ML20213A034

Demonstration Testing of a Surveillance Robot at Browns Ferry Nuclear Plant.Analysis of Costs and Benefits

ML20213A034
Person / Time
Site:	Browns Ferry
Issue date:	03/31/1987
From:	Farnstrom K, Feltman A, Harvey H, Howard R, Llewellyn P, Jason White REMOTE TECHNOLOGY CORP.
To:	NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
References
CON-FIN-D-1558 NUREG-CR-4815, NUDOCS 8704270352
Download: ML20213A034 (82)

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NUREG/CR-4815 Demonstration Testing of a Surveillance Robot at Browns Ferry Nuclear Plant Analysis of Costs and Benefits Prepared by J. R. White, K. A. Farnstrom, H. W. Harvey, R. Howard, A. Feltman, P. Llewellyn Remote Technology Corporation (REMOTEC)

Prepared for U.S. Nuclear Regulatory Commission P PDR

NOTICE This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, or any of their employees, makes any warranty, expressed or implied, or assumes any legal liability of re-sponsibility for any third party's use, or the results of such use, of any information, apparatus, product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights.

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NUREG/CR-4815 Demonstration Testing of a Surveillance Robot at Browns Ferry Nuclear Plant Analysis of Costs and Benefits Manuscript Completed: March 1987 Date Published: March 1987 Prepared by J. R. White, K. A. Famstrom, H. W. Harvey, R. Howard*, A. Feltman', P. Uewellyn*

A. K. Roecklein, NRC Project Manager

' Browns Ferry Nuclear Plant Remote Technology Corporation (REMOTEC) 114 Union Valley Road Oak Ridge, TN 37830 Prepared for Division of Regulatory Applications Office of Nuclear Regulatory Research U.S. Nuclear Regulatory Commission Weshington, DC 20555 NRC FIN D1558

ABSTRACT This report presents the results of an NRC project to determine whether robotics equipment can be cost effective in performing surveillance and inspection work at existing nuclear power plants. A mobile surveillance robot, called SURBOT, was developed by the Remote Technology Corporation (REMOTEC) largely from commercially-available components to perform visual, sound, and radiation surveillance within rooms designated as radiologically hazardous. SURBOT is a three-wheeled vehicle capable of maneuvering through labyrinth room entries and within congested plant areas via teleoperator (joystick) or programmed (robotic) control. High-quality color video, audio, and other data are collected by an on-board computer and transmitted through a shielded tether cable to the control console where they are displayed in real-time and also videotaped.

Testing of SURBOT was conducted at the EPRI NDE Center in Charlotte, North Carolina, and by PSE&G Corporation at the Hope Creek Nuclear Power Plant.

Both organizations suggested improvements and concluded that SURBOT is a commercially-ready system that can perform useful work and reduce personnel radiation exposure. Demonstrations were also conducted for the Commonwealth Edison Company and Duke Power Company.

SURB0T was tested in the turbine building of the Browns Ferry Nuclear Plant (BFNP) by TVA personnel for a five-month period. The results showed that SURB0T obtains higher quality data and can perform more thorough surveil-lance within radiation areas than workers wearing protective clothing. Its single robotic arm was capable of performing minor operational tasks including contamination smearing. Operation of the vehicle within a room is simplified by the advanced computer graphics displayed on the control console and the time required to perform surveillance work is not excessive.

Further, SURBOT can be transferred between rooms without releasing contam-ination in the hallways using a portable enclosure. Based on these results, TVA has estimated that over 100 person-rem exposure and $100,000 operating costs can be saved annually at the BFNP using SURBOT for surveillance in 54 turbine and reactor building rooms. When considering the capital cost of equipment and a ten-year equipment lifetime, the total present worth savings at BFNP is calculated to be $1,400,000 and the total after-tax savings is $1,900,000.

TVA recommendations for improving the function, reliability, and maintain-ability have been incorporated into a production model of SURB0T which is now commercially available from REMOTEC along with other types of mobile robots and manipulators.

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CONTENTS Page ABSTRACT........................................................... iii PREFACE AND ACKNOWLEDGMENTS........................................ xi EXECUTIVE SUhMARY.................................................. 1

1. INTR 000CTION................................................... 1-1

2. DESCRIPTION OF SURB0T SYSTEM................................... 2-1 2.1 Desi gn and Operati ng Requi rements . . . . . . . . . . . . . . . . . . . . . . . . 2-1 2.2 System Arrangement....................................... 2-2 2.3 SURB9T................................................... 2-4 2.4 Co n t r ol Con s ol e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7 2.5 Cont ami nati on En cl os u re . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9 2.6 R o b o t Op e r a t i o n s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9

3. IN-PLANT TESTING............................................... 3-1 3.1 Pr el i mi n a ry Tes t i n g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 3.1.1 EP R I ND E Ce n t e r . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 3.1.2 PSE&G Hope Creek Nucl ea r Pl ant. . . . . . . . . . . . . . . . . . . 3-3 3.2 BF NP Te s t i n g Ap p r oa c h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5 3.3 Description of Test Rooms................................ 3-11 3.3.1 Steam Jet Ai r Ej ecto r Ro om . . . . . . . . . . . . . . . . . . . . . . . 3-11 3.3.2 Moi s tu re Se pa r a t o r Ro om . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12 3.3.3 Hi gh Pressure Feedwater Heater Room. . . . .. . . . . . . . . 3-17 3.3.4 Low Pressure Feedwater Haater Room. . . . . . . . . . . . . . . 3-17 3.3.5 Main Turbine Room................................ 3-19 3.3.6 Steam Packing Room............................... 3-21 3.3.7 Offgas Recombiner Room........................... 3-22 3.4 Eval uati on of SURBOT Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22 3.4.1 Vi sual Surveill ance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24 3.4.2 Audio Systems.................................... 3-24 3.4.3 SURBOT Driving Contro1........................... 3-25 3.4.4 Robotic Arm...................................... 3-25 3.4.5 Radi ol ogical / Safety Data Moni tori ng . . . . . . . . . . . . . . 3-28 3.4.6 Transport Between Rooms.......................... 3-28

4. PROJ ECTED PLANT BENEF I TS AND C0STS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 4.1 Ro om Su rv ei l l a n c e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 4.2 Ot h e r SUR 30T Ben e f i t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 4.3 Operat ional Cost Eval uati on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 4.4 Ec o n ome t r i c Mod el s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5 v

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5. COMMERCIALIZATION PLANS (PHASE 111)............................ 5-1 5.1 SU R B O T - Wh e e l e d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-1 5.2 SU R B O T - Tr a c k e d . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3 5.3 Ma i n t e n a n c e Ro b o t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4

6. CONCLUSIONS.................................................... 6-1 vi

LIST OF FIGURES Page Figure 1 SURBOT and control consol e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Figure 2 SURBOT path in separator room.......................... 4 Figure 3 SURB0T in moisture separator room...................... 4 Figure 1.1 Methodol ogy for roboti cs appl i cati on. . . . . . . . . . . . . . . . . . . 1-1 Figure 2.1 BFNP - Units 1 and 2................................... 2-1 Figure 2.2 SURBOT i n ope rati on . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3 Figure 2.3 SURBOT arm extended.................................... 2-4 Figure 2.4 SURB0T with surveillance tower partially extended...... 2-6 Figure 2.5 SURBOT i n travel confi gurati on . . . . . . . . . . . . . . . . . . . . . . . . . 2-7 Figure 2.6 SURBOT control cons ol e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8 Figure 3.1 SURBOT test course - EPRI NDE Center................... 3-2 Figure 3.2 Pl a n v i ew - B F NP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8 Figure 3.3 El ev ati on Section A- A - BFNP . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9 Figure 3.4 El evati on Secti on B-B - BFNP. . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10 Figure 3.5 Steam jet air ejector room............................. 3-11 Figure 3.6 SURBOT i n steam j et ai r ej ector room. . . . . . . . . . . . . . . . . . . 3-12 Figure 3.7 Cl ose-up vi ew of component . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13 Figure 3.8 Moisture separator room................................ 3-14 Figure 3.9 SURBOT i n moi sture separat or room. . . . . . . . . . . . . . . . . . . . . . 3-15 Figure 3.10 Moisture separator room main steam lines............... 3-15 Figure 3.11 SURBOT i nspecti ng mai n steam l i nes . . . . . . . . . . . . . . . . . . . . . 3-16 Figure 3.12 View of main steam lines at 1:1 magnification.......... 3-16 Figure 3.13 View of steam line component at 6:1 magnification...... 3-17 Figure 3.14 Hi gh pressure feedwater heater room. . . . . . . . . . . . . . . . . . . . 3-18 Figure 3.15 Low pressure feedwater heater room..................... 3-18 vii

Page Figure 3.16 SURBOT i n LP feedwater heater room. . . . . . . . . . . . . . . . . . . . . 3-19 Figure 3.17 SURBOT path i n mai n tu rbi ne room. . . . . . . . . . . . . . . . . . . . . . . 3-20 Figure 3.18 SURBOT i n mai n turbi ne room. . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21 Figure 3.19 Steam packing exhaust room............................. 3-21 Figure 3.20 SURBOT in steam packi ng exhaust room. . . . . . . . . . . . . . . . . . . 3-22 Figure 3.21 Offgas recombiner room................................. 3-23 Figure 3.22 SURBOT i n of fgas recombi ner room. . . . . . . . . . . . . . . . . . . . . . . 3-23 Figure 3.23 Robot tong gripping va1ve.............................. 3-26 Figure 3.24 SURBOT posi ti on over shiel d bl ock . . . . . . . . . . . . . . . . . . . . . . 3-27 Figure 3.25 SURBOT inserting object into shield block. . ..... . . . . . .. 3-27 Figure 3.26 Contamination smear samp11ng........................... 3-28 Figure 3.27 SURBOT in containment box and console . . . . . . . . . . . . . . . . . . 3-29 Figure 4.1 Cost comparison (3 BFNP reactors)...................... 4-7 Figure 4.2 Cost comparison (1 BFNP reactor)....................... 4-8 Figure 5.1 SU R B 0 T - wh e el ed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2 Figure 5.2 SURBOT - t racked (cou rtesy REM 0TEC) . . . . . . . . . . . . . . . . . . . . 5-4 Figure 5.3 RM-10A master control station (courtesy REM 0TEC)....... 5-5 Figure 5.4 RM-10A slave assembly with booting (courtesy REMOTEC).. 5-6 Figure 5.5 Maintenance robot...................................... 5-7 viii

l LIST OF TABLES Page Table 3.1 Surveillance room candidates for SURB0T................. 3-7 Table 4.1 Cost elements for room surveillance (per entry)......... 4-2 Table 4.2 Cost elements for BFNP room surveillance (annual)....... 4-3 Table 4.3 Operating costs for BFNP room surveillance (annual)..... 4-6 ix

PREFACE AND ACKNOWLEDGMENTS This report is the result of research performed for the United States Nuclear Regulatory Commission , Contract NRC-04-84-140, to design, construct, and perform demonstration testing of a mobile inspection robot at the Browns Ferry Nuclear Plant. The objective was to obtain operating experience and hard cost / benefit data to demonstrate that robotics can reduce occupational radiation exposure in a cost-effective manner.

The results of this project have clearly shown that the developed surveil-lance robot (SURB0T) will significantly reduce exposure and other operating costs associated with worker entry into radiation-controlled areas.

Further, the SURBOT (which is not limited by exposure or biological needs) can perform more thorough and frequent inspections than human workers and provide a permanent videotape of the results. Based on these results, the Remote Technology Corporation (REMOTEC) has designed a family of mobile surveillance and maintenance robots for commercial application within the nuclear industry and other hazardous environments.

The authors wish to thank the following individuals for their contributions to the design and testing of SURB0T and to the preparation of this report:

• K. Brittain - EPRI NDE Center

• J. B. Coughlan - REMOTEC

• H. T. Roman - PSE&G Research Corporation

• P. E. Satterlee, Jr. - Consultant

• R. G. Upton - REMOTEC

• K. L. Walker - REMOTEC

• R. H. Wiles - REMOTEC l

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l DEMONSTRATION TESTING 0F A SURVEILLANCE ROBOT AT BROWNS FERRY NUCLEAR PLANT l

ANALYSIS OF COSTS AND BENEFITS EXECUTIVE

SUMMARY

A mobile surveillance robot, called SURBOT, was developed by the Remote Technology Corporation (REMOTEC) to perform visual, sound, and radiation surveillance within rooms designated as radiologically hazardous at nuclear power plants. The design, fabrication, and assembly of SURBOT was performed in a ten-month period and was completed in June 1985. It was then subjected to twelve months of preliminary testing and design modifications prior to installation in the BFNP. During this period, SURBOT was evaluated at the NDE Center (MEAC) operated by the Electric Power Research Institute in Charlotte, NC. The tests were conducted by NDE Center personnel and involved driving SURBOT through a complex obstacle course and performing a series of surveillance tasks. An in-plant test was also performed by the Public Service Electricity and Gas (PSE&G) Company in the feedwater heater rooms at the Ibpe Creek Nuclear Plant prior to fueling for startup. Both organizations concluded that SURB0T was " plant ready" and would be capable of fulfilling surveillance missions in controlled radiation areas.

The SURB0T system consists of three major assemblies including a mobile surveillance robot (called SURBOT), a portable control console, and a portable contamination enclosure. During operation, the control console and contamination enclosure remain in the hallway and SURBOT is driven into the controlled radiation area. SURBOT is cylindrical in shape and is supported by three wheels of which two have independent drives and the other is freewheeling (Figure 1). A near zero turning radius is achieved by reversing the direction of the drive wheels. A cable reel is located within the body and automatically unwinds and rewinds cable as SURB0T moves and turns. This allows maneuvering through complex paths without having the cable become entangled on plant equipment. Forward and reverse driving cameras and lights are also located within the body.

Visual surveillance is performed by a color TV camera that is equipped with

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a motorized zoom lens and variable intensity lights. The camera is mounted on a pan / tilt mechanism along with a directional microphone capable of detecting noises from steam leaks, bearings, valves, motors, and other sources and can be raised up to 15 ft above the floor. The robot arm is provided mainly for obtaining contamination smears from the floor and equipment. It has sufficient load capacity and dexterity to perform a variety of other tasks such as opening doors, actuating valves, picking up debris, cleaning up spills, and operating power tools. The portable control console contains all of the control and data display / recording com-ponents needed to operate SURBOT. Monitors for the driving cameras are located on top of the console and the larger color monitor displays the surveillance camera picture. A video cassette recorder simultaneously records color video from the surveillance camera, audio from the direc-tional microphone, audio input from the operator, and all sensor data displayed on the main menu of the touch screen terminal.

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SURBOT was delivered to the BFNP on July 7,1986, and installed in the tur-bine building. The responsibility for testing and evaluating the system was assigned to the Radiological Control (RADCON) Group and two technicians were trained for one week as SURBOT operators at the REMOTEC facilities.

The first three weeks of in-plant testing was devoted to familiarizatior, with the equipment which included repeatedly driving it into and within most of the turbine building rooms. The object was to develop operator.

proficiency and to identify rooms which SURBOT could and could not enter.

Unrestricted access was possible as the plant was in an extended outage during this period and smearable contamination had been removed from the floor of the turbine building rooms. It was determined that SURBOT could be used in any room that had adhquate space for entry and did not require climbing over obstacles greater than one inch in height. Rooms that meet these requirements and will have moderate-to-high radiation levels during plant operation are considered candidates for remote sur.eillance with SURBOT. This led to the identification of 54 candidate rooms of which 36 are in the turbine building and 18 in the reactor building. Plant opera-tions, maintenance, security, and RADCON personnel all participated in estimating the conditions within the rooms, the entry requirements, and the specific surveillance / inspection tasks to be performed.

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SURBOT was tested successfully in each of the candidate turbine building rooms as described in this report. The most important areas for the use of SURBOT are the moisture separator rooms. They are very large,115-ft-long by 80-ft-wide by 30-ft-high, have whole body radiation exposure levels from 0.5 R/hr to 5 R/hr, and temperatures from 90*F to 130*F during power opera-tion. Testing demonstrated that SURBOT can perform a thorough inspection of the room by entering each of the labyrinth entrances and following the dotted line paths shown on Figure 2. The mobility of SURB0T within the room is limited by piping obstructions (Figure 3) and the 150-ft-long tether cable.

There are three difficult areas to inspect in the moisture separator room.

The electro-hydraulic control valves are located on a platform about 15 feet above the floor. Worker access is via a metal staircase. SURB0T was able to park alongside the platform, raise the camera up 15 feet, and check for oil leaks. The level control reservoir room is located beneath the moisture separator room with worker access via a staircase. SURBOT was able to park above the room and look down through the metal grating floor to inspect components. The grating actually disappeared from the picture with the zoom lens at high magnification. Inspection of the main steam lines from the reactor was quite successful. These lines are routed through a shielded tunnel and up into the moisture separator room. Workers use flashlights to look down into the tunnel and examine the pipes and valves for signs of leakage or malfunction. The workers' view is not good.

By using the zoom lens and spotlights, SURB0T can actually perform a close-up examination of components.

The in-plant testing verified that SURBOT is capable of replacing workers to perform remote surveillance within at least 54 rooms at the BFNP. A detailed evaluation was made of the costs associated with worker entry into these rooms as compared to SURBOT entry. The savings per year at the three-unit plant are estimated to be:

• Labor (room entry plus dress-out) = 4600 hours0.0532 days <br />1.278 hours <br />0.00761 weeks <br />0.00175 months <br />

• Protective Clothing (purchase and laundry) = 3000 sets

• Personnel Radiation Exposure = 108 rem Mathematical models that have been developed for evaluation of cost-effectiveness of engineering modifications intended for dose reductions were applied to this use of SURB0T. They showed the present worth of SURBOT over a ten-year period to be $1,460,000 without consideration of taxes and inflation. The after-tax value is calculated to be $1,930,000.

Both cases assume that SURBOT will have a useful life of ten years with annual maintenance costs equal to 5.5% of the original purchase price.

BFNP personnel expect that additional benefits will develop as SURB0T is integrated into operations and maintenance activities including:

• Worker supervision to decrease number of non-active participants within radioactive work zones.

• QA monitoring and validation to assure that maintenance procedures have been correctly followed.

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• More complete surveillance data on components during power operation.

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• Maintenance worker training and work task planning using SURBOT videotapes.

• Evaluation of surveillance data videotapes by supervision and specialists .

• Improved worker safety and decreased liability of plant operators for worker injury claims.

The in-plant tests produced a number of recommendations for improving the function, reliability, and maintenance of the prototype SURB0T system.

These have been incorporated into the design of a production model which will be produced commercially by REMOTEC as required by Phase III of the SBIR contract. In addition, the SURBOT technology will be applied to a tracked surveillance vehicle that is capable of climbing over obstacles and up/down stairs. A third robotic vehicle, also planned for commercializa-tion, involves the installation of two telerobotic manipulator arms onto the tracked vehicle for performing work tasks at nuclear power plants and other hazardous industries.

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1. INTRODUCTION The SURB0T system described in this report was developed by REMOTEC under a three-phase development project sponsored by the NRC. Phase I of the pro-ject (completed in March 1984) included a survey of currently used robotic l equipment and an analysis of three TVA nuclear plants to identify specific plant areas with a high potential for using surveillance robots (Ref.1).

The analysis included reviewing plant equipment and area arrangement drawings, assessing plant occupational radiation exposure records, and extended tours within controlled radiation areas. Discussions were held with ALARA engineers, RADCON technicians, operators, and maintenance workers. Specific information and recommendations were obtained on surveil-lance tasks where robotics would be desirable. The applications dealt with radiation exposure reduction of plant workers, worker safety, uncomfortable working conditions (high temperature and humidity), the man-hours asso-ciated with suit-up to make an inspection that requires only a few minutes of time, and the quality of inspections.

A robotics application methodology, as shown in Figure 1.1, was developed during Phase I. The methodology proceeded along two paths: one is require-ments oriented and the other is equipment oriented. The review of plant data at the TVA plants was the basis for defining the inspection and surveillance task requirements. From these requirements, candidate hard-ware items were selected from a data bank of robotic components and these REQUIREMENTS REVIEW PLANT DEFINE DATA AND INSPECTION EVALUATE USE SELECT REQUIREMENTS IN OTHER AND

• PLANT AREAS POTENTIAL AREAS LOGISTICS h

EQUIPMENT V V ESTABLISH ESTABLISH PURCHASE, DATA BANK 0F SELECT ROBOT SYSTEM ASSEMBLE, ROBOTIC COMPONENTS CONCEPT AND AND TEST ANALYZE COST

• EQUIPMENT COMP 0NENTS BENEFIT V

PLANT INSTALLATION Figure 1.1 Methodology for robotics application.

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were used to establish system concepts and to estimate costs and plant benefits. Seven specific robotic application examples were defined in the Phase I report. Of these, the system with the highest potential (a mobile surveillance robot that could be deployed within the turbine building at the BFNP) was selected by NRC for fabrication and in-plant demonstration testing in the Phase II effort.

The design, fabrication, and assembly of SURBOT was performed in a ten-month period and was completed in June 1985. Extensive testing and debugging of hardware and controls was conducted in the REMOTEC facilities for about three months. This was followed by demonstration testing at a number of power plants and the EPRI NDE Center in Charlotte, North Carolina. The objective was to obtain input from potential users regarding improvements that should be made to the design and operating features. SURBOT performed all tests well and the general reaction to it was very positive, especially with respect to its " user-friendly" control station and data recording.

Following these demonstrations and implementation of the recommended improvements, SURBOT was installed in the BFNP in July 1986 and tested by TVA personnel for five months. The results of the testing are described in this report along with improvements that have been made for the production model of SURBOT. It should be noted that Phase III of the program requires REMOTEC to commercialize the develope ( technology.

References

1. J. R. White, et. al ., " Evaluation of Robotic Inspection Systems at Nuclear Power Plants," NUREG/CR-3717, March 1984.

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2. DESCRIPTION OF SURB0T SYSTEM This section contains an overview of the basic design requirements, con-figuration, and operating features of the SURBOT system.

2.1 Design and Operating Requirements The BFNP is a three unit BWR, operated by TVA, and located in Decatur, Alabama. Unit 1 began operation in August 1974, Unit 2 in March 1975, and Unit 3 in 1977. Each unit is capable of 1067 net MWe and is equipped with independent cooling systems, turbines, generators, and control rooms. A plan view of Units 1 and 2 is shown on Figure 2.1. It can be seen that the turbine building contains a large number of shielded rooms in which the radioactive primary system piping and other components are located. During reactor operation, the temperature within the rooms ranges from 90*F to 130*F and radiation levels from 10 mR/hr to over 5 R/hr.

Worker entry to perform inspections and surveillance is required on an infrequent basis. Radiation work permits must be authorized for entries with work limitations and radiological protection measures prescribed by the RADCON Group. In most cases, full contamination zone protective clothing is required. The hallways are maintained contamination-free with step-off pads for worker undressing located at the doorway to each room.

Most inspections involve looking and listening for leaks and abnormal )

equipment operation, measuring radiation and contamination levels, checking the position of valves and indicators, and reading gauges. This can be done in some rooms by simply standing inside the doorway. However, some require the workers to walk hundreds of feet and to climb metal ladders and stairs in order to properly inspect the equipment.

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2-1

Design requirements established for a surveillance robot system that can replace human workers within the BFNP turbine building include the following.

1. Type of inspection - Better than or equal to those now performed by workers relative to coverage within the rooms and quality of data obtained.

2. Multiple use - Easily transportable between rooms that have similar configurations and surveillance requirements. Most areas cannot justify the cost of a dedicated robot system.

3. Plant modifications - Should require minimum modifications to existing plant structures and equipment for installation.

4. Power source - Use standard plant power supply sources and recep-tacles. Battery power possible if recharge time does not degrade robot use factor.

5. Signal transmission - Cabling is preferred to avoid radio-frequency interference with power plant equipment and to obtain highest quality data, i

6. Data recording - All surveillance data to be permanently recorded for review by others, for comparative evaluation with future surveillance data, and for training applications.

7 Operator control - Operator located outside room within uncon-taminated hallway where protective clothing is not required.

8. Type of control - All functions capable of teleoperated (joystick) and computer-programmed operation with remote teaching capability.

9. Environmental - Robot capable of continuous performance when sub-jected to a 120 F,100% relative humidity and 10 R/hr radiation environment.

10. Contamination control - Capable of transfer between contaminated rooms without releasing contamination into the hallways (equivalent to workers wearing protective clothing).

11. Maintenance - Capable of water spray decontamination with stan-dardized components and modular construction.

12. Reliability - Equivalent to industrial robot systems with 300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> meantime between failures (MTBF).

2.2 System Arrangement The surveillance robot system, consists of three major assemblies including the mobile surveillance robot (called SURBOT), a portable control console, and a portable contamination enclosure. Figure 2.2 illustrates the system in operation. The contamination enclosure and control console remain in 2-2

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the hallway while SURBOT is dispatched within the contaminated room to per-form surveillance. The SURBOT system is designed to inspect the shielded rooms shown in Figure 2.1. Control of the robot and its surveillance sensors is by means of the control console located outside of the hazardous environment.

The control console contains data display and recording equipment. Graphic, real-time display of the robot orientation in the room, as well as inspec-tion sensor positions, and a visual display in real-time of the inspection data is provided by the control console. These are all recorded on a stan-dard video cassette recorder (VHS) format. Control of the robot and all inspection sensors is by tethered control cable. Positioning of the robot and the inspection sensors is either pre-programmed or teleoperated.

Transferring the robot between rooms is accomplished by means of a sealed containment box to avoid spreading contamination into uncontrolled access areas. Therefore, operators do not require protective clothing to operate the robot or to transfer it to different work stations. Transfer of the robot within the containment box to a work station, as well as the transfer of the control console, can be accomplished by one worker.

The robot is capable of continuous operation in temperatures of 120*F and intermittent operation at higher temperatures. It can withstand 100%

relative humidity and be exposed to steam leaks and water spray while 2-3

maneuvering in up to 3 in. of water. All maintenance and repairs to the robot are normally done by direct worker cantact, although these operations could be performed by suited workers in a controlled area. The exterior of the robot and the containment box internals can withstand a decontamination

spray.

A number of considerations influenced the overall design in order to ensure

! industry acceptance. Foremost among these was flexibility of operations so

! that the inspection robot could be retrofitted in existing plants. This makes the robot a general-purpose inspection device and leads to another important consideration, that the inspection system provide a reasonable cost / benefit to the user. Development costs and hardware costs were mini-mized by utilizing commercially-available equipment wherever possible.

Software costs were kept at a minimum by using identical vehicle and control console computers.

2.3 SURBOT i

SLRBOT is cylindrical in shape and equipped with a variety of sensors as siown in Figure 2.3. It has an outer diameter of 31 in., a collapsed height of 55 in., and weighs approximately 600 lbs. The base module is supported by three wheels of which two drive and the other is freewheeling.

It has variable speed forward and reverse drive, can travel at speeds up to i

12 in/sec on a flat surface, and can climb 10 inclined surfaces or over l 1-in.-high obstacles. A near zero degree turning radius is achieved by l reversing the direction of the drive wheels. The base is sealed, allowing E

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2-4 t

operation in standing water up to 3 in. deep. The base module also con-tains heavy-duty rechargeable batteries that eliminate the need for large conductors in the umbilical cable.

The cable reel module is bolted to the top of the base and has a unique cable management system that automatically unwinds and rewinds cable as SURBOT moves. The motorized reel is synchronized with the base drive wheels to assure that the flexible cable is deployed onto the room floor in an untensioned manner. This allows SURBOT to maneuver through complex paths without the cable becoming entangled on surrounding equipment and permits the operator to concentrate on maneuvering SURBOT and operating the surveillance equipment without being concerned about the cable. Currently, the reel contains 150 ft. of cable. However, this can be increased to about 1000 ft. by converting to fiber optics for signal transmission.

The upper module of SURBOT contains the vehicle computer, motor amplifiers, and other electronics. Sensors attached to the top of this module include an air sampling blower, a temperature and humidity probe, a radiation probe, and a speaker for voice commands to other workers who may be in the vicinity. Two black-and-white TV cameras are provided for viewing during forward and reverse drive. These cameras have fixed, wide-angle lenses which are oriented to provide the operator with a natural perspective of the pathway being traversed. In addition, they have the unique capability to electronically adjust the view + 20 vertically without changing the camera position, enabling the operator to view the pathway from a few inches to tens of feet in front of SURBOT.

The upper module also contains the subsystem for surveillance. Visual surveillance is performed with a color TV camera equipped with a motorized zoom lens and variable intensity spotlights. The color camera system is mounted on a pan / tilt mechanism along with a super directional microphone that is capable of detecting low amplitude noises from steam leaks, bearings, valves, motors, and other sources. The pan / tilt mechanism is attached to a tower that can be extended about 15 ft. above the floor thus eliminating the need for climbing stairs within the rooms. Figure 2.4 is a photograph of SURB0T showing the surveillance tower partially extended.

The robot arm, which is an integral part of the upper module, is provided primarily to obtain contamination smears from the floor and other equipment.

It also has sufficient dexterity and a load capacity of 22 lbs to perform a variety of other tasks such as actuating valves, cleaning up spills, picking up debris, opening doors, and operating power tools. The arm has 7 degrees-of-freedom driven by electric motors. Absolute position feedback of each joint is sent to the control console. This permits the arm to be teleoperated using the master arm on the control console or robotically operated following a computer program. Figure 2.5 is a photograph of the arm position during travel of SURB0T.

2-5

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2.4 Control Console The portable control console contains all of the control, display, and data acquisition components required to operate SURBOT. With the master arm collapsed, the console is 77-in.-high by 24-in.-wide and 28-in.-deep. It is supported by four semi-pneumatic tires (two of which freely pivot) for ease of maneuvering through hallways, doors, and elevators. Figure 2.6 is a photograph of the control console.

Frequently used controls and indicators are located on the sloped panel within convenient reach of a seated or standing operator. This includes joysticks for driving the SURB0T base and directing the' pn/ tilt mechanisms for the surveillance camera, floodlights, and directional microphone.

Switches are used to control the tower drive, surveillance camera zoom / iris / focus, steering camera tilt, light intensity, air sampler, inter-com speaker, and sound analyser for the super-directional microphone. The touch screen monitor displays the distance traveled and current course heading, the base elevation of the tower, pan / tilt directions of the i surveillance camera, current time and date, and real-time output of the temperature, humidity, and radiation sensors. Also included on the touch screen display is a computer graphic map of the room undergoing surveillance and the real-time position and direction of SURBOT within the room.

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The color TV monitor located above the sloped panel displays the picture from the surveillance camera. The black-and-white monitors on top of the console are used for steering SURBOT in the forward and reverse directions and are coded to indicate the proper orientation of SURBOT. The base of the console contains a video cassette recorder (VCR), the console computer, and interfacing electronic circuitry.

The VCR simultaneously records audio signals from the directional micro-phone, color video from the surveillance camera, and all sensor data that were displayed on the touch screen. Upon completion of surveillance opera-tions, the videotape can be played back to review operations and sensor data and then stored for comparison with future inspections.

The control console also contains a 10-band, audio frequency, graphic equalizer. This permits selective frequency listening using the direc-tional microphone and allows the operator to eliminate extraneous background noise. The equalizer has an amplitude scale for each frequency allowing the operator to note intensity levels for future comparison.

2.5 Contamination Enclosure The contamination enclosure is a rectangular box used for storing and trans-porting SURBOT. It is painted for corrosion-resistance and is capable of wet spray decontamination. It is primarily intended to prevent the spread of contaminants when SURB0T is moved to different rooms. The enclosure also contains a watertight feedthru connector for the tether cable connec-tion between the control console and SURB0T.

2.6 Robot Operations SURBOT is controlled by a unique combination of teleoperation and robotics, referred to as tele-robotics technology. Total reliance on teleoperation is undesirable as the time required to perform surveillance work could be 8 to 10 times longer as compared to an unsuited worker (Ref. 1). On the l

other hand, an autonomous mobile robot would require sensors and artificial I intelligence that are beyond the current state-of-the-art. The compromise l

solution was to equip the SURBOT drive motors with position sensors such that closed-loop control is achieved. This allows SURB0T to be teleoperated through a room with the computer in a self-teach mode and brought out of the room under programmed control. The robot arm, tower, TV camera pan / tilt, and other sensor actuators are also programmable. It is possible l

to teach SURB0T to follow a specific path and perform a set of surveillance activities within a room via teleoperation and store the program on a floppy disk. At present, SURBOT automatically returns to within a few inches of its original starting point which permits pre-programmed surveil-lance if an indexed starting point is accurately established.

A major problem encountered with remotely controlling mobile vehicles within large rooms is disorientation of the operator. That is, the operator can observe the scenes transmitted from the vehicle cameras, but these do not provide a frame of reference to indicate the location of the vehicle within the room or the direction in which the cameras are aimed. The 2-9

solution used on SURBOT is to provide a graphic display of the room floor plan and the real-time position and direction of SURB0T within the room on the touch screen monitor. The path to be followed by SURBOT is shown by dashed lines, and inaccessible areas are indicated by shading. A number of points are also indicated where SURB0T must stop and raise the TV camera to inspect specific components. When maneuvering through tight areas, such as the labyrinth entry, it is possible to enlarge this area of the map and actually steer SURBOT through the labyrinth to avoid collision with the wall s . .

References

1. W. R. Hamel, et. al., "The Advancement of Remote Systems Technology:

Past Perspectives and Future Plans," in Proc. National Topical Mtg. on Robotics and Remote Handling in Hostile Environments, April 1984.

I l

2-10

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3. IN-PLANT TESTING The prototype SURBOT system described in the previous section was designed, fabricated, and assembled in a ten-month period. it was then subjected to twelve months of preliminary testing prior to installation and five months of testing in the BFNP as described in this section.

3.1 Preliminary Testing Most of the preliminary testing was performed at the REMOTEC facilities to determine performance characteristics, operability, reliability, and to make modifications that improve these features. SURBOT was demonstrated at two Health Physics Society meetings (Chicago in May 1985 and Knoxville in February 1986), at two Commonwealth Edison Company plants (Dresden and Quad Cities) in November 1985 and at the NRC Bethesda offices in December 1985.

3.1.1 EPRI NDE Center The Electric Power Research Institute tested SURBOT at the NDE Center in Charlotte, North Carolina in September and again in October 1985. The tests were performed by NDE Center personnel. Figure 3.1 shows the obstacle test course established for SURBOT. Components incorporated into the course included:

, 1. Ramps _ - The ramps were located at various positions throughout the course and ranged from 0 to 10'.

2. Grating - Several types of grating were located around the test site to add to the introduction of new obstacles for the robot to maneuver around.

3. Stages - A stage was put in place to see if the robot can l

maneuver around it. The stage consisted of a 1.0 inch step onto the horizontal first level and then a 10' incline onto the second l evel . The other side had a 10* incline onto a horizontal plane and then a 1.0-inch-high step to the floor.

4. Water _ - A tray filled with water was incorporated in the course to see if the robot could maneuver through it without any problems. Two 10' ramps were provided so that the robot could enter and exit the tray.

l l 5. Camera Checks - Sporadic checks were taken throughout the test to determine the effects that different light levels and different distances have on the visual systerr.

6. Camera Height Adjustments - Checks were made to see if the adjustment feature works properly.

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7. Arm and Camera Coordination - Temporary walls were put in place equipped with socket plugs and valve nozzles. The task consisted of turning the valve nozzle on and off and plugging a standard cord into the power socket. Also, a gauge was put in place to see if the driver's perception is good enough to set it to a pre-determined level. ,

8. " Tight Squeeze" Test - An obstacle was set up.in the path of the robot limiting the amount of space for passage. The purpose for the test was to measure the effectiveness of the computer program control and driver ability.

9. Cable Reel Test - An intricate pattern was laid'out for the robot to travel . The test was to see if the robot has any problem rewinding its tether.

10. Back Home Test - Similar to the cable reel test. Testing the ability to come back home safely.

During the first test period, it was determined that the driving lights did not provide enough illumination for safe driving and that the rubber wheels did not have adequate friction on wet surfaces to climb 10' inclines.

These deficiencies were corrected and SURBOT successfully- passed all tests during the second test period.

3.1.2 PSE8G Hope Creek Nuclear P1 ant The Public Service Electricity and Gas (PSE&G) Company tested SURBOT at the Hope Creek Nuclear Power Plant in December 1985. The tests were conducted in the feedwater heater rooms which contained no radioactive contamination since the plant was not fueled at that time. A number of personnel from PSEAG, New Jersey Institute of Technology, and the Philadelphia Electric Company witnessed the tests. Excerpts from the SURBOT test report issued by PSE8G are: 1

1. Vehicle Performance - The one day testing of SURBOT consisted of (

setting the base station up outside the feedwater heater rooms and making repeated entries into the rooms to perform various tasks.

These tasks consisted of:

e Simple maneuvering around feedwater equipment e Raising the inspection camera to read valve and pipe markings e Retrieval of small tools and objects e " Lights out" test to retrieve preplaced objects and to find an employee purposely hiding in the room.

In all cases, the robot was driven into the room (s) by the operator and returned home automatically without operator assistance. The robot made videotapes of each room entry. Both feedwater heater 3-3

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rooms are similar in design and have entrance labyrinths which SURBOT easily maneuvered through. The rooms were quite spacious, measuring on the order of 50 ft by 80 ft each.

There was a great deal of overhead piping and other equipment in the rooms, which posed a challenge to the operator in using the extendible inspection camera. Without an upward pointing camera, the operator could extend the camera into the overhead hardware and damage it. Currently, the design of the camera tilt mechanism does not allow the camera to be tilted upward while in the rest position. Either the current design should be changed, or an upward-looking camera needs to be installed.

Throughout the testing, the vehicle performed flawlessly. There was no need to " tune" or "tweek" the hardware between room entries.

It rapidly and efficiently performed each test without equipment malfunction or need of recalibration.

Although SURBOT can be preprogrammed beforehand to enter an area, in the interest of time during this one day test, this was not done. In addition, such a feat requires precise location of the robot's wheels so as to duplicate the exact starting point.

The two-way voice communication capability with the robot and its environment is very helpful . SURBOT could be used to assist workers in a controlled area or as a means of observing and communicating with personnel. Its camera can easily record the exact maintenance sequence of a task for later verification.

SURB0T had no trouble reading 1-in.-high marker numbers on pipes over 50 ft away; and on one occasion, in the darkened room with its lights on, read a small motor nameplate tag from well over 10 ft away.

At the end of testing SURBOT demonstrated its ability to climb a 15' inclined plane. The vehicle was also driven until its tether ran out and than was driven back to the base station without any problems.

2. General PSE&G Ooservations

• SURB0T is " plant ready" now. Its' instrumentation and major subsystems are commercially mature and capable of fulfilling surveillance missions in controlled radiation areas.

• The 150 ft coaxial cable tether can be extended to 600-1000 ft by converting to a fiber optic tether.

• The videotaping capability of this robot is very useful. It provides:

-- The ability to map areas visually and instrument-wise for comparison at different times.

3-4

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-- For review of tasks accomplished by a team for later evalua-4 i

tion, debriefing, and education.

-- A documentable record of the sequence of events leading up '

to or following a situation.

• The two-way audio communication between SURBOT and the control i i

console makes it possible for instructions to be given to a work crew without exposing additional personnel to a radio- l logically hazardous environment (while at the same time l

observing the work crew via the camera system to correct any problems they may be' encountering).

! e The design of the control console incorporates many user friendly graphic aids for the operator, such as: touch screen

capability, videotape _ playback, automatic sighting target for ,

the SURBOT manipulator, and a unique screen aid for driving the

< robot through and around obstructions.

I e In the event of a drive system failure', special locking pins on j

the drive wheels can be removed allowing SURBOT to be pushed to safety rather quickly and easily.

l e Since SURBOT is tethered, its power drain capability is limited by the size of its tether. Some battery power is now contained i

on-board to offset the large current requirements of the camera lights. SURBOT could be useful for some heavy-duty tasks like tool transport, moving bioshields, and other barriers if there i

was a method of adding a " heavy-duty tether" for~special tasks

! or by simply augmenting battery capacity.

e This vehicle is the most useful and commercially ready of all the vehicles PSE&G has tested or reviewed to-date.

e Reliability of the robot under a radioactive environment remains to be demonstrated.

3.2 BFNP Testing Approach The responsibility for testing and evaluating SURBOT was assigned to t'he RADCON Group at the BFNP. Prior to in-plant testing, two technicians were trained for one week as SURBOT operators at the REMOTEC facilities. During this training period, the operators performed tasks that might be encoun-tered during operational plant use. The strength of the training program was in the convenience of being able to talk directly with the developers l

of SURBOT. This line of communication resulted in a thorough understanding of SURBOT's functions and abilities. Although the familiarization period for SURBOT was short, the training program has proven to be a necessity and l 1s strongly recommended for first time operators. It was determined that with the " user friendly" controls, only a few hours of training were needed to be able to drive SURBOT through complex paths.

3-5

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SURBOT was delivered to the BFNP on July 7,1986, and installed in the turbine building. All testing was performed by BFNP personnel with REMOTEC providing consultation via telephone when necessary. The first three weeks were devoted to familiarization with the system which included repeatedly driving it into and within most of the turbine building rooms. The object was to develop operator proficiency and to identify which rooms SURBOT could and could not enter. Unrestricted access was possible as the plant was in an extended outage during this period and smearable contamination had been removed from the floor of these rooms.

It was determined that SURBOT could be used in any room that had adequate space for entry and did not require climbing over floor obstacles greater than 1.0 inch in height. Rooms that met these requirements and will have moderate-to-high radiation levels and/or worker safety concerns during plant operation are considered candidates for remote surveillance with SURBOT. This led to the identification of 54 candidate rooms as shown on Table 3.1. The rooms have been categorized into 11 areas for convenience.

Figures 3.2, 3.3, and 3.4 show the location of these rooms within the plant.

The circled numbers correspond to the area numbers of Table 3.1.

Plant operations, maintenance, security, and RADCON personnel all partici-pated in establishing the conditions, entry requirements, and specific surveillance / inspection tasks to be performed in each room. This included room walkthroughs to point out specific valves, gauges, and other com-ponents that must be inspected. The results are shown on Table 3.1 and described in the following.

e No. Rooms at BFNP - The numbers shown are the total for all three reactor units at the plant. For example, each reactor has two steam jet air ejector rooms which produces a total of six rooms.

e Average Radiation Level - The radiation levels shown are the esti-mated average continuous dose rate that will be received by a worker while in the room. It should be noted that some piping and components that must be inspected within the rooms have radiation levels that exceed 1 R/hr. However, the workers are exposed to these for only a short period of time, o Entry Frequency - The numbers shown are based upon past experiences at the plant since there is no established entry frequency for each room, e Workers Per Entry - The normal procedure is to use a team of workers to perform surveillance within a radiation-controlled room at the plant. A typical team includes three workers representing RADCON, operations, and maintenance. An exception is the moisture separator room which, because of its large size, uses a five worker team that has two extra operations personnel.

e Entry Time - This is the estimated average time that the workers will spend within the rooms performing surveillance. It does not include time for protective clothing dress-out or undressing.

3-6

Table 3.1 Surveillance room candidates for SURBOT Average Type Area No. Rooms Radiation Entry Workers Entry Protective No. Room Name at BFNP Level (1) Frequency Per Entry Time Clothing (2)

1. Steam Jet Air Ejector 6 .06 R/hr 2/ month 3 10 min. A

2. Moisture Separator 3 1.2 R/hr 1/ month 5 15 min. A

3. High Pressure Feedwater Heater 9 .06 R/hr 2/ month 3 10 min. A

4. Low Pressure Feedwater Heater 9 .06 R/hr 2/ month 3 10 min. A

5. Main Turbine Room 3 .8 R/hr 1/ month 3 15 min. A

[ 6. Steam Packing Exhaust 3 .06 R/hr 1/ month 3 10 min. .A

7. Offgas Recombiner 3 .1 R/hr 1/ month 3 10 min. A

8. Reactor Water Cleanup Heat 3 .1 R/hr 1.5/ month 3 15 min. A, B Exchanger

9. Reactor Water Cleanup Backwash 3 1.0 R/hr 1/ year 3- 10 min. A Receiver Tank

10. RHR Heat Exchanger 6 .06 R/hr 2/ month 3 10 min. A

11. Reactor Water Cleanup Pump 6 .06_R/hr 1/ month 3 10 min. A, B II)During power production (2) A = single suit with twin canisters, single cotton coverall plus 1 set plastic B = single suit with self-contained breathing apparatus for 1/2 of entries Source: TVA BFNP RADCON Group

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• Type Protective Clothinc - The rooms will be entered by workers wearing single suits anc twin . canister respirators under normal conditions. About one-half of the entries into the reactor water cleanup backwash receiver tank room and cleanup pump room will require workers to wear self-contained breathing apparatus.

3.3 Description of Test Rooms For the in-plant testing, it was decided to confine SURBOT to the uncontam-inated rooms of the turbine building which includes the first seven areas (or .36 rooms) listed on Table 3.1. A description of the SURBOT usage within these rooms is described below.

3.3.1 Steam Jet Air Ejector Room There are two steam jet air ejector rooms for each reactor unit (number 1

on Figure 3.2). The rooms have a shielded labyrinth entrance and are j approximately 10-ft-wide by 28-ft-long by 12-ft-high. The ejector jets are powered by extraction steam to pull a vacuum on the main condenser. During normal reactor operation, the whole body radiation exposure levels within

' the room vary from 0.05 R/hr to 1.5 R/hr and the room temperature varies from 80*F to 110*F. A three-worker team will enter each room every two weeks to perform routine surveillance. Radiological and safety hazards for ,

the workers include exposure to radiation and high temperatures with the potential of exposure to steam leaks and explosive gas conditions if a com-ponent fails.

The ejector is located in the center of the room and extends horizontally along the room length as shown on Figure 3.5. There are numerous inter-connecting pipes and other components attached to the ejector which presents l a somewhat congested configuration. However, the testing demonstrated that there is adequate space for SURBOT to gain access to both sides of the ejector following the dotted line paths shown on Figure 3.5. A photograph Ny:. . '.g.: .. . ....

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3-11

l of SURBOT alongside the ejector is shown on Figure 3.6. From this position, it is possible to obtain close-up views of key components and gauges by use of the TV camera zoom lens and the camera elevating mechanism (see Figure 3.7).

3.3.2 Moisture Separator Room Each reactor unit has one moisture separator room.shown &s number 2 on Figures 3.2, 3.3, and 3.5. The rooms are very large,115-ft-long by 80-ft-wide by 30-ft-high, and contain a wide variety of equipment including six moisture separators, extraction steam lines, gauges / valves, and the electro-hydraulic control (EHC) valves. Additionally, access down into the main steam line tunnel and the level control reservoir room is through the moisture separator room. During normal reactor operation, the whole body radiation exposure levels within the room vary from 0.5 R/hr to over 5 R/hr, and the room temperature varies from 90 F to 130'F. A five-worker team performs surveillance within the room every month.

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3-12

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The moisture separator room has a tee-shaped configuration with two shielded labyrinth entrance doors. Testing demonstrated that SURBOT can perform a thorough inspection of the room by entering both doors and following the paths shown on Figure 3.8. The mobility of SURBOT within the room is limited by piping obstructions (Figure 3.9).

There are three difficult areas to inspect within the moisture separator room. The EHC valves are located about 15 feet above the room floor.

Worker access is via a metal ladder and platform. SURB0T was capable of inspecting the valves for oil leaks by parking alongside the platform and elevating the TV camera. Inspecting components in the level control room is normally performed by workers who descend down a metal staircase into the room. With SURBOT, it was possible to park above the room and use the TV camera to look down through the metal grating floor and inspect the com-ponents. The grating actually disappeared from the picture with the zoom lens extended.

Inspection of the main steam lines from the reactor was quite successful.

These lines are routed through a shielded tunnel and up into the moisture separator room as illustrated on Figure 3.10. The inspection was performed with SURBOT located at the railing as shown in Figure 3.11. A view of what a worker would see in the tunnel (1:1 magnification) is shown in Figure 3.12.

By using the TV camera zoom lens and supplemental lighting, SURBOT can actually perform a close-up inspection of components (Figure 3.13). It should be noted that the actual SURBOT view is in color.

3-13

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3.3.3 High Pressure Feedwater Heater Room There are three high pressure feedwater heater rooms for each reactor unit as indicated by the number 3 on Figures 3.2 and 3.4. Each room has a l shielded labyrinth entrance and is about 15-ft-wide by 30-ft-long by l

42-ft-high. The rooms are very congested containing two high pressure heaters with associated piping and valves. Three levels of metal grating platforms, and interconnecting stairs, surround _the heaters for inspection and maintenance purposes. Whole body radiation exposure levels during reactor operation vary from 0.04 R/hr to 1.0 R/hr and room temperature from 90 F to 130 F. A three-worker team will enter each room to parform surveil-lance twice a month. The workers must climb to each of the three platform levels and observe the piping / components for leaks or other malfunctions.

Testing showed that SURBOT can easily enter the room and move albng the path indicated on Figure 3.14. Using the TV camera, it is possible to observe the entire floor for evidence of a leak. By modifying the gratings at one or more locations, it will be possible to elevate the TV camera above the first two platform levels.

3.3.4 Low Pressure Feedwater Heater Room There are three low pressure feedwater heater rooms for each reactor unit shown as number 4 on Figures 3.2 and 3.3. Each room has one shielded labyrinth entrance and is about 34-ft-wide by 28-ft-long and 30-ft-high.

3-17

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The rooms contain one low pressure heating unit with associated piping /

valves and a portion of the turbine feedwater pump steam exhaust piping.

Whole body exposure levels range from 0.04 R/hr to 1.0 R/hr and room temper-atures from 90*F to 120*F. A three-worker team will enter the room for surveillance about twice a month.

This is a spacious room that offers very little restriction to the movement of SURBOT as shown on Figure 3.15. The maintenance platform and stairs surrounding the heater are localized and allow SURBOT good visibility of essentially all piping and components (see Figure 3.16).

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3.3.5 Main Turbine Room l

Each reactor unit has one main turbine room located on the top floor of the

turbine building (number 5 on Figures 3.3 and 3.4). The rooms are quite large,115-ft-wide by 156-ft-long, and open to the turbine building roof.

They are surrounded by shield walls with a labyrinth entry located near each of the four corners. Whole body radiation exposure levels within the ,

room during reactor operation vary from 0.03 R/hr to 3.0 R/hr. A three-worker team will enter each room once a month for surveillance.

Testing demonstrated that SURBOT can perform surveillance of the main tur-bines. However, the arrangement of the high pressure turbine, three low pressure turbines, six combined intermediate valves, upper ends of the three low pressure heaters, and associated valves / piping limits the move-ment of SURBOT. It is necessary to send SURB0T into the room through at least three of the entrances, as shown on Figure 3.17, to completely inspect a turbine. A photograph of SURBOT located inside the turbine room is shown on Figure 3.18.

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3.3.6 Steam Packing Room There is one steam packing room for each reactor unit (shown as number 6 on Figure 3.2). The rooms are relatively small, 8-ft-wide by 28-ft-long by 12-ft-high, and have a single shielded labyrinth entrance. Whole body l radiation exposure levels within the room vary from 0.04 R/hr to 8.0 R/hr l and room temperatures from 90 F to 110 F. A three-worker team will enter each room about once each month to perform surveillance.

During testing, it was determined that SURBOT could enter the room to a position (Figure 3.19) that allowed visual access to most components.

Figure 3.20 is a photograph of SURBOT within the room.

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I 3.3.7 Offgas Recombiner Room

One offgas recombiner room is provided for each reactor unit (number 7 on Figure 3.2). The rooms have a single shielded labyrinth entrance and are 18-ft-wide by 28-ft-long by 12-ft-high. Whole body radiation exposure levels within the rooms during power operation varies from 0.01 R/hr to 1.0 R/hr. Surveillance entry by a three-worker team will occur about once a month.

The offgas recombiner rooms are quite congested and SURBOT was only able to enter to the positions shown on Figure 3.21 and in the photograph of Figure 3.22. With the use of the TV elevating mechanism, it was possible to observe the entire floor area and most of the major components in the room.

3.4 Evaluation of SURBOT Features I During each of the room entries described in the previous section, SURBOT

! was required to obtain safety and radiological data including visual, sound, temperature, humidity, radiation level, smear samples, and air samples. The results of these experiences plus a few extra tests that were performed are described in the following.

I 3-22

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3-23

3.4.1 Visual Surveillance The color TV camera used for visual surveillance is equipped with a motor-ized 6:1 zoom lens and has motorized focus and iris controls. It is mounted on a pan / tilt mechanism that has + 180' pan motion and can be tilted up 90 and down about 80'. Two v 61able intensity spotlights are also attached to the pan / tilt unit which is mounted on top of an elevating mechanism called a tower. When SURBOT is moving, the tower must be collapsed to avoid collision damage of the camera with pipes or other obstructions. When SURBOT is stopped, the tower can be elevated to posi-tion the camera up to 15 ft above the floor.

Raising and lowering the tower at the control console is via a three-position switch. There is a graphic and digital display showing the camera elevation above the floor. Graphic and digital displays are also used on the console to show the pan and tilt orientation of the camera. The pan / tilt can be manually operated by a joystick controller or by pre-programmed sub-menus on the touch screen controller. For example, there are commands which direct the camera to automatically look straight up, front level, rear level, etc. A rheostat switch is used to turn on and adjust the intensity of the spotlights.

Testing of the visual surveillance equipment verified that the remote controllability is very good because of the position feedback displays and the automated sub-routines. The ability to raise the camera 15 ft above the floor proved useful in that it could, in effect, look around obstacles.

Also, in areas such as the moisture separator room, this feature eliminated the need for SURBOT to climb steps to inspect the EHC valves.

The color quality and resolution of the picture received on the monitor was excellent when viewing components 15 to 30 ft away at maximum magnification, even in totally dark areas. It is quite easy to identify discoloration caused by leakage and to read nameplate information. However, improvements in picture quality are needed for performing general, low-magnification viewing in darkened areas.

3.4.2 Audio Systems A directional microphone is attached to the color surveillance camera in SURBOT. The main objective is to zero the camera onto steam or air leaks and abnormal noise from bearings, motors, and other moving equipment. To test this feature, a tape-recorded noise was placed in a room with its j location unknown to the operator. SURBOT was then driven in and, within a few minutes, the operator was able to accurately locate the source of noise.

The task was repeated with the room lights out to simulate steam leaks, smoke, or other conditions that would render visual systems inoperative.

Without the use of the TV camera, it was more difficult to pinpoint the noise source because of sound reflection off the concrete walls, tanks, and piping. After several tests, it was determined that the sensitivity to locate sound sources (without a camera) was within + 35*.

3-24

A speaker is mounted on top of SURBOT and is connected to a microphone at the operator console. It allows the operator to converse with people in the vicinity of SURBOT and to listen to their response through the direc-tional microphone. This two-way communication link proved very useful during the in-plant testing. In a simulated maintenance operation, the operator was able to converse with workers that were located 25 ft away from SURBOT. This feature will allow operations and supervision personnel to safely oversee maintenance tasks and, with the ability to record (audio and video) this information, it can be used for quality verification and training purposes.

3.4.3 SURBOT Driving Control SURBOT is a three-wheeled vehicle with one freely pivoting wheel and the other two driven by separate drive motors. The driven wheels have forward and reverse movement which allows SURBOT to pivot almost on its centerline.

A joystick controller on the console is used to operate the drive wheels.

Two dedicated driving cameras with lights are installed in the SURB0T housing with one facing forward and one reverse. They are connected to monitors in the control console. Calibrated guide lines and distance marks on the monitor inform the operator of the clearances between the SURB0T body and obstacles.

The touch screen controller has graphic displays of the real-time path followed by SURBOT, current course direction, and a digital display of distance traveled. Sub-menus are provided to permit the operator to drive SURBOT through a room using the joystick and then return automatically under computer control. The on-board cable reel is computer controlled to

' unwind and rewind cable as SURBOT moves such that the cable is not dragged on the floor to become entangled with plant equipment.

The test results showed that SURBOT can easily be driven through labyrinth entrances and within congested rooms without contacting walls or equipment.

The operator interface is very " user friendly" and makes the driving of SURBOT into a type of computer game. The driving lights have a marginal intensity when operating in a totally darkened area. Automatic retrieval was useful in rooms where SURBOT traveled long distances and was capable of returning the vehicle to within a few inches of the start point. The auto-matic cable reel function 3d reliably throughout the testing and is con-sidered an extremely valuable feature of SURB0T. It allows the operator to concentrate on driving and surveillance without concern for the cabling.

3.4.4 Robotic Arm A seven degree-of-freedom arm is mounted on top of the SURBOT body. It can be operated manually by a master arm at the control console or robotically using pre-programmed sub-routines that are initiated via the touch screen controller. A graphic display of the real-time position of the arm is also provided at the control console.

Tests were performed to evaluate the type of tasks that could be performed with the arm and the ease of controlling the arm. During the preliminary testing of SURBOT and operator training, the arm was used routinely to turn 3-25

i door knobs, open doors, turn on light switches, open/close valves, vacuum floors, pick up objects from the floor, and other tasks. These were all performed without difficulty after a few hours of training. The use of pre-programmed sub-routines significantly reduced the time required to per-

form tasks. For example, an object could be picked-up from the floor in 6

about 30 seconds.

l In the plant, there was no problem in maneuvering SURBOT such that the tong could grip valve handles (see Figure 3.23). However, in some cases, the valves had not been operated for years. and the arm had insufficient torque to break them free. Shutting down a plant system by depressing a control panel pushbutton was easily accomplished. Retrieval of a simulated high radiation object and placing it into a lead block was also performed as shown in Figures 3.24 and 3.25. A test was also made to determine if SURBOT could maneuver thrcugh the labyrinth entrance with the arm partially extended and the tong carrying an object such as a bucket. The test was successful, however, it did require the use of a skilled driver, i

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The primary function of the robotic arm is to obtain 100 sq. centimeter contamination smear samoles from floors. To do this, a six position smear holder is inserted into the tongs before SURBOT enters the room. When SURBOT has reached the location for smearing, the arm is automatically lowered to place the smear pad in contact with the floor and the vehicle is moved forward and back (Figure 3.26). The smear holder is then automati-cally raised and rotated to the next position. This operation was completed without difficulty.

3-26

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3-27

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3.4.5 Radiological / Safety Data Monitoring In addition to the smear sampling capability, SURB0T is equipped with real- i time measurement of radiation, temperature, and humidity levels to which it '

is exposed. This data is continuously displayed to the operator in digital form and is also recorded on the videotape. When combined with the real-time position of SURBOT within the room, it is possible to prepare radiation maps without actually entering the room. SURBOT was also used to obtain some contact and 18-in. radiation exposure rates. This was accomplished by placing a dose rate meter in the robotic arm tong and using the surveillance camera to read the instrument output. This approach can also be used for calibration of the SURBOT radiation monitoring probe.

Air sampling is performed by a sampling blower / filter mounted on top of SURBOT. This unit is equivalent to that now used by RADCON technicians.

Removal of the filter is done manually after SURBOT has been withdrawn from the room and was judged to be acceptable.

3.4.6 Transport Between Rooms SURBOT is transported from one room to another in a containment box to pre-vent contaminating the aisle. The control console must also be moved, however, it always remains in the uncontaminated aisle. Both of these are shown on Figure 3.27. The procedure is to place the console within 25 ft 3-28

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of the room entrance and connect the cable to a standard 110 VAC power outlet. The containment box is positioned in front of the room entrance, the door opened, and the ramp lowered onto the step-off pad after which SURBOT can be driven into the room.

Movement of the containment box and console is easily accomplished by one worker. However, the wheels on the hand truck, used to move the contain-ment box, have a small diameter and make it difficult to cross gratings and onto elevators. Also, the large size of the containment box door required the box to be set down further ir.*.o the aisle than is desired.

i 3-29

4. PROJECTED PLANT BENEFITS AND COSTS The previous section has described the in-plant operating experience obtained with the prototype SURBOT. Based on this, projections of the quantitative and qualitative plant benefits and costs expected to be realized at the BFNP have been made and are described in this section.

4.1 Room Surveillance The in-plant testing verified that SURBOT is capable of performing remote surveillance within a total of 54 rooms at the BFNP as listed on Table 3.1.

The data compiled relative to background radiation level, frequency of entry, workers per entry, time of entry, and type of protective clothing required is based upon ten years operation of the BFNP.

Cost elements for worker entry into the rooms consist primarily of the man-hours required for suiting up/unsuiting and to perform the surveillance task, laundering or replacement of protective clothing, and the radiation exposure received. When using SURBOT, only the man-hours required for setup and performing the surveillance are considered since no protective clothing or exposure to radiation is involved. A projection of these elements is listed on Table 4.1 for each entry into the eleven different types of rooms. The man-hours are based upon time-measured performance runs of the actual tasks. Extrapolation of the individual room entry cost elements to a 12-month (annual) basis is listed on Table 4.2.

4.2 Other SURBOT Benefits The benefits shown on Table 4.2 using SURBOT to perform room surveillance at the BFNP are significant. However, plant personnel project that there are additional benefits that could be substantially higher. It is however, difficult to predict exact values for these benefits which include the following.

1. Worker Supervision - There are a wide variety of scheduled and unscheduled maintenance tasks that must be performed in the rooms that SURBOT can enter. The worker team normally includes a fore-man or other supervisor, a RADCON technician, craftsmen, and an inspector or engineering representative. It is anticipated that the mobility of SURBOT, combined with close-up TV viewing and two-way communication between the workers and control console will decrease the number of non-active participants actually required to be in the radioactive work zones. The magnitude of the savings cannot be estimated until BFNP is on-line and SURBOT has been accepted as a part of the worker team.

2. QA Monitoring and Validation - Independent verification of main-tenance and surveillance activities on systems "important to safety", as required by the NRC's Office of Inspection and Enforcement, is occasionally difficult to prove and has resulted in plant shutdowns and fines being imposed on the utilities. It is expected that SURBOT videotapes containing verbal comments of an inspector will provide additional assurance that repair 4-1

Table 4.1 Cost elements for room surveillance (per entry)

Worker Entry SURBOT Entry Room Name Suitup(1) Clothing Inspect Rad Dose Setup Inspect (man-hr) (man-hr) (rem) (man-hr) (man-hr)

1. Steam Jet Air F,jector 4.5 3-Type A 0.5 0.03 0.75 0.3

2. Moisture Separator 7.5 5-Type A 1.25 1.5 0.75 3.0

3. High Pressure Feedwater tbater 4.5 3-Type A 0.5 0.03- 0.75 0.5

4. Low Pressure Feedwater Heater 4.5 3-Type A 0.5 0.03 0.75 0.5

5. Main Turbine Room 4.5 3-Type A 0.75 0.6 1.0 1.5

6. Steam Packing Exhaust 4.5 3-Type A 0.5 0.03 0.75 0.5

7. Offgas Recombiner 4.5 3-Type A 0.5 0.05 0.75 0.5

8. Reactor Water Cleanup Heat 4.5 1.5-Type A 0.75 0.07 1.0 1.0 Exchanger 1.5-Type B

9. Reactor Water Cleanup Backwash 4.5 3-Type A 0.5 0.5 1.0 0.5 Receiver Tank

10. RHR Heat Exchanger 4.5 3-Type A 0.5 0.03 1.0 0.7

11. Reactor Water Cleanup Pump 4.5 1.5-Type A 0.5 0.03 1.0 0.5 1.5-Type B (1) Assumes I hour for complete suitup and 30 minutes for unsuiting per worker Source: TVA BFNP RADCON Group

_ = _. _ _ _ _

Table 4.2 Cost elements for BFNP room surveillance (annual)

Entries Worker Entry SURBOT Entry Room Name Per/Yr Man-Hrs Suit A Suit B Rem Man-Hrs

1. Steam Jet Air F,jector 144 720 432 4.3 151-

2. Moisture Separator 36 315 180 54.0 135

3. High Pressure Feedwater 216 1,080 648 6.5 270 Heater

4. Low Pressure Feedwater 216 1,080 648 6.5 270 Heater

5. Main Turbine Room 36 190 108 21.6 90

6. Steam Packing Exhaust 36 180 108 1.1 45

7. Offgas Recombiner 36 180 108 1.8 45

8. Reactor Water Cleanup 54 284 81 81 4.1 108 Heat Exchanger

9. Reactor Water Cleanup 3 15 3 1.5 5 Backwash Receiver Tank

10. RHR Heat Exchanger 144 720 432 4.3 245

11. Reactor Water Cleanup 72 360 108 108 2.4 108 Pump Totals 993 5,124 2,856 189 108.1 1,472 Source: TVA BFNP RADCON Group I

procedures have been followed and that equipment valves and switches have been correctly aligned so that functional testing can be done without compromising plant safety. Specific benefits anticipated include reduction of radiation exposure and in the man-hours required to prepare validation documentation.

3. Surveillance Data - The BFNP rooms considered in the report have a moderate-to-high background radiation level with temperatures ranging from 90*F to 130 F during power operation which limit the time workers can spend performing surveillance. In some cases, the workers are required to wear respirators and face masks which obscures vision. The function of SURBOT is unaffected by these conditions, and it can remain in a room for extended periods to perform a far more thorough surveillance. Additionally, the ability of the TV camera to extend 15 ft above the floor and to zoom-in on components with floodlights provides data that cannot be obtained by workers. The monetary value of this benefit is difficult to quantify.

4. Training - Over a period of time, it is expected that an archive of SURBOT videotapes of both surveillance and maintenance tasks -

will be compiled. These tapes will be valuable in training new personnel and in planning of work tasks to decrease the time required and the exposure received when the task must be repeated.

The tapes should also prove useful in planning for equipment design modifications.

5. Evaluation of Surveillance Data _ - As mentioned previously, workers are encumbered by protective clothing, uncomfortable temperatures, poor lighting, and the pressure to perform surveillance quickly to minimize radiation exposure. Yet, they must not only inspect equipment components for evidence of malfunction, but make judg-ments as to whether any malfunctions are evident. With SURBOT, the operator is located in relative comfort outside of the controlled radiation room and has a primary objective of obtaining data. The evaluation of the data can be performed by personnel with the appropriate qualifications at another time and place.

6. Safety and Liability - It is well established that workers wearing protective clothing and respirators combined with the effects of high temperature result in a high stress situation. Further, the limited vision, extra weight, restricted communication, and mobility restrictions caused by the protective clothing increases the possibility of worker accidents. An additional concern is the rapid increase in the number of radiation injury claims made by workers since the Three Mile Island accident. While the use of .

SURBOT at BFNP will not eliminate the need for workers to wear protective clothing and enter radiation areas, it is a step in the direction of improved safety and decreased liability. J 4

4-4 i

t.

4.3 Operational Cost Evaluation The monetary value of the cost elements used for estimating the. annual operating cost to perform surveillance in the 54 BFNP rooms discussed in l this report has been established by TVA as follows:

e RADCON Technician and Operators = $18/hr .'

e Radiation Exposure = $1,000/ man-rem e Protective Clothing - Type A = $10/ suit e Protective Clothing - Type B = $27/ suit Applying these values to the cost elements of Table 4.2 results in the annual costs shown on Table 4.3. It is interesting to note that TVA currently spends about $234,000 per year to send workers into-the listed rooms for infrequent surveillance during power operation. Of this amount, 45% is for radiation exposure,15% for protective clothing, and 40% for labor. Also, over 50% of these costs result from entries into the moisture separator, high pressure feedwater heater, and low pressure feedwater heater rooms.

The costs that must be considered in the use of SURBOT to perform surveil-lance in the 54 rooms are as follows:

o Purchase of SURBOT System = $160,000 e Cost to Install = $0 e Exposure to Install = $0 e Labor to Operate = $26,500/yr e Maintenance Cost = $8,500/yr e Useful SURBOT Life = 10 years The projected annual operating costs for performing surveillance with worker and SURBOT entry over a 10 year period at the three BFNP reactor units is shown graphically on Figure 4.1. The estimate assumes a 10 year straightline depreciation for SURBOT and does not consider inflation, interest, or taxes. The total operating cost over 10 years using worker l entry is $2,340,000 and $350,000 using SURBOT. This reflects a net savings of about $2,000,000 in 1986 dollars. The break-even point will occur within the first year of operation.

Extrapolating these costs to a single reactor plant (equivalent to the BFNP) results in the operating cost comparison shown on Figure 4.2. In this case, the total operating cost over 10 years using worker entry is $800,000 and $330,000 with SURBOT. The break-even point would occur at the 21/2 year point.

4.4 Econometric Models Five mathematical models have been developed for evaluation of cost-effectiveness of engineering modifications intended for dose reductions

( Re f. 1) . Two of these models are applied to the SURBOT as follows.

4-5

Table 4.3 Operating costs for BFNP room surveillance (annual)

Worker Entry SURBOT Entry Room Name Labor Suits Exposure Total Labor

1. Steam Jet Air Ejector $12,960 $ 4,320 $ 4,300 $ 21,580 $ 2,718

2. Moisture Separator $ 5,670 $ 1,800 $ 54,000 $ 61,470 $ 2,430

3. High Pressure Feedwater Heater $19,440 $ 6,480 $ 6,500 $ 32,420 $ 4,860

4. Low Pressure Feedwater Heater $19,440 $ 6,480 $ 6,500 $ 32,420 $ 4,860

5. Main Turbine Room $ 3,420 $ 1,080 $ 21,600 $ 26,100 $ 1,620

6. Steam Packing Exhaust 5 3,240 $ 1,080 $ 1,100 $ 5,420 $ 810 p

7. Offgas Recombiner $ 3,240 $ 1,080 $ 1,800 $ 6,120 $ 810

8. Reactor Water Cleanup Heat 5 5,112 $ 3,000 $ 4,100 $ 12,212 $ 1,944 Exchanger

9. Reactor Water Cleanup Backwash $ 270 $ 30 $ 1,500 $. 1,800 $ 90 Receiver Tank

10. RHR Heat Exchanger $12,960 $ 4,320 $ 4,300 $ 21,580 $ 4,410

11. Reactor Water Cleanup Pump $ 6,480 $ 4,000 $ 2,400 $ 12,880 $ 1,944 Totals $92,232 $33,670 $108,100 $ 234,002 $26,496

COST 2000K, ,

I I

1500K_ _ WORKER ENTRY l

i 1000K TOTAL

- - l SAVINGS

$1600K l SURBOT ENTRY l i

500K_ _

l i

I I I I I I I I I I i 1 2 3 4 5 6 7 8 9 10 YEARS l

Figure 4.1 Cost comparison (3 BFNP reactors).

4-7

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COST 700K_ ,

I 600K_ ,

WORKER ENTRY TOTAL SAVINGS l OK 400K_ _ l I

300K_ _

I 200K_ _ g i

SURBOT ENTRY 4 100K_ _ g I

I I I I I I I l l l 1 2 3 4 5 6 7 8 9 10 YEARS Figure 4.2 Cost comparison (1 BFNP reactor).

I 4-8

1. Discounted REM Present-Worth Model_ - In this model, all future operating costs are converted to equivalent worth in 1986 dollars using a discount rate which reflects the real value of money (inflation and taxes are neglected). Also, since the value of a man-rem in nuclear power plant operation is usually governed by costs of manpower replacement, training, and other factors (rather than health effects costs which are usually much slower), the future man-rem savings are discounted at the same rate as used for operational savings. The equation for this model is:

Present Worth (dollars / man-rem) = F (C - A0 2)

K022-Og where: K 2 " { l + d)" ~ l d (1 + d)"

F = (1 + 1) and: F is inflation factor (to convert to current dollars)

C is capital cost of equipment A0 is sum of annual savings due to sum of labor, material, training, maintenance, overhead, waste disposal, and replace-ment power costs n is number of years over which equipment is amortized and annual savings will be summed D is dose to install (man-rem)

D is annual dose savings in man-rems per year 2

I is assumed inflation rate between base year and current year Y is number of years between base year and current yea'r I

K2 is annuity factor representing present value of payments of one dollar per year for n years d is a discount rate assumed to be 4% for this analysis Example: Consider the application of SURBOT to only surveillance within the 54 BFNP rooms listed on Table 4.3. Capital cost of the equipment is $160,000 in 1986. Since 1986 is both the base year and the current year, the inflation factor F is equal to one.

4-9

-1 Annual Operating Savings Ao. 1 i

• Labor savings = $65,700/yr

• Protective clothing savings = $33,700/yr

• Maintenance (cost) = -$ 8,500/yr Ao = Total = $90,900/yr The amortization period (n) for SURBOT is 10 years, Dy =0 D2 = 108 man-rems /yr, and d = 4%.

K = (1 + '04)l0 ~ 1 = 8.14/yr 2

.04 (1 + .04)10 j l

Present Worth = 1 ($160,000 - $90,900 x 8.14) . -$ 80 0

= ~ -$660/ man-rem (8.14 x 108 - 0)

At $1,000 per man-rem, the total present worth dollars saved over 10 years with the use of SURBOT in the 54 rooms is $580,000 +

. $1,000/ rem x 880 rems or about $1,460,000.

2. After-Tax Revenue Model - A model that reflects the revenue t

requirements based on effective (after-tax) interest rates is also of some interest. This approach reflects the Board of Director's

! or treasurer's point of view. It converts the present worth i (calculated above) to uniform annualized payments, which can be secured for n years from a present investment, using " effective" interest rate 1, which reflects tax deductions on interest payments and annuity factors K . In addition, taxes on revenues, which typically average 5% perl year, are accounted for by the factor 0.95 in the denominator of the following equations used for i this model .

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After-Tax Revenue (dollars / man-rem) = " K1 2^t}

0.95(n 2D -D) g I

K (yr~1) = 1(1 + i)"

(1 + 1)" - 1

where A is the annual operating savings, A above, less the annual federal and state taxes on capital iRyestments (assumed to be 2% of capital costs) and i is the effective interest rate (assumed to be 10%). For this model, d is assumed to be the same i

as used in the present worth model (4%).

Exam )le_: Consider again the use of SURBOT for surveillance in the 54 B:NP rooms described in Table 4.3.

l 4-10

K = 0.1(1 + 0.1)10 = .26 = 0.16 yr-I (1 + 0.1)10 -1 K = 8.14/yr (as above) 2 A, = $90,900 A = A, - 0.02 x A, = $90,900 - $1,818 = $89,100/yr After-Tax Revenue = 10 x .16 x 1.0 (','60,000 - 8.14 x $89,100) $.904,000 1026 rem 0.95(10 x 108 - 0)

= ~ -$880/ man-rem At $1,000 per man-rem, the total after-tax dollars saved over 10 years with the use of SURBOT is $904,000 + $1,000 x 1026 man-rem = $1,930,000.

References

1. Baum, J. W. and G. R. Matthews, " Compendium of Cost-Effectiveness Evaluations for Dose Reduction at Nuclear Power Plants," NUREG/CR-4373, December 1985.

4-11 J

5. COMMERCIALIZATION PLANS (PHASE III)

The in-plant tests confirm that SURB0T can be effectively installed and operated at existing plants and that the surveillance data obtained has a higher quality as compared to worker entry in radiologically-controlled rooms. Further, plant personnel accept the use of SURBOT and project that it will significantly reduce personnel radiation exposure and operating costs at the Browns Ferry Plant. Based on this and confidence that similar results will be achieved at other nuclear plants, REMOTEC plans to approach the Phase III commercialization of this SBIR contract in the following manner.

5.1 SURBOT - Wheeled _

There are significant advantages in using mobile surveillance vehicles with wheels as compared to tracked vehicles in plant areas where there are few obstacles to climb such as the BFNP. They include more accurate posi-tioning and cable handling (the wheels do not slip during a turn), less damage to floor surfaces, easier to decontaminate, easier to maintain, and less expensive.

REMOTEC has designed and is currently fabricating the production model of a wheeled SURBOT that incorporates most of the improvements suggested during the preliminary and in-plant testing. The most significant of these are as follows:

• Reduce overall size and weight of SURBOT and contamination enclosure

• Provide more floor clearance under SURB0T i

• Increase speed and torque of drive wheels 4

• Make cable and reel easily removable for decontamination

• Improve quality of color TV camera during general low-magnification viewing e Improve access to internal motors and electrical components for j ease of repair / replacement e Use larger wheels on containment enclosure e Revise door / ramp on enclosure to minimize space required in hallway

• Install security cover on console Figure 5.1 contains an isometric view of the wheeled SURBOT production It is rectangular in shape with external dimensions of 28-in.-wide

! model.

l by 30-in.-long and 46-in.-high with the elevating tower collapsed.

l A three-wheeled support and drive is used similar to the prototype except that the drive wheels are larger in diameter and road clearance increased to 3 in.

5-1

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Figure 5.1 SURB0T - wheeled.

The cable reel has been relocated on the back of the housing with the cable discharged towards the floor. Removal of the cable or the entire reel assembly can be accomplished in a few minutes as compared to hours on the prototype. The cable unwind / rewind is automatically controlled by the computer based on the movement of the two vehicle drive wheels. The cable has a urethane jacket that is watertight and can be positively driven even i when covered with water or oil.

The surveillance camera assembly has been redesigned to reduce its size and permit raising into more congested areas. A specially designed pan / tilt unit is used to permit the collision ring to always remain in a horizontal position. This assures that the camera can be moved throughout the + 180' t

pan and + 90' tilt motions safely. The elevating tower assembly is similar j to the p'rototype and is capable of raising the camera and microphone 15 feet ,

above the floor. The color TV camera and 6:1 zoom lens are contained l within a splashproof housing. A newly developed color camera and lights are used to provide high resolution output during both general and high-magnification viewing.

5-2

The prototype SURBOT used a versatile 7 degrees-of-freedom, robotic-manipulator arm that was capable of performing a variety of work tasks.

However, the in-plant testing showed that it would have limited use pri-marily to obtain contamination smears from room floors. To reduce the overall system costs, the manipulator arm has been replaced with a two degree-of-freedom smear positioning arm. The smear sample holder is the same as used on the prototype.

One of the most significant improvements is in the maintainability of SURBOT. The body is made of smooth stainless steel with a minimum of cre-

! vices to improve decontamination. Large hinged doors are installed on both sides of the body which provide easy access to internal components. The doors are gasketed to be splashproof and are secured with quick-access rotary clamps. All motors, position sensors, cameras, circuit boards, and other components that might fail have quick release electrical connectors and can be replaced in a few minutes of time.

The control console has been modified to lower the two driving camera moni-tors to a more comfortable eye level position. The master manipulator arm has been removed and a hinged lockable cover installed over the front face

, of the console. It should be noted that there is a key lock on the contain-ment enclosure and also on the rear access door of the console. Hence, the SURBOT system can be left in an unsecured area with minimal concern for tampering.

The containment enclosure is constructed of welded stainless steel for ease of decontamination. It is significantly smaller in size and weight in com-

! parison to the prototype. The 6-in.-diameter wheels attached to the enclo-sure permit easy pushing over rough floors and into elevators. An external lever is provided for lowering / raising of the ramp.

l 5.2 SURBOT - Tracked Pressurized water reactors (PWR) have numerous controlled radiation areas ,

in which a mobile surveillance robot could be effectively used. However, many of these rooms have floor obstructions, such as dikes and pipes, that preclude the use of a wheeled vehicle. Additionally, there is a need to negotiate stairs to reach some of the inspection areas.

For this case, REM 0TEC has applied the SURBOT technology and equipment com-ponents to a commercially purchased, tracked vehicle as shown on Figure 5.2.

It is a rugged, all-terrain vehicle capable of climbing stairs and over obstacles up to 20-in.-high. The vehicle is small, 28-in.-wide by 40-in.-long with the front / rear tracks raised and can operate in standing water.

l Converting the chassis to a SURBOT system involved the addition of an auto- '

matic take-up cable reel, the color TV camera with pan / tilt and elevating mechanisms, driving cameras, a contamination smear arm, and a waterproof housing. The housing is similar to that used on the wheeled SURB0T with hinged doors that provide easy access to internal components. The control console is identical for both types except for software differences.

5-3

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l 5.3 Maintenance Robot 1 During the course of this project, a number of plant personnel inquired as l to whether the REMOTEC two-armed, robotic-manipulator system could be installed on a robotic vehicle and used to perform remote maintenance work within high radiation areas. This manipulator system is called the RM-10A and is shown in Figures 5.3 and 5.4. It is normally attached to an over-

head transporter and operated in an elbows-down position by most users.

An evaluation was made to determine whether the RM-10A could be installed on the previously described tracked base. The results were positive with j regard to the overall size, capacity, and reach of the manipulator arms.

However, it will be necessary to mount the arms on the vehicle in an

elbows-up position to perform work effectively (and reach the floor) as i shown in Figure 5.5.

i

! To verify the credibility of this approach, REMOTEC has purchased a tracked i

~

vehicle on which an RM-10A manipulator system will be installed. Other features / components developed for SURBOT will.also be incorporated j including the automatic cable reel and vehicle navigation / control system.

1 Demonstration testing will be performed for the utilities to determine I whether a mobile maintenance robot vehicle has application in nuclear power

plants.

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Figure 5.3 RM-10A master control station (courtesy REMOTEC).

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Figure 5.4 RM-10A slave assenbty with booting (courtesy REMOTEC).

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6-7

6. CONCLUSIONS The primary objective of this NRC project was to obtain operating experience and hard cost / benefit data to demonstrate that robotics equipment can be used to perform surveillance / inspection work at existing nuclear power plants and reduce radiation exposure to workers and plant operating costs.

This was accomplished by developing a mobile surveillance robot (SURBOT) capable of replacing workers in performing visual, audio, and radiation surveillance within radiologically-controlled rooms. The SURBOT was tested at the EPRI-NDE Center and demonstrated at a number of power plants.

Extensive in-plant tests were performed at the Browns Ferry Nuclear Plant.

The results of this project lead to the following conclusions.

1. Mobile surveillance robots can be utilized at existing nuclear power plants without requiring plant modification or additional radiation exposure to workers for the installation.

2. The quality and quantity of surveillance data obtained with robots is improved because they are able to stay longer within radiation areas and have superior sensor systems as compared to workers wearing protective clothing.

3. Parmanent records of surveillance data can be obtained with robots for subsequent evaluation by others, to verify adherence to quality requirements, and for training purposes.

4 Plant workers readily accept the use of surveillance robots because they decrease the need to dress-out and enter controlled radiation areas and their jobs are not directly threatened.

5. Mobile robots can be used in and transferred between controlled radiation plant areas without releasing contamination into clean areas.

6. TVA projects that the use of SURBOT at the BFNP to perform surveil-lance within 36 turbine building and 18 reactor building rooms will result in an annual operating cost savings of:

e Labor = $ 66,000 e Protective Clothing = $ 34,000 e Radiation Exposure = $108,000 When considering the purchase, maintenance, and labor costs of SURBOT, the after-tax savings for a 10 year period is calculated to be $1,930,000 in 1986 dollars.

7. BFNP personnel expect that the use of SURBOT will be expanded to include replacement of supervisory personnel in radiation areas, documenting the performance of maintenance work, and other tasks.

I 6-1

8. The demonstration tests produced a number of recommendations for improving the function, reliability, and maintenance of the proto-type SURBOT system. These have been incorporated into the design of production model robots which are now cortaercially available from REMOTEC as required by Phase III of the project. Included are a wheeled surveillance robot, a tracked vehicle surveillance robot, and a maintenance robot consisting of a tracked base with two robotic-manipulator arms.

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Browns Fe\ rry ion Nuclear Testing of a Analysis Plant: Surveillance Robotand of Costs at *'""""***"" /

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x G $ $ A,1rnMs.eG ORG.Ni,.YsON N.wt .N. M.atlNG .Cong.s ,seesse /.a ceae, Rsmote Technology dorporation (REM 0TEC) 114 Union Valley Road io = uun oak Ridge, TN 37830 \ D1558

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Washington, DC 20555

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This report presents the results of an\NRC prpject to determine whether robotics equipment can be cost effective in performing surveiliance j and inspection work at existing nuclear power plants. A mobile surveillance roho , called SURBOT, was developed by the Remote Technology Corporation (REMOTEC) to perfo)m r visual, sound, and radiation surveillance within rooms designated as radiologica 'y\hazardous.

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SURBOT was tested in the turbine bui) ing of \the Browns Ferry Nuclear Plant (BFNP) by T/A personnel for a five-month period. he results showed that SURBOT obtains higher quality data and can perform more thorough [surveillanch within radiation areas than wor protective clothing. SURBOT carybe transferred'between rooms without releasing contamina-tion in the hallways using a ppetable enclosure. \TVA has estimated that over 100 person-rem exposure and $100,000 op ating costs can be saved annually at the BFNP using SURBOT for surveillance in 54 turb) e and reactor building ooms.

TVA recommendations for jmproving the function, reliability, and maintainability have been incorporated into a production model of SURBOT which is now commercially available from REMOTEC along with otb6r types of mobile robots and man't ulators.

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