ML112990219
| ML112990219 | |
| Person / Time | |
|---|---|
| Site: | Monticello |
| Issue date: | 02/23/1979 |
| From: | Northern States Power Co |
| To: | |
| Shared Package | |
| ML112990218 | List: |
| References | |
| NUDOCS 7903020346 | |
| Download: ML112990219 (18) | |
Text
7903020 3'fgC NUMBER OF PERSONNEL (lOO mrem)
TOTAL MAN-REM CONTRACT CONTRACT STATION UTILITY WORKERS AND STATION UTILITY WORKERS AND WORK & JOB FUNCTION EMPLOYEES EMPLOYEES OTHERS EMPLOYEES EMPLOYEES OTHERS REACTOR OPERATIONS & SURVEILLANCE OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR. PERSONNEL INSTRUMENT & CONTROLS PERSONNEL SECURITY ROUTINE MAINTENANCE MAINTENANCE PERSONNEL INSERVICE INSPECTION HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR.
PERSONNEL INSTRUMENT & CONTROLS PERSONNEL MAINTENANCE PERSONNEL
- SPECIAL MAINTENANCE OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR. PERSONNEL INSTRUMENT &.CONTROLS PERSONNEL MAINTENANCE PERSONNEL WASTE PROCESSING OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR. PERSONNEL INSTRUMENT & CONTROLS PERSONNEL MAINTENANCE PERSONNEL REFUELING OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR. PERSONNEL INSTRUMENT & CONTROLS PERSONNEL MAINTENANCE PERSONNEL
- TOTAL OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR. PERSONNEL INSTRUMENT & CONTROLS PERSONNEL MAINTENANCE PERSONNEL SECURITY PERSONNEL 33 7
24 7
0 29 0
0 0
0 33 7
18 7
27 20 6
5 3
25 19 1
5 3
15 105 21 52 20 96 0
0 0
3 0
0 59 0
1 0
1 0
0 3
0 67 0
0 0
0 2
0 0
1 0
24 0
0 8
0 153 0
2 24 8
14 2
157 0
0 10 19 0
15 11 16 179 7
1 0
1 12 0
1 5
0 16 9
41 24 41 383 2
32.075 8.523 5.820 4.491 0
23.757 0
0 0
0 9.138 1.240 5.753 2.576 21.637 3.914
.871
.215
.098 14.110 2.366
.049
.231
.034 1.557 47.493 10.683 12.019 7.199 61.061
.000 0
0
.501 0
0 9.810 0
.128 0
.009 0
0
.777 0
44.027 0
0 0
0
.098 0
0
.009 0
1.729
.000
.000 1.415
.000 55.673
.000
.310 4.205
.896 1.079
.205 23.035 0
0 11.851 15.899 0
5.451 2.709 13.956 66.949 4.441
.004 0
.039
.837 0
.009 1.045 0
.737 4.751 9.669 4.650 26.925 107.457
.205 GRAND TOTAL:
294 161 500 138.455 57.088 153.657
- DESCRIPTION: 1. Maintenance performed
- 2.
Torus Modification in Primary Containment during shutdown.
- 3. Security and Fire Protection Systems
- 4. Radwaste System Modification
- 5. Main Steam Line Modification
- INDIVIDUALS MAY BE LISTED UNDER MORE THAN ONE WORK AND JOB FUNCTION.
80 0
in tmi 00-Installation
- 6. Fuel Pool Modification
MONTICELLO NUCLEAR GENERATING PLANT ANNUAL REPORT OF CHANGES, TESTS, AND EXPERIMENTS 1978 The following sections include a brief description and a summary of the safety evaluation for those changes, tests and experiments which were carried out without prior NRC approval, pursuant to the requirements of 10CFR50.59(b).
- 1.
INCREASE ALLOWABLE NUMBER OF REACTOR VESSEL STARTUP/SHUTDOWN CYCLES TO 298 (SRI 181)
Description of Change The allowable number of reactor vessel startup/shutdown cycles was increased from 120 to 298.
Summary of Safety Evaluation A review of the Monticello Reactor Vessel Design Specification and Stress Report indicates that the controlling usage factor in the vessel (with the exception of the feedwater nozzle for which the design cycling has been substantially redefined) is 0.67 after 200 cycles in the refueling bellows support skirt.
Thus an increase in the allowable number of cycles to 298 (200/0.67) is justified.
- 2. REDESIGNATION OF LPCI AND CORE SPRAY ISOLATION VALVES (SRI 184)
Description of Change The core spray injection line isolation valves have been redefined to be the motor operated valves outboard of primary containment M 3 1751/1752, MO 1753/1754). The LPCI injection line valves are no longer considered to be primary containment isolation valves.
Summary of Safety Evaluation The redesignation of the core spray isolation valves is based on the ability of the operator to manually close the valves in the event of a failure of the pump to start or the tripping of the pump during an accident situation. The deletion of the LPCI isolation valves is based on the fact that the injection lines are pressurized under all circumstances following an accident and effectively provided with a sealing system. This is consistent with NRC positions presented at a meeting in Bethesda on October 28, 1976.
- 3. INSTALLATION OF HIGH DENSITY FUEL RACKS (77Z013 Addendum III)
Description of Change Four High Density Fuel Storage System (HDFSS) modules were installed in the spent fuel storage pool per License Amendment No. 34 issued by the NRC on April 14, 1978. Visual inspection of the installed modules revealed that some of the tubes had swollen. Two vent holes were drilled in the top of the tube to relieve pressure found to be causing the swelling.
Summary of Safety Evaluation Tube venting precludes the possibility of tube inner wall bulging caused by air/water entrapment within the boral sandwich. Also, any hydrogen generated within the tube is relieved.
The results of testing conducted by both the tube manufacturer and the module supplier indicate minimal galvanic corrosion between aluminum and stainless steel over the expected life of the modules. This results in acceptable boral stability in the fuel pool environment within the tube sandwich.
9
- 4. ATWS MODIFICATION (77Z024)
Description of Change To mitigate the consequences of an Anticipated Transient Without Scram (ATWS) event, a system was installed to trip the reactor recirc pumps upon detection of an ATWS event as indicated by high reactor pressure or low reactor water level.
Summary of Safety Evaluation The performance of the recirc pump trip system in mitigating the consequences of an ATWS event was analyzed and found accept able (ref: GE Document NEDO 25016, submitted to NRC, DOR on September 15, 1976).
Installation of the system does not create an unanalyzed condition, change the conclusions of any previous plant analysis or degrade any existing system.
- 5. LOAD MITIGATING SPARGERS (78MD12)
Description of Change The rams heads on the B, C, D, F and H safety/relief valve discharge lines were replaced with load mitigating spargers.
Summary of Safety Evaluation Aspects of this modification which could conceivably affect the probability or consequences of an accident or malfunction previously analyzed were evaluated. The quencher is designed to result in an acceptable pressure drop and thereby eliminate feedback to the safety/
relief valve. Neither the safety/relief valve nor nuclear steam supply system is affected by the modification.
Effects of the quencher on the piping has been specifically accounted for in the quencher and support design. The loads on containment with the existing ramshead were measured during relief valve testing at Monticello during June, 1976, and the structural adequacy of the containment was demonstrated. Testing conducted in December, 1977 demonstrated that loads from quencher operation are less than loads from ramshead operation.
- 6. SHORTEN TORUS VENT HEADER DOWNCOMERS [78M014]
Description of Change The torus vent header downcomers minimum submergence was reduced from 4'-6 1/2" to 3' and lateral restraints were added to further reduce stresses on the vent header.
Summary of Safety Evaluation General Electric Mark I Containment Tests demonstrate that at three feet submergence the downcomer will perform as required during postulated events.
- 7. INSTALLATION OF TORUS VENT HEADER DEFLECTOR [78M015]
Description of Change A vent header deflector was installed under the vent header to reduce the water impact loads on the vent header during postulated events. The deflector consists of a 14-inch schedule 160 steel pipe with 6-inch structural steel tees welded to the pipe at a 450 angle from the horizontal. The deflector is supported by plate attached to the vent header collar. The deflector is located on the vertical centerline of the vent header with a distance of 22 inches between the top of the deflector and the bottom of the vent headers.
Summary of Safety Evaluation This modification reduces the stresses on existing plant equipment and the deflector stresses are below code allowable under all postu lated conditions. The deflector was designed according to ASME Section III and installed according to the AISC Manual of Steel Construction.
- 8. MAIN STEAM LINE MANIFOLD (78Z028)
Description of Change An 18 inch equalizer line was installed to facilitate testing of the turbine stop valves while the plant is at 100% power. Because of new loads identified with turbine stop valve fast closure, 10 new steamline supports were added and 8 existing supports were modified. Also, hangers were modified and added to the existing bypass lines.
Summary of Safety Evaluation This modification does not introduce new anchor points or govern ing stress points. The new and modified hangers reduce the calcu lated pipe stresses. This modification meets applicable requirements of ASME Section III and ANSI B31.1.
Description of Change The LPCI recirc loop selection logic was modified so that the recirc pump suction valve in the selected loop does not receive a signal to close. Problems with #11 recirc pump discharge bypass valve required that the interlock be reinstalled on the suction valve and removed from the discharge and discharge bypass valves. The interlocks will be returned to the discharge valves after repairs can be made to the discharge bypass valve.
Summary of Safety Evaluation This modification assures that a break between the recirc pump isolation valves will depressurize the reactor vessel so that low pressure ECCS systems can provide core cooling. One of the recirc pump discharge valves will still close upon LPCI initiation providing the correct path of coolant to the vessel.
- 10.
CHANGES TO MONTICELLO SEGMENTED TEST ROD (STR)
BUNDLE FOR CYCLE 7 OPERATION (78072)
Description of Change Six irradiated segmented rods were removed from the bundle. Fresh unirradiated rods, each containing four new segments replaced the removed rods. The locations of three pairs of STR fuel rods were exchanged to satisfy the nuclear criteria for local peaking.
Summary of Safety Evaluation This modification has no significant affect on the thermal mechanical, or nuclear characteristics of the STR bundle. The results of the safety analysis contained in GE Document NEDE 20179 are not affected.
- 11. CORE SPRAY ISOLATION VALVE BYPASS SWITCH (78MO75)
Description of Change To conform with SRI #184 (reported above), the core spray outboard isolation valves 0l0-1751 and MD-1752) control circuits were modified. Key locked bypass switches were installed to allow closure of the outboard isolation valve if a core spray pump fails to start or trips after receiving an auto initiation signal. This modification allows operation of these valves for containment isolation purposes.
0 0
Summary of Safety Evaluation The consequences of bypass switch failure were analyzed. A failure of either of these switches would not result in system degradation beyond that previously considered in the accident analysis.
REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIOS)
ACCEssION NBR:79U3020343 0OC.OATE: 79/02/23 NOTARIZED: NO FACIL:50-2b3 MONTICELLO NUCLEAR GENERATIN1G
- PLANT, NORTHERN STATES AUTH.NAME AUTHOR AFFILIATIONJ MAYER,L.O.
NORTHERN STATES POAER CO.
RECiP.NAME RECIPIENT AFFILIATION KEPPLEk,J.G.
REGION 3, CHICAGO, OFFICE OF THE DIRECTOR DOCKET 4 050002b3
SUBJECT:
FORNAROS ANNUAL REPTS OF OCCUPATIONAL EXPOSURE,CHANGES, TESTS & EXPERIMENTS.
DISTRI8UTION CODE: A008S COPIES RECEIVED:LTR J ENCL J SIZE: /t'>?
TITLE: AiNNUAL, SEMI-ANNUAL & MONTHLY OPERATING REPORTS (OL STAG NOTES:
RECIPIENT ID CODE/NAME ACTION:
05 C-COPIES LTTR ENCL 6
b RECIPIENT ID CO0E/NAME COPIES LTrR ENCL INTERNAL:
EXTERNAL:
11 18 20 22 REG FILE I & E DIR DOR ENGR BR PLANT SYS BR CORE PERF BR 03 LPOR 24 NATL LAB 26 ACRS 1
2 1
1 I
1 2
1 15 02 14 17 19 21 23 1
2 1
1 1
1 2
1 15 NRC POR MPA AD SYS/PROJ REAC SAFT 6R EE8 EFFL TR SYS 04 NSIC 25 BROOKHAVEN TOTAL NUMBER OF COPIES REQUIRED: LTTR 1I 2
1 1
1 1
1 2
1 1
1 1
1 1
1 1
40 ENCL 40
NORTHERN STATES POWER COMPANY MINNEAPOLIS, MINNESOTA 55401 February 23, 1979 Mr J G Keppler, Director, Region III Office of Inspection & Enforcement U S Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137
Dear Mr Keppler:
MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Annual Report of Occupational Exposure
- 7d Changes, Tests & Experiments January 1 -
December 31, 1978 Attached you will find two copies of the following reports:
- 1) Annual Report of Occupational Exposure
- 2) Annual Report of Changes, Tests, and Experiments These reports satisfy the annual reporting requirements contained in Section 6.7.A.2 of Appendix A to DPR-22 and Section 50.59(b) of 10CFR Part 50.
Yours very truly, L 0 Mayer, PE Manager of Nuclear Support Services LOM/DHM/deh cc:
Director, 1E, USNRC (c/o DSB) (40)
G Charnoff MPCA Attn:
J W Ferman 2 6 1979 Attachment 7903020 J4*
7903020 3'fgg WORK & TOE FIH.ICT ION NUMBER.
STATION EMPLOYEES OF PERSONNEL UTILITY EMPLOYEES (Z100 inrem)
CONTRACT WORKERS AND OTHERS 11 TOTAL MAN-REM STATION EMPLOYEES UTILITY EMPLOYEES CONTRACT WORKERS AND OTHERS REACTOR OPERATIONS & SURVEILLANCE OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR.
PERSONNEL INSTRUMENT & CONTROLS PERSONNEL SECURITY ROUTINE MAINTENANCE MAINTENANCE PERSONNEL INSERVICE INSPECTION HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR.
PERSONNEL INSTRUMENT & CONTROLS PERSONNEL MAINTENANCE PERSONNEL
- SPECIAL MAINTENANCE OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR. PERSONNEL INSTRUMENT & CONTROLS PERSONNEL MAINTENANCE PERSONNEL WASTE PROCESSING OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR. PERSONNEL INSTRUMENT & CONTROLS PERSONNEL MAINTENANCE PERSONNEL REFUELING OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR. PERSONNEL INSTRUMENT & CONTROLS PERSONNEL MAINTENANCE PERSONNEL
- TOTAL OPERATING PERSONNEL HEALTH PHYSICS PERSONNEL SUPERVISORY & ENGR.
PERSONNEL INSTRUMENT & CONTROLS PERSONNEL MAINTENANCE PERSONNEL SECURITY PERSONNEL GRAND TOTAL:
ll_
- DESCRIPTIONt
- 1. Maintenance performed 33 7
24 7
0 29 0
0 0
0 33 7
18 7
27 20 6
5 3
25 19 1
5 3
15 105 21 52 20 96 0
0 0
3 0
0 59 0
1 0
1 0
0 3
0 67 0
0 0
0 2
0 0
1 0
24 0
0 8
0 153 0
2 24 8
14 2
157 0
0 10 19 0
15 11 16 179 7
1 0
1 12 0
1 5
0 16 9
41 24 41 383 2
32.075 8.523 5.820 4.491 0
23.757 0
0 0
0 9.138 1.240 5.753 2.576 21.637 3.914
.871
.215
.098 14.110 2.366
.049
.231
.034 1.557 47.493 10.683 12.019 7.199 61.061
.000 0
0
.501 0
0 9.810 0
.128 0
.009 0
0
.777 0
44.027 0
0 0
0
.098 0
0
.009 0
1.729
.000
.000 1.415
.000 55.673
.000 a*
I I
I I
294 161 500 in Primary Containment dui-Ing shutdown.
l 138.455 Torus Modification
- 3. Security and Fire Protection Systems
- 4.
Radwaste System Modification
- 5.
Main Steam Line Modification
- 6.
- INDIVIDUALS MAY BE LISTED UNDER MORE THAN ONE WORK AND JOB FUNCTION.
57.088
.310 4.205
.896 1.079
.205 23.035 0
0 11.851 15.899 0
5.451 2.709 13.956 66.949 4.441
.004 0
.039
.837 0
.009 1.045 0
.737 4.751 9.669 4.650 26.925 107.457
.205 153.657 00 F"
00 on0 0
F-3 0
00 Installation Fuel Pool Modification
MONTICELLO NUCLEAR GENERATING PLANT ANNUAL REPORT OF CHANGES, TESTS, AND EXPERINMENTS 1978 The following sections include a brief description and a summary of the safety evaluation for those changes, tests and experiments which were carried out without prior NRC approval, pursuant to the requirements of 10CFR50.S9(b).
- 1.
INCREASE ALLOWABLE NUMBER OF REACTOR VESSEL STARTUP/SHUTDOWN CYCLES TO 298 (SRI 181)
Description of Change The allowable number of reactor vessel startup/shutdown cycles was increased from 120 to 298.
Summary of Safety Evaluation A review of the Monticello Reactor Vessel Design Specification and Stress Report indicates that the controlling usage factor in the vessel (with the exception of the feedwater nozzle for which the design cycling has been substantially redefined) is 0.67 after 200 cycles in the refueling bellows support skirt.
Thus an increase in the allowable number of cycles to 298 (200/0.67) is justified.
- 2. REDESIGNATION 0. LPCI AND CORE SPRAY ISOLATION VALVES (SRI 184)
Description of Change The core spray injection line isolation valves have been redefined to be the motor operated valves outboard of primary containment 74 1751/1752, MO 1753/1754). The LPCI injection line valves are no longer considered to be primary containment isolation valves.
Summary of Safety Evaluation The redesignation of the core spray isolation valves is based on the ability of the operator to manually close the valves in the event of a failure of the pump to start or the tripping of the pump during an accident situation. The deletion of the LPCI isolation valves is based on the fact that the injection lines are pressurized under all circumstances following an accident and effectively provided with a sealing system.
This is consistent with NRC positions presented at a meeting in Bethesda on October 28, 1976.
- 3. INSTALLATION OF HIGH DENSITY FUEL RACKS (77Z013 Addendum III)
Description of Change Four High Density Fuel Storage System (HDFSS) modules were installed in the spent fuel storage pool per License Amendment No. 34 issued by the NRC on April 14, 1978. Visual inspection of the installed modules revealed that some of the tubes had swollen. Two vent holes were drilled in the top of the tube to relieve pressure found to be causing the swelling.
Summary of Safety Evaluation Tube venting precludes the possibility of tube inr wall bulging caused by air/water entrapment within the boral sandwich. Also, any hydrogen generated within the tube is relieved. The results of testing conducted by both the tube manufacturer and the module supplier indicate minimal galvanic corrosion between aluminum and stainless steel over the expected life of the modules.
This results in acceptable boral stability in the fuel pool environment within the tube sandwich.
- 4.
ATWS MODIFICATION (77"024)
Description of Change To mitigate the consequences of an Anticipated Transient Without Scram (ATWS) event, a system was installed to trip the reactor recirc pumps upon detection of an ATWS (vent as indicated by high reactor pressure or low reactor water level.
Sumary of Safety Evaluation The performance of the recirc pump trip system in mitigating the consequences of an ATWS event was analyzed and found accept able (ref: GE Document NEDO 25016, submitted to NRC, DOR on September 15, 1976).
Installation of the system does not create an unanal, zed condition, change the conclusions of any previous plant analysis or degrade any existing system.
- 5. LOAD MITIGATING SPARGERS (78M012)
Description of Change The rams heads on the B, C, D, F and H safety/relief valve discharge lines were replaced with load mitigating spargers.
Summary of Safety Evaluation Aspects of this modification which could conzeivably affect the probability or consequences of an accident or malfunction previously analyzed were evaluated.
The quencher is designed to result in an acceptable pressure drop and thereby eliminate feedback to the safetz relief valve.
Neither the safety/relief valve nor nuclear steam sup.
system is affected by the modification.
Effects of the quencher on the piping has been specifically accounted for in the quencher and support design.
The loads on containment with the existing ramshead were measured during relief valve testing at Monticello during June, 1976, and the structural adequacy of the containment was demonstrated. Testing conducted in December, 1977 demonstrated that loads from quencher operation are less than loads from ramshead operation.
- 6.
SHORTEN TORUS VENT [EADER DOWNCOMERS [78M 014]
Description of Change The torus vent header downcomers minimun submergence was reduced from 4'-6 1/2" to 3' and lateral restraints were added to further reduce stresses on the vent header.
Summary of Safety Evaluation General Electric Mark I Containment Tests demonstrate that at three feet submergence the downcomer will perform as required during postulated events.
- 7. INSTALLATION OF TORUS VENT HEADER DEFLECTOR [78M015]
Description of Change A vent header deflector was installed under the vent header to reduce the water impact loads on the vent header during postulated events. The deflector consists of a 14-inch schedule 160 steel pipe with 6-inch structural steel tees welded to the pipe at a 450 angle from the horizontal. The deflector is supported by plate attached to the vent header collar. The deflector is located on the vertical centerline of the vent header with a distance of 22 inches between the top of the deflector and the bottom of the vent headers.
Saumary of Safety Evaluation This modification reduces the stresses on existing plant equipment and the deflector stresses are below code allowable under all postu lated conditions. The deflector was designed according to.ASME Section III and installed according to the AISC Manual of Steel Construction.
- 8.
NLAIN STEAM LINE MANIFOLD (78Z028)
Description of Change An 18 inch equalizer line was installed to facilitate testing of the turbine stop valves while the plant is at 100% power. Because of new loads identified with turbine stop valve fast closure, 10 new steamline supports were added and 8 existing supports were modified. Also, hangers were modified and added to the existing bypass lines.
Summary of Saf ety Evaluation This modification does not introduce new anchor points or govern ing stress points. The new and modified hangers reduce the calcu lated pipe stresses. This modification meets applicable requirements of ASME Section III and ANSI B31.1.
Description of Change The LPCI recirc loop selection logic was modified so that the recirc pump suction valve in the selected loop does not receive a signal to close. Problems with #11 recirc pump discharge bypass valve required that the interlock be reinstalled on the suction valve and removed from the discharge and discharge bypass valves. The interlocks will be returned to the discharge valves after repairs can be made to the discharge bypass valve.
Summary of Safety Evaluation This modification assures that a break between the recirc pump isolation valves will depressurize the reactor vessel so that low pressure ECCS systems can provide core cooling. One of the recirc pump discharge valves will still close upon LPCI initiation providing the correct path of coolant to the vessel.
- 10.
CHANGES TO MONTICELLO SEGMENTED TEST ROD (STR) BUNDLE FOR CYCLE 7 OPERATION (78M0/2)
Description of Change Six irradiated segmented rods were removed from the bundle. Fresh unirradiated rods, each containing four new segments replaced the removed rods. The locations of three pairs of STR fuel rods were exchanged to satisfy the nuclear criteria for local peaking.
Summary of Safety Evaluation This modification has no significant affect on the thermal mechanical, or nuclear characteristics of the STR bundle.
The results of the safety analysis contained in GE Document NEDE 20179 are not affected.
- 11. CORE SPRAY ISOLATION VALVE BYPASS SWITCH (78MO75)
Description of Change To conform with SRI #184 (reported above),
the core spray outboard isolation valves (MD-1751 and M0-1752) control circuits were modified. Key locked bypass switches were installed to allow closure of the outboard isolation valve if a core spray pump fails to start or trips after receiving an auto initiation signal. This modification allows operation of these valves for containment isolatior purposes.
Summary of Safety Evaluation The consequences of bypass switch failure were analyzed. A failure of either of these switches would not result in system degradation beyond that previously considered in the accident analysis.