ML13353A174

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Uftr Responses to Request for Additional Information (ML113560528)
ML13353A174
Person / Time
Site: 05000083
Issue date: 12/12/2013
From: Shea B
Univ Of Florida, Gainesville
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML13353A174 (25)
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UFUNIVERSITY UFFLRD of College of Engineering PO Box 118300 UF Training Reactor Facility Gainesville, FL 32611-8300 352-392-2104 bshea@ufl.edu December 12, 2013 U.S. Nuclear Regulatory Commission 10 CFR 2.109(a) New License ATTN: Document Control Desk UFTR Operating License R-56, Docket 50-83 Washington, D.C. 20555-0001

Subject:

UFTR Responses to Request for Additional Information (ML113560528)

Attached are additional UFTR licensing basis documents in response to the RAIs dated January 6, 2012. The attached documents include Chapters 2 and 7 of the FSAR.

The UFTR licensing basis reconstitution efforts continue with remaining FSAR chapters and revised Operator Requalification program to be submitted at a future date.

This submittal has been reviewed and approved by UFTR management and by the Reactor Safety Review Subcommittee.

I declare under penalty of perjury that the foregoing and attached are true and correct to my knowledge.

Executed on December 12, 2013.

Brian Shea Reactor Manager cc: Dean - College of Engineering Reactor Safety Review Subcommnittee Facility Director Reactor Manager Licensing Engineer NRC Project Manager A-uzb The Foundationfor The Gator Nation An Equal Opportunity Institution

CHAPTER 2 SITE CHARACTERISTICS

Rev. 0 12/12/2013 Chapter 2 - Valid Pages i Rev. 0 12/12/2013 ii Rev. 0 12/12/2013 2-1 Rev. 0 12/12/2013 2-2 Rev. 0 12/12/2013 2-3 Rev. 0 12/12/2013 2-4 Rev. 0 12/12/2013 2-5 Rev. 0 12/12/2013 2-6 Rev. 0 12/12/2013 2-7 Rev. 0 12/12/2013 2-8 Rev. 0 12/12/2013 2-9 Rev. 0 12/12/2013 2-10 Rev. 0 12/12/2013 2-11 Rev. 0 12/12/2013 i

Rev. 0 12/12/2013 TABLE OF CONTENTS 2 SITE CHARACTERISTICS 2----

2 .1 G eog raphy an d D em og raphy ....................... . ...... ....... . ...... ....... ....... ......2-I1 2 .1 .1 S ite L o c a tio n a n d D e sc rip tio n ------. .------..------------ .................................-_2-I- 1 2.1.1.1 Specification and Location 2- I 2 .1.1.2 B o undary and Z o ne A rea M aps ---------------------------................. 2-.5 2 .1.1 .3 P o p u la t io n D is tr ib ut io n ........... . . ................. ..............................-- 2- .5 2.2 N earby Industrial, Transportation, and M ilitary Facilities ............................---2-5 2.2.1 Location and Routes 2-5 2.2.2 Air Traffic 2-5 2.2.3 A nalysis of Potential A ccidents at Facilities . ... .........................-- 2-6 2.3 Meteorology ------------------ ----------------- ----------------- 6 2.3.1 G eneral and Local C lim ate --- ............. ...... .... 2--.6 2.3.1.2 Humidity ---------. ---- ------------------.. .....---------------------------

2---6 2.3.1.3 Wind 2-6 2.3.1.4 Temperature and Precipitation-._. .................. .... ---- 2-7

.7-------

2.3.1.5 Severe Weather Phenomena 2-7 2.3.1.5.1 Tropical Storms and Hurricanes ----------------- 7 2.3.1.5.2 Tornadoes 2-8 2 .4 H y d r o lo g ic E ng in e e r in g .... ........................................................... ............. ..- 2-9 2.4.1 Flooding 2-9 2.5 Geology, Seismology, and Geotechnical Engineering ------------------------ -10 2.5.1 Regional Geology ------------------------------------------ 10 2.5.2 Site Geology --------------------------------------------- 1I 2.5.3 Surface Faulting ---------------------------- .........------------------- --- --------2--11 2.5.4 Stability of Subsurface Materials and Foundations 2- 11 2 .5.5 S tab ilities o f S lo p es . . . . . .... ...... ........ .-.1 1 2----------------------

2 .6 R e fe re n c e s ---------------------------------------------------------- .----------------------- 7-1 1

.-- ..... 2 LIST OF TABLES 2-1 Wind Data Summary for January 1, 1980 to December 31, 2009 for the Gainesville Regional A irport (Ref. 2.4) ........................................................... 6 ....................

2-2 Temperature and Precipitation Data Summary for May 1, 1960 to April 30, 2012 for the G ainesville Regional A irport (Ref. 2.3) ......... ........ . 2........................................7......

27 2-3 Alachua County Tornado Events from 1950 to 2013 -------------------------------- 8 LIST OF FIGURES 2-1 Map of the Greater Gainesville Area Showing Placement of University of Florida and Major Landmarks 2-2 2-2 Map of the University of Florida Campus ----------------------------------- 2-3 2-3 UFTR Location (Bldg. 557) on the University of Florida Campus 2-4 2-4 FEMA Flood Map Showing UFTR Location in Flood Zone 'X' -------.. . .----------------- 2-10 ii

Rev. 0 12/12/2013

2. SITE CHARACTERISTICS This chapter describes the site characteristics of the UFTR on the University of Florida campus including characteristics in the vicinity of the UFTR and their relation to the safety and operation of the UFTR.

The conclusion reached in this chapter and throughout this document is that the selected site is well-suited for the UFTR when considering the inherently safe design of the reactor and relatively benign consequences of the Maximum Hypothetical Accident (MHA). This is consistent with .the conclusions reached for the other non-power reactor facilities throughout the world. Many of which are located on university campuses, in hospitals, and other highly populated areas.

2.1 Geography and Demography 2.1.1 Site Location and Description The UFTR is located on the campus of the University of Florida in Gainesville, Florida. The city of Gainesville is approximately in the center of Alachua County, which is in the north-central part of Florida, approximately midway between the Atlantic Ocean and the Gulf of Mexico. The Gulf of Mexico is about 50 miles to the southwest and the Atlantic Ocean is about 65 miles to east.

2.1.1.1 Specification and Location The UFTR is located in the northeast quadrant of the main University of Florida campus approximately two miles from the historic center of the city (University Avenue and Main Street).

The UFTR location is approximately:

  • 20 meters south of the Reed Laboratory;
  • 40 meters west of Weimer Hall - Journalism College;
  • 90 meters east of Rhines Hall - Materials Sciences;
  • 130 meters north of the J.W. Reitz Union; and
  • 190 meters east of East Hall, the closest residence hall.

Figures 2.1, 2.2, and 2.3 illustrate the location of the UFTR with respect to the city of Gainesville and the UF campus.

2-1

Rev. 0 12/12/2013 Figure 2-1 Map of the Greater Gainesville Area Showing Placement of University of Florida and Major Landmarks 2-2

Rev. 0 12/12/2013 Figure 2-2 Map of the University of Florida Campus 2-3

Rev. 0 12/12/2013 Figure 2-3 UFTR Location (Bldg. 557) on the University of Florida Campus 2-4

Rev. 0 12/12/2013 2.1.1.2 Boundary and Zone Area Maps The map indicated in Figure 2-1 shows the property boundaries of the University of Florida campus. The site boundary lines are the same as the property lines. The locations of the principal structures in the vicinity of the reactor building are shown in Figure 2-3.

The operations boundary is the reactor building and annex (designated UF Bldg. 557), including the west fenced lot as necessary.

2.1.1.3 Population Distribution Based on 2010 U.S. Census Bureau data, the city of Gainesville, Florida has a population of 171,787 with a total population in Alachua County of 247,336 (Ref. 2.1). The University of Florida has a population (student and employees) of approximately 65,000 people.

The University of Florida houses approximately 9,500 residents in all of the student residence halls and family housing. The nearest to UFTR is East Hall which is located approximately 190 meters west and has a capacity of approximately 210 residents. East Hall is part of a series of buildings referenced as the Tolbert area capable of housing approximately 990 residents.

2.2 Nearby Industrial, Transportation and Military Facilities 2.2.1 Location and Routes Transportation routes located close to campus are shown in Figures 2-1 through 2-3. State Roads 121, 26 and 24, U.S. Highway 441 and Interstate 75 are well-traveled, major transportation routes through and/or around Gainesville. The primary usage of State Roads 121,26 and 24 and U.S. Highway 441 are for commuter travel to the University of Florida and to the center of the city. Interstate 75 is used primarily for commuter travel to/from surrounding cities and for tourist travel to South and Central Florida. Other uses for all of the above roads include shipment of dangerous, toxic or explosive substances; however such usage would be minimal particularly for those roads nearest the UFTR site, i.e., State Roads 26., 121,and 24 and U.S. Highway 441.

The UFTR location is approximately:

  • 450 meters south of the State Road 26;
  • 850 meters west of U.S. Highway 441;
  • 1300 meters north of State Road 24; and
  • 2400 meters east of State Road 121.

Since the reactor building is located between the Nuclear Sciences Building on the south side and the Reed laboratory building on the north, any explosion of transported materials would first have to exert its effect on both of these buildings. Although not immediately adjacent, the same protection is afforded on the east side by the Journalism Building and on the west side by the unoccupied Chiller Unit Facility. The location of the UFTR building in relationship to all nearby buildings and the campus in general provides for shielding and a protective effect from the forces of explosion on all sides.

There are no refineries, chemical plants, mining facilities, manufacturing facilities, water transportation routes, fuel storage facilities, military facilities, or rail yards located near the UFTR.

2.2.2 Air Traffic The Gainesville Regional Airport is the only airport in the vicinity. The airport is located on the northeast edge of Gainesville, approximately eight (8) kilometers northeast of the UFTR.

2-5

Rev. 0 12/12/2013 The Gainesville Regional Airport has two runways with a total of approximately 11,660 ft. of runway length (compass headings of approximately 2400 and 2800). The airport averages approximately 190 aircraft operations per day and has approximately 119 aircraft based on it, 95 of which are single engine aircraft (Ref. 2.2).

Based on the low probability of aircraft accidents, the relatively small number of operations, the size of most aircraft involved, the orientation of the runways, the distance between the UFTR and the airport, the relatively small areas of aircraft impact, and the protected location of the UFTR building in reference to other surrounding buildings, it is concluded that the probability for an aircraft accident affecting the UFTR facility is remote.

2.2.3 Analysis of Potential Accidents at Facilities Gainesville is primarily an education-related, small-business-oriented city. The areas surrounding the UFTR site and University of Florida campus are representative of most of Gainesville, consisting primarily of residential areas, apartment complexes and small businesses such as restaurants, retail stores, etc. A study of area activities shows that there are no significant industrial activities in this immediate area that could lead to potential accidents having an effect on the UFTR Reactor Building.

2.3 Meteorology 2.3.1 General and Local Climate Alachua County, in the north-central part of Florida, is located approximately midway between the Atlantic Ocean and the Gulf of Mexico. The average year in Alachua County may be divided into two seasons: the warm, rainier season and a cooler, drier season. The warm, rainier season runs from about the middle of May to the end of September. The cooler, drier season dominates the remainder of the year.

2.3.1.2 Humidity Relative humidity is highest during morning hours and generally averages between 89-95% throughout the year.

During the afternoon, humidity is generally lower with an average ranging fi'om about 55-64% during the warmer, rainier season and 49-60% during the remainder of the year (Ref. 2.3).

2.3.1.3 Wind A 30-year wind rose is used to describe the average wind speed and wind direction. This wind summary data is provided in Table 2-1 below.

Table 2-1 Wind Data Summary for January 1, 1980 to December 31, 2009 for the Gainesville Regional Airport (Ref. 2.4)

Direction - From Frequency Speed (m/s)

N 5.90% 3.35 NNE 4.50% 3.50 NE 5.20% 3.65 ENE 5.20% 3.71 E 7.50% 3.60 ESE 4.10% 3.50 SE 3.70% 3.55 2-6

Rev. 0 12/12/2013 SSE 3.10% 3.50 S 4.50% 3.60 SSW 3.30% 3.76 SW 3.50% 3.96 WSW 4.60% 4.32 W 7.50% 4.07 WNW 4.90% 3.60 NW 4.60% 3.40 NNW 3.80% 3.29 Calm 22.60% 0.00 Variable 1.60% 2.11 Mean Wind Speed = 2.81 2.3.1.4 Temperature and Precipitation Temperature and precipitation summary data is provided in Table 2-2 below.

Table 2-2 Temperature and Precipitation Data Summary for May I, 1960 to April 30, 2012 for the Gainesville Regional Airport (Ref. 2.3)

Average Climate Summary Month Maximum Temp (F) Minimum Temp (F) Total Precipitation (in)

Jan 66.5 42.5 3.27 Feb 69.4 45.1 3.55 Mar 75.2 49.9 3.72 Apr 81.1 55.1 2.22

-May 87.1 62.6 2.74 Jun 89.8 69.0 6.91 Jul 90.7 71.4 6.63 Aug 90.3 71.6 7.06 Sep 87.3 69.0 5.01 Oct 81.3 60.1 2.77 Nov 74.4 50.8 1.87 Dec 68.0 43.9 2.56 Annual 80.1 57.6 48.32 2.3.1.5 Severe Weather Phenomena 2.3.1.5.1 Tropical Storms and Hurricanes Tropical storms and hurricanes are not considered a great hazard at the University of Florida reactor site for three reasons. First, the likelihood of a hurricane traversing Alachua County is very small. Second, the severity of the storm is reduced by the overland movement necessary for a storm from the Gulf of Mexico or the Atlantic Ocean to reach the Gainesville area. Third, tidal flooding is prevented by the inland location of the UFTR site and there are no significant bodies of water near the UFTR site. Experience with the passage of past hurricanes indicates maximum gusts of approximately 60 miles per hour around the site. It should be noted that even thunderstorms occasionally develop gusts of this severity.

2-7

Rev. 0 12/12/2013 2.3.1.5.2 Tornadoes As shown in Table 2-3, a total of forty-two tornado events have been recorded in Alachua County from 1950 to 2013 (Refs. 2.4, 2.5). From this total, eight tornadoes reached a magnitude of F2 (Fujita Scale) with the last occurring in 1986.

Table 2-3 Alachua County Tornado Events from 1950 to 2013 Date Fujita Scale Deaths Injuries 6/8/57 F2 0 0 8/16/64 Fl 0 0 9/21/66 Fl 0 0 9/28/66 F2 0 0 12/25/69 Fl 0 0 2/3/70 F2 0 0 5/11/71 Fl 0 0 4/4/73 F2 0 0 1/25/75 FO 0 0 7/6/76 F1 0 0 6/21/77 Fl 0 0 4/19/78 F2 0 6 5/1/78 FO 0 0 5/4/78 F2 0 4 6/21/79 Fl 0 0 5/25/80 Fl 0 0 7/6/80 Fl 0 0 10/28/80 Fl 0 0 3/22/81 FO 0 0 2/2/83 F2 0 4 6/21/83 Fl 0 0 6/30/85 Fl 0 0 3/14/86 F2 0 0 7/9/87 FO 0 0 8/8/90 FO 0 0 9/28/90 FO 0 0 6/13/92 FO 0 1 3/12/93 F1 1 4 10/30/93 FO 0 0 10/30/93 FO 0 0 1/3/94 FO 0 0 10/30/94 FO 0 0 4/8/95 FO 0 0 2/2/96 FO 0 0 7/20/02 FO 0 0 4/25/03 FO 0 0 4/25/03 FO 0 0 9/5/04 FO 0 0 8/3/05 FO 0 0 12/16/07 EFI 0 0 2/26/08 EFO 0 0 3/24/12 EFO 0 0 2-8

Rev. 0 12/12/2013 According to statistical methods provided by Thom (Ref. 2.6), the probability per year of a tornado striking a point within a given area may be estimated using Equation 2-1 as follows:

ZT P - Equation 0-1 A

where symbols are defined as follows:

P = the mean probability per year of a tornado striking a point within area A.

Z = the geometric mean tornado path area, square miles.

T = the mean number of tornadoes per year in the area.

A = the area of concern, square miles.

The value ofT (mean number of tornadoes per year) is very conservatively taken as 1.0 per year for the 63 year period (1950-2013) for Alachua County. Based on data reported by Thom (Ref. 2.6) for midwest tornadoes, an average tornado path area is about 2.82 square miles which is the applicable but conservative value used for Z. Using the value of A equivalent to the total land area of Alachua County (965 square miles) in which the UFTR site is located, a value of P = 2.92 x 10-3 /year is calculated as the mean probability per year of a tornado striking within the UFTR site.

This probability of such a tornado striking within the UFTR site (reactor building occupies less than an acre) is conservative because the mean tornado path area in Florida is less than the national average used in the calculation. In addition other nearby campus structures surrounding the reaclor building provide significant protection.

The mean recurrence interval, R=I/P, of a tornado striking a point anywhere in which the site is located is, therefore, about 342 years. However, in the period from 1950 to 2013, only 25 property-damaging tornadoes have been reported in Alachua County, Florida where the site is located (also equivalent to a smaller probability of P= 1.16 x 103 /year which further emphasizes the conservatism of the P = 2.92 x 10 3 /year value calculated above). Though this probability is conservative and very low, tornadoes are considered to be the most likely natural disaster to affect the UFTR site.

2.4 Hydrologic Engineering 2.4.1 Flooding There are no dams in the University of Florida - Gainesville area that could affect the reactor site in case of failure. No major streams or rivers run near the site area which is well inland removing the potential for tidal flooding. Because of this, and the well-drained location of the UFTR site, no special consideration is given to floods in the UFTR design.

Exhaustive studies have indicated no record of any major flood in the general UFTR site area during the past 100 years. Figure 2.4 shows the FEMA flood map in effect since June 2006 illustrating that the UFTR is located in an area designated Zone X (areas outside the potential floodplain). Portions of Lake Alice and the Wastewater Treatment plant are shown near the bottom of Figure 2.4 in an area designated Zone A (nearest potential floodplain - no base flood elevations determined).

Finally, emergency flood procedures are addressed in the UFTR Standard Operating Procedures so no further consideration is necessary here.

2-9

Rev. 0 12/12/2013 Figure 2-4 FEMA Flood Map Showing UFTR Location in Flood Zone 'X' 2.5 Geology, Seismology and Geotechnical Engineering 2.5.1 Regional Geology The solid bedrock in this area is porous and cavernous Ocala limestone which occurs in a broad truncated dome with its crest in Levy County southwest of Gainesville. The Ocala formation is overlain by other porous 2-10

Rev. 0 12/12/2013 limestones and semipermeable sandy clays (Hawthorne formation). This is capped by loose surface sands.

2.5.2 Site Geology The specific site geology is very similar to that of the region as a whole. Most of the Gainesville area and that part of the campus north of Radio Road, including the UFTR site, is underlain by a loamy fine-sand type of soil.

This was derived from residual Hawthorne formation and is characterized by a typical slope of 2 to 7 percent, light brown or brownish grey surface soil, light yellowish brown or pale brown subsoil, nearly loose to loose with good natural drainage.

2.5.3 Surface Faulting There is ample evidence that Florida has been stable and free of earthquakes for about one million years, and it is considered to be one of the most stable areas in the entire United States. There have, however, been several small earth tremors which have caused slight damage such as small cracks in plaster wall in some areas of the state.

2.5.4 Stability of Subsurface Materials and Foundations The limerock formations are very stable geologically as indicated by the relative absence of earth movement activity in Florida over the past million years.

2.5.5 Stability of Slopes There are no rocks or soil slopes of concern for the UFTR site. The general downward incline toward the west and south eliminates the possibility of drainage or flooding problems. The general site and area topography have shown that this area is very stable. There is no danger of landslides since the general slope of the land is a gradual incline with no sharp contours.

2.6 References 2.1 United States Census Bureau, www.census.gov, 2010 Census.

2.2 Federal Aviation Administration - Gainesville RGNL Airport Master Record, www.gcrl .com, January 2013.

2.3 The Southeast Regional Climate Center, www.sercc.com 2.4 NOAA Online Climate Data Center, www.nc.dc.no.a..gov 2.5 Tornado Project, Florida Tornados 1950-1995, www.tornadoproject.coom 2.6 Thom, H.C.S., WMO Technical Note #81, 1966.

2-11

CHAPTER 7 INSTRUMENTATION AND CONTROL SYSTEMS

Rev. 0 12/12/2013 Chapter 7 - Valid Pages ii Rev. 0 12/12/2013 Rev. 0 12/12/2013 7-1 Rev. 0 12/12/2013 7-2 Rev. 0 12/12/2013 7-3 Rev. 0 12/12/2013 7-4 Rev. 0 12/12/2013 7-5 Rev. 0 12/12/2013 7-6 Rev. 0 12/12/2013 7-7 Rev. 0 12/12/2013

Rev. 0 12/12/2013 TABLE OF CONTENTS 7 INSTRUMENTATION AND CONTROLS 7-1 7.1 Design of Instrumentation and Control Systems..... ...... 7-1 7 .1.1 D esig n C riteria .................................. . .. ...... 7-1 7.1.2 Design-Basis Requirements 7-1 7.1.3 Systems Description 7-1 7.1.3.1 Reactor Power Measurements 7.1.3.1.1 Reactor Power Channel I 7.1.3.1.2 Reactor Power Channel 2 7-2 7.1.3.2 Process and Temperature Measurements 7-2 7.1.3.2.1 Primary Coolant System 7-2 7.1.3.2.2 Secondary Coolant System 7-3 7.1.3.2.3 Shield Tank System ..........

7.2 R eactor Contro l System - ..--------------- ............... ........... ------ ------ ----- ------ -----7-.-3 7-3 7.2.1 Control-Blade Drives . .. . ..... ........... -- 7 -4 7-4 7.2.2 Control-Blade Inhibits 7-4 7.2.3 Automatic Controls 7-4 7.3 Reactor Protection Systems 7.3.1 Trip Circuits 7-4 7.4 Emergency Safety Features Actuation System .......... ......... 7-5 7.5 Control Console and Display Instruments ........................... ...

--... .. ---. ------- 7 76 7.6 Radiation Monitoring System 7-6 LIST OF FIGURES 7-1 Operating Ranges of UFTR Nuclear Instruments 7-7 ii

Rev. 0 12/12/2013 7 INSTRUMENTATION AND CONTROLS Since the UFTR is a low power, self-limiting reactor, the instrumentation and associated controls are considerably simplified when compared to instrumentation and control systems of large power reactors. Many of the instrument outputs are shared between the systems.

The instrumentation and control (I&C) systems of the UFTR comprise the following subsystems:

  • Reactor Control System (RCS);

0 Reactor Protection System (RPS);

  • Process Instrumentation; and
  • Radiation Safety Monitoring Systems.

The system instruments are hardwired analog instrument type with the exception of portions of the temperature monitoring system that are of the digital system instrument type. Additionally, several data recorders have been replaced with digital data recorders.

7.1 Design of Instrumentation and Control Systems Two channels of neutron instrumentation provide the UFTR with independent, separate indication of reactor power from the source level to 150% of the rated thermal power.

The RCS is composed of four control-blade drive systems, two nuclear instrumentation channels, one automatic control system, one interlock system and one monitoring system.

The RPS is composed of the Control-Blade Withdrawal Inhibit System, Safety Channel 1, Safety Channel 2, and monitored parameters. The monitored parameters are both nuclear and non-nuclear or process variables.

7.1.1 Design Criteria The instrumentation and control system is designed to provide the following:

  • information on the status of the reactor and reactor-related systems; 0 means for manually withdrawing or inserting control rods;
  • automatic control of reactor power level; 0 automatic scrams in response to selected abnormal operating parameters or equipment parameters, and
  • monitoring of radiation and airborne radioactivity levels.

7.1.2 Design-Basis Requirements The primary design basis of the UFTR is the Safety Limit on fuel and cladding temperature.

The Excess Reactivity insertion accident described in FSAR Chapter 13 demonstrates that no automatic control or safety functions are needed to prevent reaching the Safety Limit. The Limiting Control Settings specified in the Technical Specifications are non-safety related trip set points chosen to ensure MODE I operation remains bounded by the thermal hydraulic analysis described in FSAR Chapter 4.

7-1

Rev. 0 12/12/2013 7.1.3 Systems Description 7.1.3.1 Reactor Power Measurements The two channels of neutron instrumentation provide the UFTR with independent and separate monitoring of the reactor power level. Figure 7-1 shows the operating ranges of the detectors used to monitor UFTR power levels.

7.1.3.1.1 Reactor Power Channel I Reactor Power Channel I provides the operator with period and measured power from source level to 150% of rated thermal power. The signals are provided from two detectors, a B-10 proportional counter and a fission chamber.

The detectors are connected to circuitry containing a pre-amplifier, a log amplifier, and a linear amplifier. Trips are provided for over power, short period, and loss of detector high voltage. A blade withdrawal interlock is activated for specific conditions impacting channel operability.

The period signal is obtained through a derivative circuit that produces a voltage proportional to the inverse of the reactor period. This is then amplified and displayed on a control panel meter that ranges in seconds from -30 to + 3 sec. An adjustable bistable circuit activates a trip, currently set at +3 seconds.

The linear amplifier accepts the linear current signal from the pre-amplifier. The output signal is then displayed as the power level on a linear scale ranging from I to 150% of rated power. An over power trip is set at 119% rated power resulting from operation of a bistable circuit. The channel also generates test signals to check the functioning of the channel.

7.1.3.1.2 Reactor Power Channel 2 Reactor Power Channel 2 provides the operator with measured power from source level to 150% of rated thermal power and can be used to maintain steady power level through an automatic flux control servo system. The signals are provided from two detectors, a compensated ion chamber (CIC) and an uncornpensated ion chamber (UIC).

Trips are provided for over power and loss of detector high voltage. A blade withdrawal interlock is activated for specific conditions impacting channel operability.

The CIC provides linear power level indication from just above source level to 100% of rated thermal power. The CIC is connected to circuitry containing a pico-ammeter with a multiple position range switch resulting in indicated power as a percentage of range switch position. The pico-ammeter sends a signal, which is a function of the linear indication of reactor power, to the servo amplifier as a part of an automatic reactor control circuit. At the servo amplifier, the signal is compared with the signal from the servo flux control.

The UIC provides power level indication from 1% to 150% of rated thermal power. The UIC is connected to circuitry containing an operational amplifier and an adjustable bistable trip. An over power trip is set at 119% rated power resulting from operation of a bistable circuit. The channel also generates test signals to check the functioning of the channel.

7.1.3.2 Process and Temperature Measurements 7.1.3.2.1 Primary Coolant System A primary coolant flow monitor, with sensor located in the primary fill line, indicates flow and trips the reactor if flow is below the set point.

A coolant flow switch, located in the return line of the primary coolant system to the primary coolant storage tank, initiates a reactor trip in case of a loss of return flow. This flow switch actuates only after the return line has been drained of water or flow stops.

7-2

Rev. 0 12/12/2013 A sight glass, attached to the north wall of the reactor room, shows the water level in the core allowing a visual check of the primary coolant level. A float switch activates the reactor trip system when the water level in the core is below the pre-set limit.

Temperature sensors are located at each of the six fuel box discharge lines to monitor water temperature from each fuel box. Additional sensors monitor the temperature of the bulk primary water going to and exiting from the core.

Temperature signal information is sent to an input module that converts the signal to a linearized voltage output.

These voltage outputs are sent to a data acquisition card that commands a relay board for alarming and trip conditions. The monitored temperatures are displayed on a temperature monitor virtual instrument (computer monitor) as well as on a paper recorder located in the reactor control room. Monitored temperature points exceeding preset levels will result in an audible alarm followed by reactor trip.

A resistivity meter enables on line monitoring of resistivity of the primary. The meter annunciates if system resistivity drops below an adjustable preset value.

To monitor water intrusion from any source into the primary equipment pit, a level switch in a small sump at the lowest point of the pit floor will activate an alarm upon collecting water at I in. above pit floor level. The primary equipment pit sump alarm annunciates at a control unit mounted on the east wall of the control room.

7.1.3.2.2 Secondary Coolant System A key operated switch inside the console rear door is used to switch secondary scram modes between well water (10 second trip delay) or city water (immediate trip) modes of operation. In either mode, the trip function is active only when reactor power is I%or higher.

In the well water mode, a reduction of flow to a pre-set limit will illuminate a yellow warning light on the right side of the control console. A further reduction of flow to another pre-set limit will illuminate a red scram warning light on the right side of the console, and will illuminate a red warning light on the secondary flow scram annunciator light. Approximately ten seconds later, the trip will occur. When in the city water mode, if water flow reached the pre-set limit the reactor will trip.

7.1.3.2.3 Shield Tank System A water level switch at the top of the reactor shield tank will trip the reactor when the water level drops below a preset value.

7.2 Reactor Control System 7.2.1 Control-Blade Drives The four control blades are positioned by control blade drives through a magnetic clutch power circuit which couples the blade drive shafts to the blade drive motors. Interruption of clutch current decouples the drive motor from the blade drive shaft allowing the blade to gravity fall to its fully inserted position. Control blade magnet power is controlled through the three-position key switch.

Twelve backlit push button switches are arranged in the center of the control panel in three rows of four vertical sets, one set for each control blade. Each set of switches contains a white DOWN switch, a red UP switch, and a yellow ON (magnet on) switch.

When the white DOWN light is illuminated, the control blade drive motor power circuit is prevented from drive action via the DOWN backlit pushbutton switch. When the red UP light is illuminated, control blades in manual control are similarly prevented from up motion. The yellow ON light is series-connected in the magnetic clutch power circuit so that if the yellow light is on. the magnetic clutch is energized; if the yellow ON light is off, the magnetic clutch is deenergized.

7-3

Rev. 0 12/12/2013 When any ON push button switch is depressed, magnet current is interrupted by actuation of the backlit switch, and the ON light remains extinguished for as long as the switch is depressed. If the control blade is above its down limit, the blade will gravity fall back into the core. Turning off the reactor key has the same effect. In the event of a loss of power, these blades fail safe, falling into the core by gravity.

The positions of the control blades relative to their lower limits are indicated on individual digital blade POSITION indicators mounted on the control panel.

Limit switches in the blade drive right angle gear box send a signal to the backlit control blade switches to indicate either full-in or full-out position. This also inhibits the control blade drive motor from actuating when the blade is at its limits of travel.

Wiper arm position indicators, mechanically coupled to the blade drive shafts via beveled gears, transmit blade position to the control console.

7.2.2 Control-Blade Inhibits Control blade withdrawal inhibits function to prevent blade withdrawal for the following conditions:

  • A source count rate of 2 cps or less;
  • A reactor period of 10 seconds or shorter; 0 Safety Channel I and 2 and wide-range drawer Calibrate (or Safety I Trip Test) switches not in "OPERATE" or "OFF" condition. This inhibit condition assures the monitoring of neutron level increases and prevents disabling protective functions; 0 Attempt to raise any two or more blades simultaneously when the reactor is in manual mode, or two or more safety blades simultaneously when the reactor is in automatic mode. This multiple blade withdrawal interlock is provided to limit the reactivity addition rate; Power is raised in the automatic control mode at a period shorter than 30 sec. The automatic controller action is to inhibit further regulating blade withdrawal or drive the regulating blade down until the period is greater (slower) than or equal to 30 seconds.

7.2.3 Automatic Control The UFTR Automatic Control System is used to hold reactor power at a steady power level during extended reactor operation at power and may be used to make minor power changes within the maximum range of the switch setting.

While the automatic mode of reactor control is selected, the manual mode of operation is disabled; the control mode switch must be placed back in MANUAL before the regulating blade will respond to its UP or DOWN control switches. The neutron flux controller compares the linear power signal from the pico-ammeter with the power demand signal and moves the regulating blade to reduce any difference, thereby maintaining a steady power level.

7.3 Reactor Protection System 7.3.1 Trip Circuits The UFTR facility is provided with two types of reactor trips. These reactor trips are classified into two categories:

Full-trip, which involves the insertion of the control blades into the core and the dumping of the primary water into the storage tank (this type of trip will dump primary water only if 2 or more control blades are not at bottom position);

7-4

Rev. 0 12/12/2013

  • Blade-trip, which involves only the insertion of the control blades into the reactor core (without dumping of the primary water).

One of five conditions must exist for the initiation of the Full-trip; these five conditions include:

  • Short Period (3 seconds or less);
  • High Power (119%);
  • Reduction of high voltage to the neutron chambers of 10% or more;
  • Turning off the console magnet power switch;
  • A.C. power failure.

The conditions that must exist for the initiation of a Blade-trip include:

  • Loss of power to Stack Dilution fan;
  • Loss of power to Core Vent fan/damper;
  • Loss of power to the deep well pump when operating at or above I kW and using deep well for secondary cooling;
  • Secondary flow below 60 gpm when operating at or above I kW using the well water system for secondary cooling ( 10 sec delay);
  • Secondary flow below 8 gpm when operating at or above I kW using city water for secondary cooling (no delay after initial 10 second time interval);
  • Shield tank water level 6" below established normal level;
  • Loss of power to primary coolant pump;
  • Primary coolant flow below 41 gpm (inlet flowrate);
  • Loss of primary coolant flow (no return flow);
  • Primary coolant level below 42.5";
  • Any primary coolant return temperature above I 55°F;
  • Primary coolant inlet temperature above 99°F;
  • Initiation of the evacuation alarm;

A set of annunciator lights is used to indicate scram conditions.

7.4 Engineering Safety Features Actuation System There are no engineered safety feature actuation systems.

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Rev. 0 12/12/2013 7.5 Control Console and Display Instruments All functions essential to the operation of the UFTR are controlled by the operator from the control console.

The reactor control panel contains the following control and indicating instrumentation:

  • A console power switch.
  • A three-position key switch.
  • A set of control-blade switches.
  • One set of switches for controlling the secondary system city water valve.
  • Four control blade position digital indicators.
  • Power Channel #1 meters and calibrate/test controls.
  • Power Channel #1 period meter and calibrate/test controls.
  • Power Channel #2 meter and test controls (UIC).
  • Power Channel #2 linear range switch (CIC).
  • Power Channel #2 recorder (CIC).
  • A mode selector switch for automatic or manual operation.
  • Reactor cell door monitors.
  • Reactor equipment control switches and annunciator lights.
  • Digital clock.
  • Pu-Be source alarm indicator.
  • Rabbit system solenoid switch.

When the console key switch is "ON", a red rotating beacon located in the reactor cell together with four "reactor on" lighted signs are energized. The "reactor on" lights are located on the outside of the east side of the Reactor building on the second floor level, on the entrance hallway leading to the control room, in the upstairs hallway, and on the west outside reactor building wall.

7.6 Radiation Monitoring System The reactor vent system effluent monitor consists of a GM detector and preamplifier, which transmit a signal to the control room to monitor the gamma activity of the effluent in the downstream side of the absolute filter before dilution occurs. The stack monitoring system also consists of a log rate meter-circuit and indicator, a recorder, and an auxiliary log rate meter with an adjustable alarm setting capability.

The area radiation monitoring system consists of three independent area monitors with remote detector assemblies, interconnecting cables, recorders, and count rate meters. Each detector has an energy compensated Geiger counter with built-in Kr-85 check source that can be operated from the control room. The signals from these detectors are sent directly to the log count rate meter and recorder. Two levels of alarm are provided (warning and alarm). Both levels latch in the alarm mode to preclude false indication ifa high dose rate saturates the detector. Any two of the monitors seeing a high radiation level will automatically actuate the building evacuation alarm. Actuation of the evacuation alarm automatically trips the reactor and the reactor cell air handler system.

The stack monitor and 3 area monitor modules in the control room are equipped with test switches and green "NO FAIL" lights that go out if the modules do not receive signal pulses from the detectors. Floating battery packs supply power to the units in the event of electrical power loss.

Air from the reactor cell is pulled through the airborne radioactivity monitor which is equipped with a recorder and an audible and visible alarm setting.

7-6

Rev. 0 12/12/2013 FISSION UNCOMPENSATED CHAMBER ION CHAMBER (XOMPENSATED i00-- ON CHAMBER I0S 10ot-I_-

IT' I I' 10 4

10 SAFETY SAFETY 10"1 CHANNEL I CHANNEL 2 2102 10 I l00 101 Ili, PROPORTIONAL is0 10 0.1 COUNTER 10'5 'o2 F610 -6 10"7 =--

10 WIDE I MULTIRANGE 10"5 EXTENDED RANGE WIDE RANGE LINEAR

-I A-10-1 Figure 7-1 Operating Ranges of UFTR Nuclear Instruments 7-7

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