 3.55E-5 2 MSIVs in one 2.51E-6 4.00E-6 all year line inop. all year 1 MSIV inop. 1.34E-6 1.016E-6 2 MSIVs in one 1.011E-6 7.935E-7 4 hrs /yr line inop. 4 hrs /yr 1 MSIV inop. 1. 56 E-6 1.28E-6 2 MSIVs in one 1.022E-6 8.18E-7 72 hrs /yr line inop. 72 hrs /yr 1 MSIV inop. 1.58E-6 8. 09 E-7 all year 1 MSIV inop. 7 1.02E-6 7.923E-7 days /yr IV.

Conclusions:

The results show that Vogtle has a somewhat lower probability for corenelt with one MSIV inoperable for 7 days /yr or for two MSIVs in one steam line D inoperable for 72 hrs /yr than Plant A does for one MSIV inopc' .tle for 4 hrs /yr.

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V. Methodology and Assumptions:

The methodology used is based on the calculations and data used in Plant A's PRA. The methodology and assumptions used will be explained in detail in the Body of Calculations (section VII).

VI.

References:

A. Plant A's PRA.

B. Classification and Analysis of Reactor Operating Experience Involving Dependent Events, EPRI NP-3967, Interim Report, June 1985.

t VII. Body of Calculations:

Simplified diagrams of the main steam systems for Plant A and Vogtle are shown on pages 3 and 4 (from Reference A and Vogtle drawing 1X4DB159-2, rev.15, respectively) .

A. Plant A core damage for MSIV failures:

The following calculations were performed for Plant A based on data and calculations in Plant A PRA (Reference A).

Four initiating events which could lead to core damage if main steam is not isolated were considered. The frequencies of.three initiating events were taken from Plant A's PRA and are as follows:

Event Mean MSLB inside containment 4.65 E-4 MSLB outside containment 6.04 E-3 SG tube rupture 1. 38 E-2 The fourth initiator is a combination-of initiators which require a turbine trip and then the- turbine trip function f ails. . 1he main initiator is a reactor trip which would probably lead to' a turbine trip at 100% power. The mean ' frequency of a reactor trip is 3.13 per reactor year. A conservative mean frequency of 10.0 will be used for the frequency that _ turbine trips are required. (Note that the " Turbine Trip" initiator is not related to this scenario. It is an initiating event which involves a successful turbine trip.)

2.

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PLANT A MAIN STEAM SYSTEM

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VOGTLE MAIN STEAM SYSTEM SL18 SLI-A TURBINE HEADER E/H MSA2 E/H MSA1 FC FC

( ( STEAM GENERATOR 1 FO SLI-B O SLI-8 LO MS8A1 MSBA2 SLl4 SLl-A E/H '"

MSB1 MSB2

( ( ( STEAM GENER ATOR 2 FO LO N SLI 8 SLl-A LO MS882 MS881 SL1-8 SLlA

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(( ( ( STEAM GENERATOR 3 FC FC FO SLl-8 LO SLI.A LO MSBC2 MSBC1 SLl-8 Sul-A ,

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1. MSLB inside containment (MSLB7 ):

For this initiator, in order to prevent two steam generators from blowing down, the affected steam line must be isolated or 3/3 of the other steam lines must be isolated. Failure is defined as failure of the affected SG and failure of one of the other 3 SGs (i.e., if steam line A breaks, then the cutsets are MSA MSB, MSA MSC, and MSA MSD where MSA, MSB, MSC, and MSD are the MSIVs for steam lines A, B, C, and D). The following tree represents the failures:

FAILURE TO 1 ISOLATE l 2 S.G.'s (GIVEN MSLBl) i m

I l FAILURE TO ISOLATE AF. BOTH TRAINS FECTED S.G. OF ISOLATION AND ONE OF THE LOGIC Fall OTHER THREE F3 O I I I I MSIV STEAM 1/3 OF OTHER TRAIN A TRAIN B LINE A FAILS S.G.'s Fall ISOLATION ISOLATION TO CLOSE TOISOLATE LOGIC FAILS LOGIC FAILS 8 A @ @

21190-6 I I MSIV STEAM MSIV STEAM MSIV STEAM LINE B FAILS LINE C FAILS LINE D FAILS TO CLOSE TO CLOSE TO CLOSE l

5 1

SLI-A and SLI-B are the ESFAS isolation trains A and B. If ESFAS fails, the operator can close the MSIVs f rom the control room, but no credit will be taken for operator action. Thus, the following is the equation for core damage f requency:

CDj = MSLBy [3Ams + (SLI-A)(SLI-B) + conunon cause]

a where MSLBI is the initiator frequency. The following failure data f rom Plant A's PRA was used:

Component Mean Failure Freauency Reference A,3 1.52E-3/ demand A (SLI-A)(SLI-B) for MSLB inside containment 1.14E-4 A MSLBI 4.65E-4 A To calculate common cause failure f requency, the " basic parameter method" as described in Section 4 of Reference B will be used. The following parameters will be used in this calculation:

Parameter Value Reference I

p(for MOVs) .0423 A y .5 John Stetkar (PLG) generic value 4 .9 John Stetkar (PLG) generic value c .99 John Stetkar (PLG) generic value Basically, what this table means is as follows:

Type of Failure Frequency Percentage of Ams independent (1-p)Ams .9577 12 consnon cause SAms .0423 exactly 2 consnon cause p(1-y)Ams .02115 exactly 3 common cause p(1-4)Ms .002115 exactly 4 conunon cause py4(1-c)Ams .00019 15 common cause py6c%s .01884 i

This shows that common cause failures in this analysis are predominantly either double failures or failures of five or more.

The common cause contribution is calculated as follows:

common cause = 3/36 (1-y)A + 3/3py(1-4)A + 1/.lpy4A

[The first term is for double failures. The denominator comes from the i number of doubles that involve MSA (i.e., MSA MSB, MSA MSC, and MSA

MSD.) The numerator is the number of doubles out of all doubles possible (2 = 6) AB, AC, AD, BC, BD, CD 6

_ . _ . - = _ - _ _ _ _ _ . _ ,__.,,,_,,_,____.,__,._-_,,.-_,_.y_. ,_,.,_._,_.c... _

m_ ,_ , , . . _ _ _ . _ __ _ . . - _ . . _ , . . - ,_

which constitute a failure (in this case only AB, AC, and AD, since it is assumed that the line break is in line A)].

f The second term is for triple failures. The denominator is the number of triples involving MSA (= 3 MSA MSB MSC, MSA MSB MSD, MSA MSC MSD) and the i numerator represents the ones out of the 4 possible combinations I3  ! " 4) that constitute a failure (the same three as the denominator) 1

, The last term is for quadruple failures. (There is only one quadruple i

possible and it is a failure.)

Therefore, the common cause term is equal to the following:

l common cause = 3/3(.0423)(.5)Ams + 3/3(.0423)(.5)(.1)Ams +

l 1/1(.0423)(.5)(.9)Ams

= ( .0212 + .0021 + .0191) Ams

= .0423 A ,, = SA,,

1 Thus, the following is the equation for core damage frequency:

CDj = MSLBy [3A,3 + (SLI-A)(SL1-B) + SA ms l

= (4.65E-4) [3(1.52E-3)2 + (1,14E-4) + ( .0423)(1.52E-3)]

j = (4.65E-4) [6.93E-6 + 1.14E-4 + 6.43E-5]

= (4.65E-4)(1.85E-4) = 8. 61 E-8

2. MSLB outside containment (MSLBo):

For this initiator, in order to prevent two SGs f rom blowing down, 3 out of 4 steam lines must isolate, since all steam lines are connected to a common header. Failure is defined as any combination of 2 out of 4 MSIVs i failing to isolate (i.e., MSIVs fail for the following combinations of l steam lines: AB, AC, AD, BC, BD, CD). The following tree represents the '

failures (again assuming no operator action):

1 T 1

FAILURE TO ISOLATE 2 S.G.'s (GIVEN MSLBol b

I I FAILURE TO BOTH TRAINS ISOLATE OF ISOLATION 2/4 S.G.'s LOGIC FAIL r3 r3 j 2/4 I I I I I I MSIV STE AM MSIV STE AM MSIV STEAM MSIV STEAM TRAIN A TRAIN B LINE A FAILS LINE B FAILS LINE C FAILS LINE D FAILS ISOLATION ISOLATION TO CLOSE TO CLOSE TO CLOSE TO CLOSE LOGIC FAILS LOGIC FAILS 8 8 8 8 @ @ ,

l Thus, the following is the equation for core damage frequency

  • CD2 " MbL0o E0Ams + (SLI-A)(SLI-B) + connon cause)

The connon cause in this case is given by the following:

common cause = 6/3 p(1 7) Ams + 4/3 sy(1 -4) Ams + 1/1 SY6Ams

- (.0423 + .00282 + .0190)Ams -

= .06412 Ams The following Plant A PRA data is used:

Component Mean Failure Freauency Reference Ams 1.52E-3/ demand A (SLI-A)(SLI-B) 1.08E-4 A for MSLB outside containment 1 MSLB G 6.04E-3 A 8

Thus, CD2 = (6.04E-3) [6(1.52E-3)2 + 1.08E-4 + (.06412)(1.52E-3)]

=

(6.04E-3) [1.39E-5 + 1.08E-4 + 9.75E-5]

=

(6.04E-3) (2.194E-4) = 1.325E-6

3. Steam Generator Tube Rupture (SGTR):

For this initiator, to be successful the affected SG aust be isolated or all three steam dump valves (SDVs) and all three of the other MSIVs must j be closed. There is no ESFAS isolation signal so the operator must perform the isolation. Operator error dominates the frequency of this core damage scenario. Failure is defined as failure to isolate the

, affected SG and failure to isolate 1/3 SDVs or 1/3 of the other MSIVs.

1 J

i T

(

4 t

1 9

i

FAILURE TO ISOLATE FOR SGTR IN S.G. "A" n i I I 1/3 SDV's FAIL I

T LOSE MSI FAI TO SGTR CLOSE em I I 1/3 SDV's .

1/3 OTHER F AIL TO CLOSE F AIL T CLOSE A A

  1. % 1em ,

I I I I SDVc (A) SOVc (B) SDV C) MSIV STEAM MSIV STEAM MSIV STEAM FAILS TO CLOSE F AILS TO CLOSE FAILS Tb(CLOSE LINE B F ILS LINE C F ILS LIN F ILS T

O SOVe(A)

O SOVc(B)

O SOVc(C) 8 8 8 The common cause failure is the same as case 1 so the frequency is given by phis. Thus, the following is the equation for core damage frequency:

CD 3 a N ware) = SGH D ,3(3ASDVc + ms

  • O ms The following Plant A PRA data was used:

Component Mean Failure Freauency Reference Ams 1.52E-3/ demand A Smov 4.23E-2 A ASDVc 2.66E-4/ demand A SGTR 1.38E-2 A 10

l 4

Thus, CD 3 (hardware) = (1.38E-2)[(1.52E-3) {3(2.66E-4) + 3(1.52E-3)}.

+ ( .0423)(1.52E-3)]

i = (1.38E-2)[(1.52E-3) {8E-4 + 4.56E-3} + 6.43E-5)  ;

= (1.38E-2)(7.24E-5)  ;

i

= 1.00E-6 Human failure is much larger than this frequency.

4. Turbine Trip Failure (TT):

l The initiating event requires a turbine trip. Failure of turbine trip  !

consists of failure of the turbine trip control or failure of 1/4 turbine ,

i stop valves (TSVs) and 1/4 turbine control valves (TCVs). Failure of the 1 turbine trip control consists of the failure of the electrical trip l solenoid valve to operate on demand (deenergize to dump) or failure of the electrical trip valve to operate on demand (depressurize to dump) and  !

J 4

the failure of the mechanical trip pilot valve to operate on demand (trip l to dump). Thus, the turbine trip failure is given by the following i equation: 3 J

4 4 I' TT = IE TSV {I TCVk }]

TT[Tcontrol +j,I) j k=1 I

Tcontrol = [ETSV + ETV] [MTPV) where IETT is the initiating event requiring a turbine trip.

If turbine trip fails, 3/4 steam lines need to be isolated as in case 2  :

} (MSLB o ). Therefore, core damage is given by:  !

i.  :

j CD4 - TT [6%s2 + (SLI-A)(SLI-B) + (.06412) %3] [

i The following Plant A PRA data was used:

[

j Basic Event Mean Failure Frecuency Reference l l

Ms, MTPV 1.52E-3/ demand A f

Smov 4.23E-2 A (SLI-A)(SLI-B) j for a transient 6.30E-5 A i

TSV, TCV 1.25E-4 A i ETSV 2.43E-3 A l

! ETV 2.66E-4 A l

l IETT 10.0 estimate based i j on Reference A  :

I 1

11
t i

! t i

Thus, CD = 10[{2.43E-3 + 2.66E-4)(1.52E-3) + 16(1.25E-4) }

4 X{6(1.52E-3)2 + 6.30E-5 + ( .06412)(1.52E-3)))

= 10[{4.10E-6 + 2.50E-7} {1.743E-4}]

= 7.58E-9 B. Conclusions from Plant A PRA:

The dominant failure frequency for core damage comes f rom human error for a SGTR. The dominant hardware failures are from SGTR and MSLBo.

C. Core Damage Frequency for Vogtle for Main Steam Isolation Failures:

Since MSLBo and SGTR dominate the hardware failure modes, only these two scenarios will be analyzed for Vogtle.

1. MSLBo The tree on the following pages represents the failures for Vogtle:

1 12

. . - . _ ... - . - . - .-_ .._ - .. _ ~. - _ . -

3 i

4

- F AILURE TO ISOLATE 2 5.G.'s (GIVEN MSLBo) l I I I SLI.A FAILS SLl-B FAILS AND 2/4 AND 2/4 SOTH TRAINS 2/4 STEAM

} TRAIN 8 TRAIN A OF ISOLATION LINE I.V/s

, STEAM LINE STEAM LINE LOGIC Fall FAIL 1.V.'s 1.V/s o o n n8 j.

]A 5

" I I I l

TRAIN A 2/4 TR AIN 8 TRAIN 8 2/4 TRAIN A ISOLATION STEAM LINE ISOLATION STEAM LINE LOGIC FAILS 1.V/s Fall LOGIC F AILS 8.V/s FAIL t O O A 2/4 8 2/4 I I I 1 I I I I I I i 1

STEAM LINE A STEAM LINE 8 STEAM LINE C STEAM LINE D STEAM LINE A STEAM LINE 8 STEAM LINE C STEAM LINE D TRAIN 8 TRAIN 8 TRAIN 8 TRAIN 8 TRAIN A TRAIN A TRAIN A TRAIN A 1.V/s F All I.V/s Fall I.V.'s FAIL l.V/s Fall 1.V/s F AIL 1.V/s FAIL l.V/s Fall 1.V/s FAIL j

s$IM j

4 i

a

I STEAM LINE A STEAM LINE A (B,C,D) TR AIN B (B,C,D) TR AIN A AB\ 1.V.'s Fall A\ 1.V/s Fall BB BA DA em em I I I I

STEAM LINE A STEAM LINE A STEAM LINE A STEAM LINE A (B,C,D) (B,C,D) TR AIN B (B,C,D) TRAIN A (D.C D) TRAIN A MSBlV FAILS MSIV FAILS MSBlV FAILS MSIV ILS O

MSA2 O

MSBA2 O

MSA1 O

MSBA1 MSB2 MSBB2 MSB1 MSBB1 MSC2 MSBC2 MSC1 MSBC1 MSD2 MSBD2 MSD1 MSBD1 BOTH TRAINS b ISOLATION

/A\ LOGIC FAILS f3 I I TRAIN A TRAIN B ISOLATION ISOLATION LOGIC FAILS LOGIC FAILS O

SLlA O

SLI.B l

f i

14

D E L .

N8I INA 8

l LIF mas AR/

E T

TV. 1 A

DD S EN NA I

I LA I MS*

AN

  • EIA D

SR' T

T E L NAIA g D L

I IN LIF mas AR ET1 T

/

V.

A S S C

E l

- N8l INA 8

I LIF mas AR/

E T

TV.

1 A

CD S EN N

IA' I

LA I MS' AN EIA T

S R' T

C E l NAlA g

C L

I IN LIF mas AR /

ETV. I A

S T S

Ms/

AV l E 4 TIl /

SEA 2 4NF

/I 2L 8

E l N8l INA LIF A

I

\ mas AR/

8 8 E TV.

1 8 D T S

NA I ENN ILA I mss ANW E

I AI T 8 SRT E l NAlA IN A

I LIF

\ M A's.

, AR L ETV. 1 3 T S _

A _

E L _

N8I _

INA _

8 I LIF mas AR'.

ETV.

T I

A .

AD S ENL NAAI I

I LAF l mss AN

/

EIV.

T A1 SRT A E l NAlA I ILN mas AR IF ETV.

T f

8 A

n S au

1 l

The following equation for core damage including common cause failures for Vogtle is as follows:

CD2 = MSLB, USLIA+SLIB) (6Ams + 6A + 12 1,3 Amsb msb

+ f S(1-Y) Ams + hY(1-4)Ams+hSy4(1-c)Ams 6 28 47

+ y S(1-Y)Amsb + { SY(I-8)Amsb + y SY 8(I-8)Amsb)

+ (SLIA)(SLIB) + {6 Ams + 24 Ams Amsb + 36 Ams hsb 6

+ 24 Ams Amsb 3 + 6 Nsb4} + ~ SY (I-c)Ams A 6

+ g SYo(1-c)Amsb + SY cams 4 + SY4ckmsb + SAmsSAmsb]

To explain the terms in the equation above, MSIVs and MSBIVs will be

, represented as follows:

1 A B X X 1gg2 LINE A 1,3,5,7, A,C, E & G ARE ACTUATED BY SLIA

C D 3 4 LINE B 2,4,6,8, B, D, F & H ARE ACTUATED BY SLIB E F 5 6 LINE C 1

G H m -

7 8 LINE D The first 9 terms involve failure of either SLIA or SLIB and failure to i

isolate either the MSIV or MSBIV in two out of the four steam lines.

a. If SLIB fails, then the first term represents failure of 2/4 of the MSIV's 1, 3, 5, or 7. There are six combinations of independent l failures l

l 4! 4,3 (2'2' " 2 = 6) f 1,3 1,5 1,7 3,5 3,7 5,7 (Thus the term 6%52,)

  • 4 b. If SLIB fails, then the second term represents failure of 2/4 of the MSBIV's A, C, E, or G. Six combinations A,C A,E AG C,E C.G E,G (Thus the term 6Amsb2 ,)

i 16 ,

c. If SLIB fails, then the third term represents the failure of one MSIV and one MSBIV. The following combinations result in failures:

1,C 3,A 5,A 7,A 1.E 3,E 5,C 7,C 1,G 3,G 5,G 7,E (Thus the term 12 M s M sb)

d. The fourth term involves a dependent failure of 2 MSIVs out of 4.

The denominator represents the number of doubles that valve no. 1 can be involved in: 1,2 1,3 1,4 1,5 1,6 1,7 1,8 (1 x 7 = 7).

The numerator represents the number of double failures that would constitute a system failure. All the possible double failures (2

=

= 28) are as follows:

4 12 23 (35) X 48 (13) X 24 36 56 14 25 (37) (57)

(15) X 26 38 58 16 27 45 67 (17) X 28 X 46 X 68 18 34 47 78 ,

If SLIA fails, the 6 double failures with an "X" to the left will

! cause system failure. If SLIB fails, the 6 double failures in parentheses will cause system failure.

I

e. The fifth term involves a dependent failure of 3 MSIVs that would fail the system given SLIA or SLIB has failed.

The denominator is the number of triples that valve no.1 can be involved in:

= 21 1 x (2) " I

  • 2 The numerator is the number of triple failures that would constitute a system failure. The failures out of all possible combinations are indicated on page 18. The numerator for this term is 28.
f. The sixth term involves a dependent failure of 4 valves that would fail the system given SLIA or SLIB has failed.

The denominator is the number of quadruplets that valve no. I can be involved in:

1 x (3) " I

  • 3 x

= 35 l

17

i 1

I8h 81 887*8 I 8 at 887eS*5 j ja " " 56 I e = = 70 (3 j 31 El 3*281 I 4 41 41 483*2*1 I

1 I I

1 COMBINATIONS OF THREE I COMBINATIONS OF F0um I

i i '123' '178' '356' I (1234) #1357' '2357' (3478)

"124' "234" '357' I '1235' '1358' "'2358'" '3567*

! *125' '235' '358' I "'1238'" '1367' **2367'" "'3568'"

"126* "236* '367' I '1237' "'1388'" "2368" '3578'

  • 127' '237' "368" I "'1238'" '1378' "'2378'" "'36788" I
  • 128" "238" '378* I "*1245'" "'1456*" "2456" "*4567'"

'134' "245" "456* I *1246" '1457' "'2457'" "4568"

  1. 135' "246" '457' I "*1247'" "'14588" "2454" "'4578'"
  • 136' "247" "458" I "1248" "*1467'" "2467" "4678"
  • 137' "248" "467" I (1256) "1468" "2468" (5678)

I

  1. 138' "254" "468" I '1257' "'1478'" "2478"

+ '145' '257' "478* I "'1258'" '1567' "*2567'"

, "146" "258" '567' I **1267'" **1568'" "2568" j -a *147' "267" "568" I "1268" '1578* **2578'"

03 *148" "268" '578* I (1278) "'1878'" "2678" i

I

  • 156' "275" "67a* I '1345' "'2345'" (3456)
  1. 157' '345' I "'1346'" "2346" '3457'

'158' "346" I '1347' "*2347'" "'3458'"

r '167' '347' I "'1348'" "2348" "*3467'"

j *168" "348* I *1356' "'2356*" "3468"

' I j I SLI-A + " TRIPLES *

  • 28 I ( GUARANTEED FAILURE ) *6 SLI-5 + ' TRIPLES * = 28 I SLI-A + " QUADRUPLES " = 47 I SLI-B + ' QUADauPLES *
  • 47 i

.i i

(

'b l

The numerator is the number of quadruple failures due to common cause that would constitute a system failure. Those six that are marked 2

quaranteed failures are not counted because they fail the system whether SLIA or SLIB fails or not and are minimal cutsets by s

themselves. The numerator is therefore equal 47 as shown on page 18.

g. The next three terms (7-9) are similar to the terms 4-6 except the common cause failures involve the MSBIVs instead of the MSIVs.
j. h. The tenth term is the failure of both SLIA and SLIB.
i. Terms 11-15 are independent failures of various combinations of MSIVs and MSBIVs. All the possible combinations are shown on page 20.

1 a j. The 16th term represents the six guaranteed failures shown on page 18 j ,

for quadruple common cause failures of MSIVs.

, k. The 17th term represents the following six guaranteed failures left out of term no. 9 for quadruple common cause f ailures of MSBIVs:

ABCD, ABEF, ABGH, CDEF, CDGH, and EFGH.

~

1. The 18th and 19th terms are common cause failures of 5 or more MSIVs

, and 5 or more MSBIVs, respectively. All combinations of 5 or more are conservatively assumed to cause system failure.

] m. The last term represents a common cause failure of 2 or more MSIVs ,

, colticident with a common cause failure of 2 or more MSBIVs which is conservatively assumed to cause system failure.

l (Note: some terms are omitted in the equation for CD2 but later it i will be shown that they are negligible compared to the dominant terms above.)

The mean failure frequencies listed on pages 6 and 8, and the j following data will be used to quantify CD2 Component Mean Failure Frecuency Reference f Amsb 1.52E-3 A (air-operated
valves) 1 SLIA 9.95E-3 A SLIB 9.95E-3 A f

! 19 4

i i

4 4' Term no.11 4 MSIVs (6(4)=6(4gf3)=6 combinations) 1,2,3,4 1,2,7,8 3,4,7,8 1,2,5,6 3,4,5,6 5,6,7,8 Term no. 12 3 MSIVs and 1 PSBIV (6(3) = 6x4 - 24 combinations) 1,2,3,0 1,2,7,H 1 B,7,8 3,4,5,F 3,D,5,6 5,6,7,H 1,2,4,C 1,2,8,G 2.A,3,4 3,4,6,E 3,0.7,8 5,6,8,G 1,2,5,F 1.B,3,4 2,A,5,6 3,4,7,H 4,C,5,6 5,F,7,8 1,2,6,E 1.B,5,6 2,A,7,8 3,4,8,G 4,C,7,8 6,E.7,8 Term no.13 2 MSIVs and 2 MSBIVs (6(2) = 6x = 36 combinations) 1,2,C,0 1,B,3,0 2.A,3,0 3,D,5,F 4,C,7,H 3,4,A,B 1,2,E,F 1,B,4,C 2 A,4,C 3.0,6,E 4,C,8,G 5,6,A,8 1,2,G,H 1.B,5,F 2 A,5,F 3,D,7,H 5,F,7,H 5,6,C,0 3,4,E F 1.B,6,E 2.A,6,E 3,D,8,G 5,F,8,G 7,8,A,B 3,4,G,H 1.B,7,H 2 A,7,H 4,C,5,F 6,E,7,H 7,8,C,0 5,6,G H 1 B,8,G 2.A,8,G 4,C,6,E 6,E,8,G 7,8,E,F Term no.141 MSIV and 3 MSBIVs (6(2) = 6x4 = 24 cus.binations) 1,B.C,0 2.A.E F 3,D,G,H 5,F.A,B 6,E,C,0 7,H,E.F 1,B,E,F 2.A.G H 4,C.A,B 5,F.C,0 6,E G,H 8,G.A.B 1,B,G H 3,D.A,8 4,C,E,F 5,F,G,H 7,H,A,B 8,G,C,0 2.A.C,0 3,0,E,F 4,C,G,H 6,E.A,8 7,H,C,0 8,G,E F Term no.15 4 MSIVs (6(0) = 6x1 = 6 combinations)

A,B,C,D A,B,G,H C,0,G,H A,B,E,F C.D.E F E.F,G,H 20

--. --- _ - . - - - ---,-i

Thus, sor Vogtle CD2 is given by the following:

CD2 = (6.04E-3)[(9.95E-3 + 9.95E-3){6(1.52E-3)2 + 6(1.52E-3)2

+ 12(1.52E-3) + 2( )(.0423)(.5)(1.52E-3) + 2( )(.0423)(.5)(.1)(1.52E-3) 47

+2(33)( .0423)( .5)( .9)( .01)(1.52E-3} } + 1.08E-4 + 96(1.52E-3)4

+ 2( )(.0423)(.5)(.9)(.01)(1.52E-3) + 2(.0423)(.5)(.9)(.99)(1.52E-3)

+ (.0423)2 (1.52E-3)2]

CD2 = (6.04E-3)[(1.99E-2){1.386E-5 + 1.386E-5 + 2.772E-5

+ 5.51 E-5 + 8.57E-6 + 7.8E-7 } + 1.06E-4 + 5.12E-10

+ 9.9E-8 + 5.73E-5 + 4.13E-9]

CD2 = (6.04E-3)[(1.99E-2)(1.199E-4) + 1.08E-4 + 5.12E-10

+ 9.9E-8 + 5.73E-5 + 4.13E-9]

= 6.04E-3 (1.678E-4) = 1.01E-6 (Some tenns that were neglected are as follows:

1. Triple conunon cause failure of the MSIVs plus an independent failure (page 22).

This tenn would be:

24 2

{ Sy(1-6) gs2=({24 )(.0423)(.5)(.1)(1.52E-3) = 5.6 x 10-9 This is very negligible compared to 1.08E-4 for (SLIA)(SLIB).

Another term equal to this one would apply for the MSBIVs.

ii. Quadruple connon cause failures of the MSIVs plus an independent failure (page 22).

1 This term would be:

96 2 gSy4(1-r)Ms2 = (96g)(.0423)(.5)(.9)(.01)(1.52E-3) = 1.2E-9 which is negligible compared to 1.08E-4. (A similar term applies to the MSBIVs.)

l 21

i I 8\ =

81

=

8*7*6

= 56 I

l I 8)

  • 81

=

8*786*5

= 70 l I 31 El 3*2*1 I (4) 41 41 4*3*2*1

, (3) I I

I

- COMOINATIONS OF THREE I COMBINATIONS Dr FOUR I

123 (4) 178 (2) 356 (4) I (1234) 1357 2357 (3478) 124 (3) 234 (1) 357 I 1235*46" 1358 2358 3567"48" 125 (6) 235 358 I 1236"45" 1367 2367 3568"47=

126 (5) 236 367 I 1237"48" 1368 2368 3578"46" 127 (8) 237 368 I 1238"47" 1378"24" 2378"14" 3678"45" I

< 128 (7) 238 378 (4) I 1245"36" 1456"23" 2456"13" 4567"38" 134 (2) 245 456 (3) I 1246"35" 1457 2457 4568"37" 135 246 457 I 1247"38" 1458 2458 4578*36"

. 136 247 458 I 1248"37" 1467 2467 4678"35"

, 137 248 467 I (1256) 1468 2468 (5678) i i

! I d

138 256 (1) 468 I 1257"68" 1478"23" 2478"13" I 145 257 478 (3) I 1258"67" 1587"28" 2567"18" 3 -

na 146 258 567 (8) I 1267"58" 1568"27" 2568"17"

} ha 147 267 568 (7) I 1268"57" 1578"26" 2578"16" a 148 268 578 (6) I (1278) 1678"25" 2678"15" I

156 (2) 278 (1) 678 (5) I 1345"26" 2345'18" (3456) 157 345 (6) I 1346"25" 2346"15" 3457"68"

158 346 (5) I 1347"28" 2347"18" 3458"67" j 167 347 (8) I 1348"27" 2348"17" 3467"58" 168 348 (7) I 1356"24" 2356"14" 3468"57" I

i THE 16JISER OF THE VALVE THAT FAILS INDEPENDENTLY IS I EITHER OF THE TWO VALVES IN THE 006LE QUDTATION 4

IDWICATED IN PARENTHESES TO THE RIW1T OF THREE VALVES I MARKS FAILING INDEPENDENTLY WITH THE CopOION CAUSE i THAT FAIL DUE TO COMMON CAUSE FAILURE. I FAILURE OF THE FOUR VALVES TD THE LEFT WILL CAUSE I SYSTEN FAILURE.

TRIPLES + ( INDEPENDENT FAILURE ) = 24 I QUADRUPLES + " INDEPENDENT FAILURE " = 96

! I I THE QUADRUPLETS IN PARENTHESES ARE GUARANTEED '

l I FAILURES = 6 i

i .

)

l .

i

{

FAILURE TO ISOLATE GIVEN TUBE RUP10RE IN STEAM GENE R.

A~ DR A g n -

sa m c7 m V@ H r+ 3D c -%

I as F AILUR E.TO F All TO ISOLATE A a"

mk ISOL AT E STE AM DUMP

"[

4>

j O

O  ?$

m.

  • e

-- -m ,

>e av e

m

, e STEAM LINE A STEAM LINE A c+

TRAIN A TRAIN 8 m i V,*s Fall 1,V.'s F AIL

r N PAGE PAGE a 14 14 c i
2 m

FAllTO Fall TO ISOLATE ISOLATE A!3 1 OF 3 RFMAIN.

I ' STE AM DUMP ING STE AM LINES < i VALVES j O O h

-, -s  ;

I 4

e 5

s

. Fall TO Fall TO FAIL TO STEAM LINE 8 STEAM LINE C STEAM LINE D ISOLATE STEAM ISOLATE STEAM ISOLATE STEAM TRAINS A AND 8 TRAINS A AND 8 TRAINS A AND 8 r+

DUMP A DUMP 8 DUMPC l.V.'s Fall B.V/s Fall 1.V/s Fall [

O SDVe(A)

O SDVe(8)

O SOVe(C)

A PAGE A

PAGE A

PAGE l

15 15 15 J

l

The equation for core damage (neglecting multiple independent failures) is:

1 6 12 CD3 = SGTR[(3ASDVc hs2+i M Ns+ @ M Ms+ 9 M 'Ns 1 6

+Amsb2 + y p(1-y) Amsb+hDY(I-3)Msb 12 24 2

+ (g) Sy4(1-c))asb + 2Ams Amsb) + jJ SY(1-6) Ams 96 3

+ ] py&(1-c) Ams 2 + { Sy6(1-c) Ams 24

+ { SY(1-4)Amsb 2 + {96 py4(1-c)Amsb 2 3

+ g Sy&(1-c)Amsb

+ SY6 cams + DY6cAmsb + Elms BAmsbl The first nine terms involve a failure to isolate the affected S.G. plus a failure of one of the steam dump valves to isolate,

a. The first term represents MSAl and MSA2 failing independently.
b. The second term is for a double common cause failure of MSIVs (numerator = 1 since only combination 1,2 is a failure).
c. The third term is for all triple common cause failures on page 25 which contain MSIVs 1 and 2 (denominator = 1 x (2) " 21)*
d. The fourth term is for all quadruple common cause failures on page 25 which contain MSIVs 1 and 2 except for the 3 guaranteed failures (denominator = 1 x (3) = 35).
e. Terms 5-8 are similar to terms 1-4 except they involve the MSBIVs.
f. The ninth term represents the failures MSAl MSBA2 and MSA2 MSBAl with one of the three SDVs.

The remaining terms represent a failure to isolate the affected S.G. and to isolate one of the other 3 S.Gs.

g. The tenth term represents the 24 triple common cause failures of MSIVs plus an independent failure as indicated on page 25.
h. The lith term represents the 96 quadruple common cause failures of-MSIVs plus an independent failure (neglecting the 3 guaranteed failures) as indicated on page 25.
i. The 12th term represents the three guaranteed failures on page 25 for quadruple common cause failures of MSIVs.

24

i i

l I) 8

=

8t 8*7*6

" 56 I I 8) 8f Se7*6*5

" 70 I l" (3j 3l 51 3*2*1 (4j 41 41 4*3*2*1 l

I

, I CON 8INATIONS OF THREE I CON 8INATIONS OF FOUR I

I K 123 (4D) 178 (26) 356 I (1234) 1357 2357 3478 X 124 (3C) 234 (1 A) 357 I X 1235"460F" 1358 2358 3567

' X 125 (SF) 235 358 I X 1236*45DE" 1367 2367 3568 X 126 (SE) 236 367 I X 1237"480H" 1368 2368 3578

X 127 (8M) 237 368 I X 1238"47DG" 1378 "26" 2378 "1A" 3678 i I

! X 128 (7G) 238 378 I X 1245"36CF" 1456 "28" 2456 "1A" 4567 l 134 (28) 245 456 I X 1246"35CE" 1457 2457 4568 j 135 246 457 I X 1247"38CH" 1458 2458 4578 j 136 247 458 I X 1248"37CG" 1467 2467 4678 i 137 248 467 I (1256) 1468 2468 5678 I

i' 138 256 (1A) 468 I X 1257"68FH" 1478 "28" 2478 "1A" 145 257 478 I X 1258"67FG" 1567 "28" 2567 "1A" l @ 146 258 567 I X 1267"58EH" 1568 "28" 2568 "1A"

147 267 568 I X 1268"57EG" 1578 "28" 2578 "1A"
148 268 578 I (1278) 1878 "25" 2678 "1A" 4 I i 156 (23) 278 (1A) 678 1 1345 "2B" 2345 "1A" 3456 l 157 345 1 1346 "28" 2346 "1A" 3457 4 158 346 I 1347 "28" 2347 "1A" 3458 4

167 347 I 1348 "25" 2348 "1A" 3467 168 348 I 1356 "2B" 2356 "1A" 3468 I

DE STEAN IRNF VALVE + ANY TRIPLET CONTAINING VALVES I ONE STEAN DUNP VALVE + ANY OUAORUPLET CONTAINING 1 & 2 ( AS IleICATED WITH AN "X" TO THE LEFT ) =6 I VALVES 1 & 2 ( AS INDICATED WITH AN "X" TO 4

TRIPLES + EITHER OF THE INDEPEfGENT FAILURES IN THE I THE LEFT ) = 12 i PARENTHESES TO THE RIsti " 24 I GUARANTEED FAILURES IN PARENTHESES = 3 i I QUADRUPLES + ANY INDEPENDENT FAILURE IN DOUBLE i I QUOTATION NARKS TO THE RIGHT " 96 l

i i

4 1

i

j. Terms 13-15 are similar to terms 10-12 except they involve comon cause failures of MSBIVs.
k. The 16th term assmes automatic failure for comon cause failure of 5 or more MSIVs.
1. The 17th term assumes automatic failure for comon cause failure of 5 or more MSBIVs.
m. The 18th term assumes automatic failure if comon cause failure of 2 or more MSIVs occurs concurrently with the comon cause failure of 2 or more MSBIVs.

Using the failure frequencies from pages 6, 10, and 19:

CD3 = (1.38E-2)[(8E-4){2(2.31E-6) + 2(1/7)(.0423)(.5)(1.52E-3)

+2(f)(.0423)(.5)(.1)(1.52E-3)

+ (2)(h( .0423)( .5)( .9)( .01)(1.52E-3) + 2(1.52E-3)(1.52E-3)}

+ (2)( )(.0423)(.5)(.1)(1.52E-3)2 + (2)( )(.0423)(.5)(.9)(.01)(1.52E-3)

+ (2)( )(.0423)(.5)(.9)(.01)(1.52E-3) + 2(.0423)(.5)(.9)(.99)(1.52E-3)

+ ( .0423)(1.52E-3)( .0423)(1.52E-3)]

CD3 = (1.38E-2)[8E-4{4.62E-6 + 9.19E-6 + 1.84E-6 + 1.98E-7 + 4.62E-6}

+ 1.12E-8 + 2.41 E-9 + 4.96E-8 + 5.729E-5 + 4.134E-9]

CD3 = (1.38E-2)[1.64E-8 + 1.12E-8 + 2.41E-9 + 4.96E-8 + 5.729E-5 + 4.134E-9]

CD3 = (1.38E-2)(5.737E-5) = 7.92E-7 The human error contribution is much higher than this hardware contribution.

D. Effects of an Inoperable MSIV for Plant A:

1. One MSIV inoperable for one full year gives the following tree for MSLBo :

26

FAILURE TO ISOLATE 2 S.G.'s MSA INOPER ABLE (GIVEN MSLBo)

-~

MSIV STEAM MSIV STEAM MSIV STE AM BOTH TRAINS LINE B LINE C LINE D OF ISOLATION FAILS TO CLOSE FAILS TO CLOSE FAILS TO CLOSE LOGIC FAIL i

I TRAIN A TRAIN B ISOLATION ISOLATION LOGIC FAILS LOGIC FAILS O

SLl-A O

SLl B Thus, CD2 = MSLBo [3(%3 + 6%s) + (SLIA)(SLIB)]

= (6.04E-3) [(3)(1.0423)(1.52E-3) + 1.08E-4] = (6.04E-3)(4.86E-3)

= 2.94E-5 One MSIV inoperable for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> in one year results in the following core damage frequency:

4 8756 CD2 = 8760 (2.94E-5) + 8760 (1.325E-6) = 1.34E-6 27 i

i l

One MSIV inoperable for 72 hrs /yr gives the following:

CD2 = 876 (2.94E-5) + 8 (1.325E-6) = 1.56E-6

2. One MSIV inoperable for one full year gives the following tree for SGTR for the S.G. on the steam line that is inoperable:

1/3 SDV's FAIL OR 1 A3 0THER MSIV's Fall TO CLOSE (MSA INOPERABLE)

/\

SGTR PAGE 10 If the SGTR is on one of the other three operable MSIV lines, the MSIV on that line must isolate or you have a failure. Thus, the core damage equation is as follows:

CD + + l+

3" ms ms SDVc ms + ' ms i

= 1/4(1.38E-2)[4.75E-3 + 8.0E-4] + 3/4(1.38E-2)[1.58E-3]

= 1.92E-5 + 1.63E-5 = 3.55E-5 If one MSIV is inoperable for 4 hrs /yr, then CD3 = 8760 (3.55E-5) + ff(1.00E-6)= 1.016E-6 For 72 hrs /yr:

CD3 = 8760 (3.55E-5) + 8688 (1.00E-6) 1.28E-6

=

E. Effects of an Inoperable MSIV for Vogtle:

1. One inoperable MSIV for one full year gives the following tree for an MSLBo (assume the valve is MSA2):

28

l FAILURE TO ISOLATE 2 S.G.'s I MSA2 INOPE R A-BL E (GIVEN MSLBol l l _

l l SLI.A FAILS SLl B FAILS BOTH TR AINS OF 2/4 STEAM AND 1/3 TR AIN B AND 2/4 TRAIN A ISOLATION LINE I.V.'s STE AM LINE 1.V.'s STE AM LINE 1.V.'s LOGIC FAIL FAIL f3 O PAGE PAGE

$ M 30 l l l l 4

TRAIN A 2/4 TRAIN B 1/3 TRAIN B 2/4 TRAIN A ISOLATION STEAM LINE ISOLATION STE AM LINE LOGIC F AILS 1.V/s F All LOGIC F AILS l.V.'s Fall O

SLI.A 3 O

SLIB 2

l I I I I I I STE AM LINE B STEAM LINE C STEAM LINE D STEAM LINE A STEAM LINE B STEAM LINE C STEAM LINE D TRAIN 8 TRAIN B TRAIN B TRAIN A TRAIN A TRAIN A TRAIN A i 1.V.'s FAIL 1.V.'s F All 1.V.'s FAIL 1.V.'s Fall I.V.'s Fall 1.V.'s F AIL 1.V/s FAIL PAGE m o.

I

i 1

5 i

2/4 STE AM LINE I.V.'s F AIL MSA2

, INOPERABLE j O 2/4 l l l 1 I STEAM LINE A STEAM LINE 8 STEAM LINE C STEAM LINE D i TRAIN A TRAINS A AND 8 TRAINS A AND 8 TRAINS A AND 8 l.V.'s FAIL l.V 's Fall 1.V.'s Fall 1.V.'s Fall 4

f3 O F3 o T I T

! I I I I I I

$ STEAM LINE 8 STEAM LINE B STEAM LINE C STEAM LINE C STE AM LINE D STEAM LINE D t TRAIN A TRAIN 8 TRAIN A TRAIN 8 TRAIN A TRAIN 8 4

1.V.'s Fall 1.V.'s FAIL 1.V.'s FAIL 1.V.'s FAIL 1.V.'s Fall 1.V.'s FAIL d

b PAGE b d b b b l , m.

i l

1 1

i 4

The core damage frequency is given by the following equation:

CD2 = MSLB g [(SLIA)(3(A,3 + SA,3) + 3(Amsb + Nmsb)) + (SLIB)(6Ams

+ 6A msb 25 35

+ 12AmsAmsb + 6/7 p(1-y) Ams + g py (1-6) Ams + g Sy4(1-c) Ams

+ 6/7 p(1-y) Amsb + h SY(1-4)Amsb + Sy4(1-c)Amsb)

+ (SLIA)(SLIB) + {3Ams + 31,3 + 9Ams Amsb + I2Ams Amsb

+ 91,3 Amsb + 1 8 A ,3 A + 3A + 12A A msb msb ms msb + 3Amsb }

3 3 18

+ g Dy(1-6)Ams + g Sy(1-6)Amsb + 3 py4(1-c)Ams 18

+ g sy4(1-c) Amsb + Sy6 cams + py6cAmsb + ElmsSAmsb]

a. The first and second terms involve failure of SLIA and an independent failure of 1 of 3 MSIVs or 1 of 3 MSBIVs or any dependent failures of f the MSIVs or MSBIVs.
b. Terms 3-11 are similar to the first nine terms in the equation on page 15 except there are a few more guaranteed failures as shown on page 32.
c. Term no.12 is the failure of both SLIA and SLIB.
d. Terms 13-21 are independent failures listed on page 33.
e. Term 22 is the 3 triple cause failures that guarantee system failure as shown on page 32. Term 23 is similar, but is for the MSBIVs.
f. Term 24 is the 18 quadruple common cause failures that guarantee system failure as shown on page 32. Term 25 is similar, but-is for the MSBIVs.
g. Term 26 is the assumed failure for all common cause failures involving 5 or more MSIVs.
h. Term 27 is the assumed failure for all common cause failures involving 5 or more MSBIVs.
i. The last term is the assumed failure for concurrent common cause failures of 2 or more MSIVs and 2 or more MSBIVs.

31 l

- - . . - - -. - -. , , , - , ~

a. m . -re ---c .~n.v- ~n --, e -

4 i

!\ 8 8! 8*7*6 I I 8\ 8f 8*7*6*5 ls = = 56 I

' = = = 70 (3 j 3l 51 3*2*1 I (4 ) di 4f 4*3*2*1 I

. I CON 8INATIONS OF THREE I CONBINATIONS OF FOUR I

X 123 (178) X 356 I (1234) X 1357 X 2357 (3478) 124 234 X 357 I X 1235 X 1358 X 2358 X 3567 X 125 X 235 X 358 I X 1236 X 1367 X 2367 X 3568 126 236 X 367 I X 1237 X 1368 2368 X 3578 X 127 X 237 368 I X 1238 (1378) X 2378 X 3678 I

i i 128 238 X 378 I X 1245 (14561 2456 X 4567 4 (134) 245 456 I 1246 X 1457 X 2457 4568 3 X 135 246 X 457 I X 1247 X 1458 2458 X 4578 4 X 136 247 458 I 1248 X 1467 2457 4678 j X 137 248 467 I (1256) 1468 2468 (5678)

  • I 3 X 138 256 468 I X 1257 (1478) 2478 X 145 X 257 478 I X 1258 (1567) X 2567 4 W 146 258 X 567 I X 1267 (1568) 2568 I

N X 147 267 568 I 1268 (1578) X 2578 4 148 268 X 578 I (1278) (1678) 2678 4 I (156) 278 678 ,

I (1345) X 2345 (3456)

.! X 157 X 345 I (1346) 2346 X 3457 X 158 348 I (1347) X 2347 X 3458 X 167 X 347 I (1348) 2348 X 3467 l 168 348 I (1356) X 2356 3468 I

1RIARANTEED FAILURES IN PARENTHESES = 3 I GUARANTEED FAILURES IN PARANTHESES = 18 SLI-B FAILURE + TRIPLETS WITH AN "X= TO LEFT = 25 I SLI-B FAILURE + QUADRUPLETS WITH AN "X" TO THE I LEFT = 35 4 I I

1 i

)

i 4

i

}

4 h

Term no.13 3 MSIVs: 1,3,4 1,5,6 1,7,8 Term no. 14 4 MSIVs: 3,4,5,6 3,4,7,8 5,6,7,8 Term no.15 2 MSIVs,1 MSBIV:

1,3,0 1,5,F 1,7,H A,3,4 A,7,8 1,4,C 1,6,E 1,8,G A,5,6 Term no.16 3 MSIVs, 1 MSBIV:

3,4,5,F 3,4,8,G 4,C,5,6 5,6,8,G 3,4,6,E 3,0,5,6 4,C,7,8 5,F,7,8 3,4,7,H 3,0.7,8 5,6,7,H 6,E,7,8 Term no.17 1 MSIV, 2 MSBIVs:

1.C,0, A,3,0 A,6,E 1,E,F, A,4,C A,7,H 1,G,H A,5,F A,8,G Term no.18 2 MSIVs, 2 MSBIVs:

3,4,E,F 3,D,6,E 4,C,6,E 5,F,8,G 7,8,C,D 3,4,G,H 3,D,7,H 4,C,7,H 6,E,7,H 7,8,E,F 5,6,G,H 3,D,8,G 4,C,8,G 6,E,8,G 3,D,5,F 4,C,5,F 5,F,7,H 5,6,C,D Term no.19 3 MSBIVs:

A,C,0 A,G,H A,E,F Term no. 20 1 MSIV, 3 MSBIVs:

3,0,E,F 4,C,E,F 5,F,C,0 6,E,C,0 7,H,C,0 8,G,C,0 3,D,G,H 4,C,G,H 5,F,G,H 6,E,G,H 7,H,E,F 8,G,E,F Term no. 21 4 MSBIVs C,D,E,F C,D,G,H E,F,G,H

! 33

Using the values of the variables referred to on page 19 the core damage frequency is as follows:

CD2 = (6.04E-3)[(9.95E-3)(3(1.584E-3) + 3(1.584E-3))

+ (9.95E-3){6(1.52E-3) + 6(1.52E-3) + 12(1.52E-3)(1.52E-3)

+ 2( )(.0423)(.5)(1.52E-3) + 2( )( .0423)( .5)( .1)(1. 52E-3)

+ 2(h)( .0423)( .5)( .9)( .01)(1.52E-3)} + 1.08E-4

+ {(3+9+9+3)(1.52E-3) + (3+12+18+12+3)(1.52E-3) }

+ 2( )(.0423)(.5)(.1)(1.52E-3) + 2( )(.0423)(.5)(.9)(.01)(1.52E-3)

+ 2( .0423)( .5)(.9)( .99)(1.52E-3) + (.0423) (1.52E-3) ]

= (6.04E-3)[9.458E-5 + (9.95E-3)(1.386E-5 + 1.386E-5

+ 2.772E-5 + 5.511E-5 + 7.65E-6 + 5.8E-7)

+ 1.08E-4 + 8.43E-8 + 2.56E-10 + 9.2E-7 + 2.98E-7

+ 5.729E-5 + 4.134E-9]

CD2 = (6.04E-3)(2.6236E-4) = 1.58E-6 One valve inoperable for 7 days (168 hrs) out of one year results in the following core damage frequency:

CD2 = 87 (1.58E-6) + 76 (1.01E-6) = 1.02E-6

2. One inoperable MSIV for one full year gives the following tree for SGTR for the steam line with the inoperable MSIV (say MSA2 is inoperable):

34

FAILURE TO ISO.

LATE GIVEN TUBE RUPTURE IN STE AM GENER.

ATOR A (MSA2 INOPERABLE) f3 l

l l STEAM LINE A FAIL TO ISOLATE TRAIN A A STEAM DUMP l.V/s Fall VALVE OR 1 OF 3 STEAM LINES A n PAGE rs M

I I F All TO ISOL ATE F All TO ISOLATE 1/3 STE AM DUMP 1 OF 3 REMAIN.

VALVES ING STEAM LINES n

(

-s -

1 I I l F All TO ISOLATE F All TO ISOLATE F AIL TO ISOLATE STEAM LINE B STEAM LINE C STEAM LINE D STEAM DUMP A STEAM DUMP B STE AM DUMP C TRAINS A AND B TRAINS A AND B TRAINS A AND B l.V/s Fall 1.V.'s F All 1.VJS Fall O

SDVe(A)

O SDvelB)

O SDVe(C)

A A A PAGE PAGE PAGE a w w One inoperable MSIV for one full year gives the following tree for SGTR for the steam lines without the inoperable MSIV (say MSB2 inoperable):

35

]

FAILURE TO ISOLATE GIVEN TUBE RUPTURE IN STEAM GENER.

ATOR A iMSB2 INOPE R ABLE)

F3 1 I F All TO ISOL AT E FAILURE TO A STE AM DUMP i ISOLATE VALVE OR 1 OF 3 AFFECTED S.G.

STE AM LINES O [

e

?

I i

f STEAM LINE A STEAM LINE A

' TRAIN A TR AIN B 4

43 1 V.'s Fall 1.V.'s F All PAGE PAGE M M I

F All TO ISOL ATE Fall TO ISOLATE 1 OF 3 REMAIN-f 1/3 ST E AM DUMP ING STE AM LINES VALVES em e a

STEAM LINE B STEAM LINE C STEAM LINE D F AIL TO ISOL ATE F All TO ISOLATE TRAINS A AND B F All TO ISOL ATE STE AM DUMP C TRAIN A TRAINS A AND B STEAM DUMP A STEAM DUMP B 1 V.'s FAIL l.V.'s F All 1.V.'s F All  ;

O O O APAGE-A PAGE APAGE n "=
  • SDVe(A) SDVc(B) SDVc(C) y W 15

The equation for core damage is as follows (neglecting multiple independent failures):

CD3 = 1/4 SGTR [( Ms + D Ms + Amsb + S Msb)(3ASDVc) 3

+ g SY(1-6)Ams 15 3

+ g SY6(1-c) Ams + DY 6cams + H SY(1-6) Amsb 15 6 2 l

+]DY(1-c)Amsb + OY3CAmsb + 0 A ms msbl

+ 3/4 SGTR [(Ams + 2A +0 +0 msb)(3ASDVc) ms msb

  • Amsb ms 1 7

+ g Sy(1-6) Ams + M SY (1-c) 6 Ams + SY cams 6

1 7

+5SY(I-3)Amsb + g Sy6(1-c) Amsb + SY cAmsb 6 + p2A,3 Amsbl The first 11 terms are for the tree on page 35; the last ten terms are for the tree on page 36.

a. Terms 1-4 represent the failure of MSA1 or MSBAl and 1 of the 3 SDVs.
b. Term 5 represents the triple common cause failures of MSIVs on page
38. Term 6 represents quadruple comon cause failures. Term 7 represents tie assumed system failure if 5 or more MSIVs fail due to Comon Cause.
c. Terms 8-10 are similar to terms 3-5 except they are for MSBIV comon cause failures,
d. Term 11 is for 2 or more comon cause failures of MSIVs concurrent with 2 or more MSBIVs (assumed to fail system always).
e. Terms 12-16 are the four combinations for failing to isolate the affected S.G. as well as failing to close one of the three SDVs plus the assumption that any common cause failure fails the system.
f. Terms 13-19 are common cause failures (3s, 4s, >5 for MSIVs; 3s, 4s,

>5 for MSBIVs; 12 MSIVs and 12 MSBIVs).

37

I i

i a

J l f)8 Si

=

8*786

= 56 I

I f 8T i"

Si

=

8*786*5

= 70 l'

3 (3 j 31 51 3*2*1 I (4 j 41 41 4*3*2*1 I

I 1

l COBBINATIONS OF THREE I COMBINATIONS OF FOUR I

(123) X 178 356 I X(1234) 1357 2357 3478 a 124 234 357 I (1235) 1358 2358 3567 i 125 235 358 I (1236) 1367 2367 3568 1 126 236 367 I (1237) 1368 2368 3578 127 237 368 I (1238) X 1378 2378 3678

I
128 238 378 I 1245 X 1456 2456 4567

! X 134 245 456 I 1246 1457 2457 4568 j 135 246 457 I 1247 1458 2458 4578 i' 136 247 458 I 1248 1467 2467 4678 137 248 467 I X(1256) 1468 2468 5678 I

4 138 256 468 I 1257 X 1478 2478 1 145 257 478 I 1258 X 1567 2567 i 146 258 567 I 1267 X 1568 2568 j 147 267 568 I 1268 X 1578 2578 i

$ 148 268 578 I I

X(1278) X 1878 2678 X 156 278 678 I X 1345 2345 3456 157 345 I X 1346 2346 3457 158 346 I X 1347 2347 3458 j 167 347 I X 1348 2348 3467 j 168 348 I X 1356 2356 3468 1 I i

GIVEN THE AFFECTED STEAN GENERATOR IS "A" : I IF THE INDPERA6LE NSIV IS "NSA2" OR P8JNBER "2", THEN I IF THE INOPERASLE NSIV IS "NSA2" OR "2", THEN THE 15 THE 3 TRIPLETS WITH AN "X" TO THE RICHT ARE FAILURES. I QUADRUPLETS WITH AN "X" TO THE RIGHT ARE FAILURES.

i I j IF THE INDPERA6LE NSIV IS "NS82" OR NUMBER "4", I IF THE INDPERABLE NSIV IS *NS82" OR "4", THEN THE 7 i THEN THE TRIPLET IN PARENTHESES IS A FAILURE. I QUADRUPLETS IN PARENTHESES ARE FAILURES.

i I

i 4

I

Using the failure frequencies from pages 6,10, and 19:

CD3 = 1/4(1.38E-2)[1.584E-3 + 1.584E-3)(8.0E-4)

+ 2( )(.0423)(.5)(.1)(1.52E-3)+ 2( )(.0423)(.5)(.9)(.01)(1.52E-3)

+ 2( .0423)( .5)( .9)( .99)(1.52E-3) + ( .0423)2 (1.52E-3)2]

+3/4(1.38E-2)[{4(1.52E-3)2 + 2(.0423)(1.52E-3)}(8E-4)

+ 2( )(.0423)(.5)(.1)(1.52E-3) + 2( )(.0423)(.5)(.9)(.01)(1.52E-3)

+ 2( .0423)( .5)( .9)( .99)(1.52E-3) + ( .0423)2 (1.52E-3)2]

CD3 = 1/4(1.38E-2)[2.53E-6 + 9.2E-7 + 2.5E-7 + 5.729E-5 + 4.13E-9]

+ 3/4(1.38E-2)[1.lE-7 + 3.1E-7 + 1.2E-7 + 5.729E-5 + 4.13E-9]

CD3 = 1/4(1.38E-2)(6.099E-5) + 3/4(1.38E-2)(5.783E-5)

CD3= 8.09E-7 One valve inoperable for 7 days (168 hrs) out of one year leads to the following core damage frequency:

CD3 = 87 0 (8.09E-7) + 8 (7.92E-7) = 7.923E-7 F. Effects of 2 inoperable MSIVs for Vogtle:

1. Two inoperable MSIVs on one system steam line for one full year gives the following tree for an MSLB o:

l 39

4 1

FAILURE TO ISO.

L ATE 2 S G.'s (GIVEN MSLBo)

MSA1 AND MSA2 INOPERABLE i (T 1 I I I SLI A FAILS SLI 8 FAILS BOTH TR AINS OF 1/3 STE AM AND 1/3 TRAIN 8 AND 1/3 TRAIN A ISOLATJON STE AM LINE 1.V/s LINF.1.V/s STE AM LINE I.V/s LOGIC FAIL FAIL i

PAGE PAGE o #

43 I I I I TRAIN A 1/3 TRAIN 8 TRAIN 8 1/3 TRAlN A 4 ISOLATION STE AM LINE ISOLATION STEAM LINE LOGIC FAILS 1.V/s F All LOGIC FAILS 1.V/s FAIL j

I I l l

, STE AM LINE B STE AM LINE C STEAM LINE D STEAM LINE 8 TR AIN 8 STEAM LINE C STE AM LINE D TRAIN 8 TR AIN 8 TRAIN A TRAIN A TRAIN A l.V/s F All I.V/s Fall 1.V/s FAIL 1.V/s Fall 1.V/s FAIL 9 1.V/s Fall

' A PAGE A A A A A y siin.4 1

1/3 STEAM LINE 1.V.'s D\ Fall em STEAM LINE B STEAM LINE C STEAM LINE D TRAINS A AND B TRAINS A AND B TRAINS A AND B 1.V.'s Fall 1.V.'s Fall I. V.'s Fall PAGE PAGE PAGE 231,o 4 15 15 15 I

l 41 l

_ _ _ . _ _ . _ - . _ _ ____ _ . . , . _ . - _ _ _ _ , _ _ _ . . _ . _ . _ - . . . ~ . . - _ . . _ . _ . . . . _ . _ _ .

.. . ~_ . - - -.

L i

The equation for core damage is:

CD2

- MSLB [(SLIA + SLIB) {3(A + SA ) + 3(Ag + sag )}

+ (SLIB)(SLIB) + {3 A,3 + 6 1,3 msbA + 3Amsb }

+ f p(1-Y) Ams + SY(1-6)Ams + SY6 (1-c)Ams + SY 6cams

+ f S(1-Y) Amsb + SY(1-3)Amsb + OYE (I-8)Amsb + Sy6ckmsb

+ p2 x ,3xmsbl 4

1 a. Terms 1-4 are failures of SLIA or SLIB and a failure of an MSIV or an i MSBIV.

b. Term 5 is failure of both SLIA and SLIB.
c. Terms 6-9 are independent failures to isolate steam line B, C, or D.

1 d. Terms 10-13 are common cause failures of MSIVs (see page 43).

e. Terms 14-17 are common cause failures of MSBIVs (see page 43).

) f. The last term is a common cause failure of 22 MSIVs and 12 MSBIVs.

i Using failure frequencies from pages 6, 8, and 19 gives the following:

CD2 = (6.04E-3)[9.95E-3 + 9.95E-3) {6(1.584E-3)} + 1.08E-4

+ {l2(1.52E-3)2} + 2(3/7)(.0423)(.5)(1.52E-3)

+ 2( )(.0423)(.5)(.1)(1.52E-3) + 2( )( .0423)( .5)( .9)( .01 )(1. 52E-3)

+ 2(.0423)(.5)(.9)(.99)(1.52E-3) + (.0423)2 (1.52E-3)2]

CD2 = (6.04E-3)[1.891E-4 + 1.08E-4.+ 2.77E-5 + 2.756E-5

+ 5.51E-6 + 6.9E-7 + 5.729E-5 + 4.13E-9]

= (6.04E-3)(4.159E-4) = 2.51E-6 If one steam line is inoperable (i.e., 2 MSIVs in the steam line or 2 MSBIVs) for 4 hrs /yr, then the core damage f requency is given by the following:

CD2 " 8760 (2.51E-6) + (1.01E-6) = 1.011E-6 One steam line inoperable 72 hrs /yr gives:

CD 2 " 876 (2.51E-6) + (1.01E-6) = 1.022E-6 42 l

m wm l J" I 8) 81 887*6 I [8 I 8f

=

8*7*6*5 I = = = 56 I l= = 70 (3) 31 51 3*S*1 (4j 41 41 4*3*2*1 I

I CONBINATIONS OF THREE I COMBINATIONS OF FOUR I

l 123 X 178 X 356 I X 1234 1357 2357 X 3478 124 X 234 357 I 1235 1358 2358 X 3567 125 235 358 I 1236 1367 2367 X 3568 126 236 367 I 1237 1368 2368 X 3578 127 237 368 I 1238 X 1378 X 2378 X 3678 I

128 238 X 378 I 1245 X 1456 X 2456 X 4567 X 134 245 X 456 I 1246 1457 2457 X 4568 135 246 457 I 1247 1458 2458 X 4578 136 247 458 I 1248 1467 2467 X 4678 '

137 248 467 I X 1256 1468 2468 X 5678 l I

138 X 256 468 I 1257 X 1478 X 2478

    • 145 257 X 478 I 1258 X 1567 X 2567 LJ 146 258 X 567 I 1267 X 1568 X 2568 147 267 X 568 I 1268 X 1578 X 2578 148 268 X 578 I X 1278 X 1878 X 2678 I

X 156 X 278 X 678 I X 1345 X 2345 X 3456 157 X 345 I X 1346 X 2346 X 3457 158 X 348 I X 1347 X 2347 X 3458 167 X 347 I X 1348 X 2348 X 3467 168 X 348 I X 1350 X 2356 X 3468 i I

IF BOTH NSIV'S IN STEAN LINE A ARE INOPERABLE, THEN I IF BOTH NSIV'S IN STEAN LINE A ARE INDPERABLE. THEN THE 18 TRIPLETS WITH AN "X" TO THE RIGHT ARE I THE 42 QUADRUPLETS WITH AN "X" TO THE RIGHT ARE FAILURES. I FAILURES.

I I

i i

2. Two inoperable MSIVs on one steam line for one full year gives the following tree for an SGTR (if the affected S.G. is on the inoperable line):

1 FAILURE TO ISOLATE GIVEN TUBE RUPTURE S.G. A; MSA1 AND MSA2 INOPER ABLE I I F AIL TO ISOLATE Fall TO ISOLATE 1/3 M vE I TE M L ES A

e em I I I I STEAM LINE B STEAM LINE C STEAM LINE D F AIL TO ISOLATE F AIL TO ISOLATE Fall TO ISOLATE TRAINS NDB ST EAM DUMP B STEAM DUMP C TR N NDB TRAINS A DB STEAM DUMP A O

SDVe(A)

O SOVe(B)

O SDVe(C)

APAGE APAGE APAGE a a u l

t

' If the affected S.G. is on one of the 3 operable lines, that line must isolate or you have a failure.

i AFFECTED S.G.

l A FAILS TO ISOLATE;MSB1 ,

AND MSB2 INOPERABLE f3 i

I STEAM LINE A STEAM LINE A TRAIN A TRAIN B 1.V.'s Fall 1.V.'s FAIL AA AB PAGE PAGE i 14 14 44 1

l I

The expression for core damage is as follows:

CD3 = 1/4 SGTR [3ASDVc + {3A,3 + 61ms msb + 3Amsb }

18 42

+ 3/7 p(1-y) Ams + pi BY(1-6) Ams + g DY (1-c) 6 Ams + SY cams 6 18 42 6

+ 3/7 $(1-y)Msb + 5 SY(I-3) Amsb + 5 SY (I-8)Amsb + sy6ckmsb + p2 A ,3 Amsbl

+ 3/4 SGTR [Ams

  • 2hms msb + msb

+ 1/7 S(1-Y) Ams + SY(1-6)Ams+hBY4(1-c)Ams+SY6ckms

+1/7S(1-Y)Amsb+hsy(1-6)Amsb+ HEY (1c)Amsb+SYcAmsb 6 6

&S A ms Amsb l The first 13 terms are for the first tree on page 44 and the last 12 terms are for the second tree on page 44.

a. Term 1 is failure of 1 of the 3 SDVs.
b. Terms 2-4 are for independent failure combinations of the MSIVs and MSBIVs.
c. Terms 5-8 are common cause failures of the MSIVs (page 46).
d. Terms 9-12 are common cause failures of the MSBIVs (page 46).
e. Term 13 is 12 MSIV and 22 MSBIV common cause failures.
f. Terms 14-16 are the independent failure combinations for the affected

! S.G.

g. Terms 17-2 are common cause failures for MSIVs and MSBIVs (page 46).

Using the failure frequencies on pages 6,10, and 19:

CD3 = 1/4(1.38E-2)[8E-4 + {12(1.52E-3) }

+ 2(3/7)(.0423)(.5)(1.52E-3) + 2(2 )(.0423)(.5)(.1)(1.52E-3)

+ 2( )(.0423)(.5)(.9)(.01)(1.52E-3) l 45

n. . . . _ . _ _

I 8\ =

81

=

887*6

= 56 I I8I

=

81

=

8*7*685

= 70 l I l (3j 31 51 3*2*1 (4 j 41 41 4*3*2*1 I

I COMBINATIONS OF THREE I COM81 NATIONS OF FOUR I

(123) X 178 X 356 I X(1234) 1357 2357 X 3478 (124) X 234 357 I (1235) 1358 2358 X 3567 (125) 235 358 I (1236) 1367 2367 X 3568 (126) 236 367 I (1237) 1368 2368 X 3578 (127) 237 368 I (1238) X 1378 X 2378 X 3678 I

(128) 238 X 378 I (1245) X 1456 X 2456 X 4567 X 134 245 X 456 I (1246) 1457 2457 X 4568 135 246 457 I (1247) 1458 2458 X 4578 136 247 458 I (1248) 1467 2467 X 4678 137 248 467 I X(1256) 1468 2468 X 5678 I

138 X 256 468 I (1257) X 1478 X 2478 145 257 X 478 I (1258) X 1567 X 2567 146 258 X 567 I (1267) X 1568 X 2568 4, 147 267 X 568 I (1268)' X 1578 X 2578 en 148 268 X 578 I X(1278) X 1678 X 2678 I

X 156 X 278 X 678 I X 1345 X 2345 X 3456 157 X 345 I X 1346 X 2346 X 3457 158 X 346 I X 1347 X 2347 X 3458 167 X 347 I X 1348 X 2348 X 3467 '

168 X 348 . I X 135G X 2356 X 3468 I

ASSUME THE AFFECTED STEAN GENERATOR IS "A". I IF MSA1 Afe NSA2 (MSIV's 1 & 2) ARE IN0PERA8LE. I IF NSA1 AND MSA2 (MSIV'S 1 & 2) ARE INDPERABLE.

THEN THE 18 TRIPLETS WITH AN "X" TO THE LEFT I THEN THE 42 QUADRUPLETS WITH AN 'X" TO THE LEFT ARE FAILURES. I ARE FAILURES.

I I

IF MS81 APS MS82 (MSIV'S 3 & 4) ARE INOPERA8LE, I IF MS81 AND MSB2 (MSIV'S 3 A 4) ARE IN0PERA8LE, THEN THE 6 TRIPLETS IN PAKENTHESES ARE FAILURES. I THEN THE 15 QUADRUPLETS IN PARENTHESES ARE FAILURES.

I I

_ _ _ _ _ _ d

+ 2(.0423)(.5)(.9)(.99)(1.52E-3) + (.0423)2 (1.52E-3)2]

+ 3/4(1.38E-2)[4(1.52E-3)2 + 2(1/7)( .0423)( .5)(1.52E-3)

+ 2( )(.0423)(.5)(.1)(1.52E-3) + 2( )(.0423)(.5)(.1)(1.52E-3)

+ 2(.0423)(.5)(.9)(.99)(1.52E-3) + (.0423) (1.52E-3) ]

CD3 = 1/4(1.38E-2)[8E4 + 2.772E-5 + 2.756E-5

+ 5.51E-6 + 6.9E-7 + 5.729E-5 + 4.13E-9]

+ 3/4(1.38E-2)[9.24E-6 + 9.19E-6 + 1.84E-6 + 2.76E-6 + 5.729E-5 + 4.13E-9]

CD3 = 1/4(1.38E-2)(9.188E-4) + 3/4(1.38E-2)(8.03E-5)

CD3= 4.00E-6 For 1 steam line inoperable 4 hrs /yr:

CD3 = 8760(4.00E-6) + (7.92E-7) = 7.935E-7 For 1 steam line inoperable 72 hrs /yr:

CD3 = 8760(4.00E-6) + (7.92E-7) = 8.18E-7~

0642V 47 I

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