ML20149M756

Bases & SA for Plum Brook Reactor Facility Protected Safe Storage Condition to Support Request for Amend to License TR-3

ML20149M756
Person / Time
Site:	Plum Brook
Issue date:	01/31/1997
From:	NATIONAL AERONAUTICS & SPACE ADMINISTRATION
To:
Shared Package
ML20149M753	List: ML20149M751 ML20149M755 ML20149M756 ML20149M758 ML20149M760
References
NUDOCS 9701270206
Download: ML20149M756 (30)

Text

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BASES AND SAFETY ANAIXSES FOR i

PLUM BROOK REACTOR FACILITY l PROTECTED SAFE STORAGE CONDITION ATTACHMENT 1 4

) TO SUPPORT REQUEST FOR AMENDMENT TO f LICENSE NO. TR-3 l DOCKET NO. 50-30 j

P 9701270206 961220 PDR ADOCK 05000030 p PDR

TABLE OF CONTENTS PAGE

1. I n t r o d u c t i o n . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 -

2. G e n e ra l I n fo rm a t io n . . . . . . .. . . . . .. .. . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . .. .. . . . . . . . . .. .. . . . . . . . . . . 2

3. Location.....................................................................................................2 4 . Re a c t o r T a n k . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

5. C o n t a in m en t Ve s sel . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . ... . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . 5

6. Primary Cooling Water System and Primary Pump House................ 7

7. A l a r m S ys t e m . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 1

8. Elec t rica l Sys tem... . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . ... . .. . . . .. .. . . . . . . . .. .. . . . . . . . .. .. . .. . . . . .. . .. . . . .. . . . 9

9. Qu a d ran t a nd Canal Sys tem ............................ .. . ....... ... ............. .......10  :

10. Ra diochemis try Labo ra tory...... ................. . ........ ....................11 I 7.............

11. H o t Dra in Sys t em . . . . . . . .. ... . . .. . .. . . . .. . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .. . . . . . . . . . . . . 12 l I

12. Ho t Labo ra to ry . . . . . .. . .. . . .. .. . . . . . . . . . . . .. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . .. . . . . . . . . . . 13 l

13. H o t Pi p e Tu nn el. . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . . . . .. . .. . .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . 13

14. Was te H a ndling B u ilding ... ...... . . .. ..... .. .. . ... ..... ..... .. . .. . ... ... .... .. ...... . .. . .. . . 14 i

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15. E me rgency Re tentio n Ba sin ................... ......................... ...... .... ......... .15

16. H o t Re t e n t ion A rea . . . . . . . . . .. . . . . . . . . ... . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

17. Con ta min a ted Air Systems..... .. . .. ........................................ ............. .18

18. Sa fety Analysis for Emergencies ....... ............. .... .. ..................... ...... ...19 18.1 Tornadoes and Severe Storm 18.2 Flooding 18.3 Earthquake 18.4 Fire 18.5 Sabotage 18.6 Bombing

19. Engineering P.udies and Equipment Transfer..................................... 24

20. E nviron men tal I mp a c t . . .. ... .... .. .. .. .. . .. . . .... ... .... ... ... .. . .. .. . . .. .. .. ... . . . ..... . .. .. . . 24

Attachment:

Figure 1 PBRF Plot Plan

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1. INTRODUCTION l

1 The revised Technical Specifications submitted with this application define the basis l for maintaining the protected safe storage condition of the NASA Plum Brook Reactor Facility (PBRF). The following definitions are applicable to these analyses:

l General Authorized Entry - Entry by people authorized by management with a

! legitimate need to enter the PBRF who have knowledge of the conditions, the hazards, and procedures of the facility or who are accompanied by someone with this knowledge.

Non-operable - A condition of a component or system which has been j intentionally disabled to prevent it from performing its intended function.

Protected Safe Storage - A custodial state of undefined duration characterized

by physical and procedural access control and periodic monitoring, maintenance and inspection.

Radioactive Materials l

Contaminated Material - Irradiated or non-irradiated items containing particles of radioactive materials on their surface.

Radioactive Material - Items which have been activated as a result of previous reactor operations. These items may also be contaminated.

Radiolo_cical Control Zones 1

l Magenta Zone - For purposes of contamination control, levels will be as low l as reasonably achievable but can exceed the magenta-yellow limit. For l purpcses of direct radiation control, a magenta zone is any area which could l expose major portions of a body to direct radiation levels of 100 mrem /hr or more.

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l Macenta-Yellow Zone - For purposes of verifying contamination control, levels will not exceed 100 dpm alpha /100 cm2 and 10,000 dpm beta-gamma /

100 cm2transferable; 2,500 dpm alpha and 8,000 dpm beta-gamma fixed.

. Magenta-yellow zone, for purposes of direct radiation control, is any area which l could expose major portions of the body to direct radiation levels from 2.5 to less than 100 mrem /hr.

l White Zone - Is an area with contamination levels so low that no protective i clothing is required. This area will have direct radiation levels less than 2.5 mrem /hr.

l l 2. GENERAL INFORMATION The Plum Brook Reactor Facility contains a non-operable test reactor and its inventory of radioactive materials generated as a result of previous operations. All reactor fuel and special nuclear material, as well as most waste byproduct material were removed from the facility.

I l 3. LOCATION l

The Plum Brook Station (PBS), a federal reservation of 6,400 acres controlled by the National Aeronautics and Space Administration (NASA), is located near Sandusky, Ohio. It is surrounded by a security fence which is patrolled daily. The PBS

Communication Center, which is manned 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> each day, is at the main gate and provides controlled entrance to the Station. A plot plan of the facility is included as Figure 1.

The Plum Brook Reactor Facility (PBRF) within the federal reservation, is an area of approximately 27 acres which is surrounded by its own security fence. Gates in both fences are locked or continuously manned. Access doors and windows of the buildings inside the PBRF fence are locked except during authorized entrance.

These controls will deter unauthorized entry. Penetration of these controls will not

be a radiological hazard to casual intruders since accessible areas outside and inside j the buildings are white zones.

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4. REACTOR TANK (RT) l 4.1 End Condition and Bases The Reactor Tank, located in the Containment Vessel, is surrounded by thick concrete walls. The tank contains the irradiated core structure and components. Penetrations into the RT are closed but are not necessarily gas tight. The RT is drained, defueled and covered by the shrapnel shields. The control rods and drives have been removed. Piping connected to the RT where practicalis separated and blank-flanged close to the RT to reduce the effective volume of the RT. The RT is purged with dry nitrogen through an absolute l filter to the stack. The purge is used to reduce corrosion of components inside the tank.

4.2 Safety Analysis The potential hazards associated with the reactor tank end condition are direct radiation, release of contamination with the nitrogen purge and loss of nitrogen purge flow. The high radiation level inside the RT, streaming through unshielded RT penetrations, would constitute an immediate and direct hazard to personnel. Shielding protects against this hazard. Three shrapnel shields are installed over the reactor tank and limit the radiation level outside the shield to 2.5 mrem /hr. The holes for the top most shrapnel shield lifting eyes are welded shut to prevent unauthorized shrapnel shield removal. All beam holes, through holes and instrument holes are shielded to reduce radiation levels at accessible areas in the quadrants to less than 100 mrem /hr. The radiation levels at the outer surface of the concrete biological shield surrounding the reactor tank and at accessible areas within the quadrants are less than 100 mrem /hr. Additional shields necessary to attain this value at penetrations are tack welded in place. Radiation survey confirms that shielding is adequate for all quadrant accessible areas classified as magenta-yellow zones. By exercising the control required for a magenta-yellow zone, the hazards due to direct radiation are minimal.

f It may be possible for the nitrogen purge to become a vehicle to release radio-

, contaminants into the purge piping and possible release into the environment.

Particulate material inside the 9-foot diameter reactor tank is not likely to be I 3 l

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j disturbed by the low flow (less then 10scfh) gas purge. Even if disturbed and l picked up by the gas, these particles would be removed by the absolute filter

, before the gas vents to the stack. Typical maximum measured airborne  ;

particulate concentrations for tritium are 2.4 x 10 4 ci/ml, well below the j Derive.i Air Concentration (DAC) for occupational worker limit of l 2.0 x 10-5 ci/ml. Thus particulate contamination of the nitrogen purge gas is  !

not considered a hazard.

l. Found during our Engineering Study effort to date (Section 19), tritium (H3) is I a constituent in the nitrogen purge gas. The tritium originates from beryllium metal in the reactor core box which contains trapped tritium gas as a result of previous neutron activation. Tritium is capable of slowly migrating out of the beryllium molecular lattice. As this occurs, tritium diffuses into the purge gas l

and is released to the environment from the top of a 100-foot high vent stack.

A preliminary evaluation of the existing tritium data concludes that with L atmospheric dilution, stack release of tritium does not exceed the Derived Air Concentration limit for an unrestricted area. The tritium monitoring at the stack is included during the normal facility monitoring. j l l l Prolonged loss of nitrogen purge could permit air to enter the RT. This could result in the formation of nitrogen / oxygen compounds by radiolytic reactions.

Some of the reaction products are corrosive snd toxic. The corrosion action of l the nitrogen / oxygen compounds could cause structural damage and potentially

! release corrosion products into the purge gas exhaust. The toxic properties of l nitrogen / oxygen compounds are important only if personnel are exposed to ,

them and this situation is not considered likely. To prevent buildup of

, nitrogen / oxygen compounds, the RT purge flow is monitored for loss of flow, i i Because the corrosion rate would be slow, loss of nitrogen purge and  ;

replacement of the nitrogen with air would result in no significant attack on structural components even after several hours of exposure. Except for special tests or maintenance, nitrogen purge will be reestablished under procedural control within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. ' The continuing need for nitrogen purge of the RT is periodically reviewed.

The degree of hazards associated with the RT end condition is acceptable.

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5. CONTAINMENT VESSEL 5.1 End Condition and Bases All readily accessible areas of the Containment Vessel (CV) are decontaminated to a white zone. Two primary openings allow the CV to breathe through absolute filters to the atmosphere. Personnel openings into the CV are closed to the outside except for one door which is locked and monitored by an l intrusion alarm. The truck door is closed and dogged in place. This door may be opened on a temporary controlled basis to accommodate transfer of equipment too large to fit through the personnel door. All liquid process lines which penetrate the CV are drained and blank flanged or capped. The quadrants, canals and sumps are drained and the sumps are non-operable.

Solid radioactive equipment and components are stored in the quadrants or hot caves.

These CV end conditions are designed to prevent unauthorized entry and to prevent contamination spread by water. Restricting CV entry to one locked and alarm monitored door precludes unauthorized access to the CV. Isolation of liquid process lines from the CV eliminates a source of water. CV flooding by other means, e.g., weather or ground water, is not considered possible due to the complete continuity of the CV structure.

The CV is served by a failing cathodic protection system. Ultrasonic measure-ments of the metal wall below ground show essentially no change in the 3/4-inch metal wall thickness over the past 24 years. Results of ultrasonic measurements indicate that corrosion is within acceptable levels. The need for continuing a cathodic protection system is periodically reviewed. The

, Cathodic Protection may be terminated after review and conclusion by the PBRF Safety Committee that no unreviewed safety question exists under the provisions of Section 50.59,10 CFR, part 50.

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i l 5.2 Safety Analysis i For the CV in a protected safe storage condition, two hazards are considered l credible. They are radiological hazard and an industrial type accident. The CV contains radioactive equipment and components stored in the quadrants, the l j canal and hot caves. Unauthorized entry could result in uncontrolled exposure to direct radiation and contaminated materials. Airborne radioactivity is not a ,

problem since 24 years experience has shown the stored material emits no I l

significant gaseous decay radioisotopes and the solid contamination does not l

l become air-borne. Personnel entering the CV are subject to potential industrial I accidents such as falls, sudden illness, etc. Each type of the credible accident, 1 l radiological and industrial, is covered separately.

l l 5.2.1 Radiological Hazard All radioactive or contaminated materials stored in the quadrants, canal or hot caves were shielded or decontaminated to activity levels not exceeding a magenta-yellow zone. No significant radioactive gas release j i

has been detected from any of the stored material. Material stored in the quadrants and canal have unshielded direct radiation levels less than 600 mrem /hr. and further the material is shielded so the accessible radiation levels do not exceed 100 mrem /hr. Hot Caves containing contaminated material are locked or welded closed. Unauthorized entry l mto a magenta-yellow zone is prevented by fences built around these areas. Fences are provided around the quadrants, the canal and at the l entry to the subpile room. Direct radiation levels at the fences are less than 2.5 mrem /hr. and are within limits for a white zone. Maximum airborne radiation levels are typically in the range of 1% DAC for beta-gamma, and less than detectable for alpha radiation.

! 5.2.2 Industrial Accidents Entry into the CV is controlled by written procedure. Authorized entry begins by telephone notification to the Communication Center of intent to enter and approximate duration. Opening the door activates the door alarm system. The alarm deactivates when the CV door is closed, locked and acknowledge button reset. The oxygen level inside the CV is 6

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regularly monitored. Typical readings are at or above 20.7% oxygen.

Fences and railings around the quadrants and canal prevent accidental i falls into these reservoirs. Commercial power failure inside the CV activate emergency battery powered lights to provide safe visibility.

These practices minimize the risk of an industrial-type accident to an acceptably low level. Authorized entry ends by leaving the CV, closing and locking the CV door, telephone notification to the Communication Center and alarm acknowledgment at the Reactor Security Control Building. If a tour does not end within a reasonable time, the Communication Center initiates a search to check the situation. It is

, concluded that the degree of hazard associated with the CV end t

condition is acceptable.

6. PRIMARY COOLING WATER SYSTEM AND PRIMARY PUMP HOUSE 6.1 End Condition and Bases The primary cooling water system was flushed, drained and purged with air. A portion of the system noted in the Reac+or Tank Section 4 is separated and blank flanged close to the RT. All valve operators which penetrate into the accessible areas of the Primary Pump House (PPH) are nonoperable. All motor

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driven devices are disconnected from their power sources. Personnel entryways into the PPH are locked. The PPH roof hatch plugs, which provide the only personnel access to the shielded rooms, are locked in place and sealed l against water entry. All PPH accessible area outside the shielded rooms are ]

decontaminated to a white zone level, j l

l l 6.2 Safety Analysis l l The hazards associated with the end conditions are personnel exposure and l spread of contamination. Entry into the shielded PPH rooms may bring personnel into a magenta-yellow and perhaps a magenta zone where they j would be subjected to both direct radiation and transferable contamination. l Seepage of water into the shielded rooms through the roof hatch plugs due to weather will only spread transferable contamination within the shielded room. )

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As noted above, all accessible areas outside the shielded rooms are a white zone. This ensures that personnel on routine entrance of the PPH will not be exposed to transferable contamination. Further, because of the shielding walls, direct radiation from the shielded room is reduced to white zone levels in accessible areas.

The shielded rooms of the PPH are established as magenta or magenta-yellow zones, as appropriate. The rooms are posted and the roof hatch plugs locked in place. Also, the crane hoists which are used to lift the reof hatch plugs are deactivated. Thus, unauthorized entry is prevented.

Weather seals for each of the roof hatch plugs keep rain water from entering the shielded rooms. These seals are periodically inspected to ensure their integrity. In addition, periodic remote inspections for water are made in the shielded rooms. If water is discovered in the rooms, the water will be sampled and disposed of under health physics' control.

It is concluded that the degree of hazard associated with Primary Cooling Water  !

System and Primary Pump House end conditions is acceptable. I

7. ALARM SYSTEMS 7.1 End Condition and Bases All alarms are designed fail safe, i.e., any monitored abnormal condition l l

including loss of electrical power will indicate an alarm condition. The alarms connect to a summary alarm panel at the Plum Brook Station Communication l Center which is continuously manned to provide response to an alarm within l one hour.

7.2 Safety Analysis Alarm system failure could prevent monitoring of off-normal conditions with no indication when monitoring stopped. The most significant undetected event would be unauthorized entry into the CV. An intruder could spread contamination as well as become overexposed to radiation. Alarm system j failure is detected by using fail safe design. Off-normal conditions, including l 8 l

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l power and system failure, activate an alarm at the Plum Brook Station  ;

l Communication Center.

l It is concluded that the degree of hazard associated with the Alarm Systems end conditions is acceptable.

8. ELECTRICAL SYSTEMS l 8.1 End Condition and Bases

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All facility electrical needs are provided by a commercial power system. After

! loss of electrical power to the facility, loads automatically reenergize upon  ;

restoration of power.

l 8.2 Safety Analysis Commercial power has demonstrated high reliability at the PBRF. During the l

past 24 years, only two occurrences led to an outage greater than two hours.

l The loss of electrical energy will affect the motor-driven sump pumps and i facility lighting. In the event of a power loss, some flooding may occur.

However, an emergency generator is available to supply power to the reactor building sump motors. The response time to energize the generator is typically l under 20 minutes which is considerably less than the two hours required to l overflow the well pits. The water flow into the sump pits does not vary j significantly thrcughout the year, so flooding is not likely. Hazards associated with flooding an covered in Section 18.2. )

, Facility lighting is used primarily by inspection and maintenance personnel l

after their entrance into the facility. Loss of lighting during these visits could be hazardous, particularly in the containment vessel with no natural lighting j source. To prevent a hazardous situation, strategically located battery power emergency lights actuate automatically upon loss of electrical power. These units provide ample lighting for personnel to safely find their way from the buildings.

It is concluded that the degree of hazard associated with the Electrical systems end conditions is acceptable.

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9. OUADRANT AND CANAL SYSTEM 9.1 End Condition and Bases l The quadrant and canal systems are located in the CV, Reactor Building and the Hot Laboratory. The quadrants and canals (QC) were cleaned, flushed, drained ,

and are dry. The deionizer tanks and the filter housing were flushed and left dry. Resins and filter elements were removed and disposed of as contaminated waste. Radioactive materials are stored in the quadrants. Some material, such l

as spent fuel storage baskets, underwater cutoff saw, supporting tools, and j hardware are stored in Canal G. All QC are magenta-yellow zones. Ladders l and other means of access to the QC floors are removed or barricaded.

Additional fence and railing were provided around the QC These end conditions for the QC were chosen to protect personnel and provide a suitable storage location for radioactive or contaminated hardware. Access to these materials is readily controlled.

9.2 Safety Analysis The hazards associated with the end conditions for the QC are radiological and

industrial. . The radiological hazard is direct radiation exposure or contact with l transferable contamination. Industrial hazards are those typical for security j tours of an industrial establishment during non-work hours. Each type of the hazard, radiological and industrial, is covered separately.

9.2.1 Radiological Personnel could be subjected to both direct radiation and transferable contamination from materials stored in the QC. As noted previously, the QC are magenta-yellow zones. As such they are posted and entrance is controlled. Personnel are excluded from such zones by l railing or fencing. Airborne contamination is not considered to be a problem because none of the stored radioactive materials has significant gaseous decay radio-isotopes and solid contamination is not i expected to become airborne. See Section 5 on Containment Vessel for j further discussion on radiological control. It is equally applicable for ]

4 this section.

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The QC clean-up deionizer tanks and filter housing have all resins and filter elements removed, the interior surfaces were flushed and left dry.

The exterior surfaces are decontaminated to white zone level while the interior surfaces, from a transferable contamination standpoint, are considered a magenta zone. The interior surfaces of these units are inaccessible to personnel. The outside of the tanks and filter housing are posted as areas containing radioactive material. Further, the building (Fan House) where these units are located is locked and under key control for authorized entry. These steps reduce the potential of contamination by the QC cleanup units.

9.2.2 Industrial Accidents The Section 5 on Containment Vessel describes the industrial hazards considered and the precautions taken. This Section should be referred to for consideration of the QC inside the containment vessel.

Entry into the Reactor Building and canals is controlled by established procedures. The only apparent accident situation associated with the canals are falls. This event is unlikely because of the fencing or railing l

located around the canals as demonstrated during the past 24 years.

Battery-powered emergency lights ensure adequate lighting is available.

The entries are monitored by approved procedures governing entry of persons into PBRF (Buddy System).

It is concluded that the degree of hazard associated with the QC end condition is acceptable.

10. RADIOCHEMISTRY LABORATORY 10.1 End Condition and Bases All chemicals, consumable supplies and unnecessary equipment were removed. The fume hood systems were vacuumed and cleaned as well as j t

practical. The filters were removed and fan power was disconnected. Doors on the fume hoods were made secure to prevent opening. The hoods are maintained in a dry condition and are posted. j 11 l

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l 10.2 Safety Analysis The exhaust hoods in the Radiochemistry Laboratory contain some residual contamination from use during previous reactor operation. The contamination adheres to the inside floor, walls and ducting of the exhaust l hood system. The hazard associated with the end conditions is the spread of contamination. Contamination spread is minimized by access prevention.

The exhaust hood doors can not be opened to expose any contamination.

l It is concluded that the degree of hazard associated with the Radiochemistry Laboratory end condition is acceptable.

11. HOT DRAIN SYSTEM l

11.1 End Condition and Bases The hot drain system and all floor drains were flushed, drained and sealed against water. The sumps were flushed, cleaned to a practical extent, and sealed. The sump pump motors are disconnected at the motor control center circuit breakers and are tagged out. The end conditions were selected to prevent the hot drains and sumps from spreading contamination.

11.2 Safety Analysis Spread of radioactive contamination and direct radiation are the only credible l hazards associated with the hot drain system. If water could enter the hot drain system, become contaminated and then flow into a cold sump, subsequent spreading of the contaminated water could result. The cold sumps are active l sumps that discharge into the PBRF drainage system and flow off-site into Plum Brook. By sealing the hot sumps and hot drains, spread of contamination is prevented. The seals will be periodically checked. Exposure to direct radiation is prevented by the use of fenced and locked radiation control zones.

! It is concluded that the degree of hazard associated with the hot drains end l

condition is acceptable.

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12. HOT LABORATORY 12.1 End Condition and Bases The seven hot cells were decontaminated to a practical level and contaminated i hot lab equipment and tools are stored in these cells. The hot cell doors are locked closed. Other areas containing residual contamination are enclosed by i fences or barriers and are posted. The Hot Dry Storage area contains radioactive and contaminated materials from previous reactor operations. The 80 ton access door to the Hot Handling room entrance to the Dry Storage area is locked closed.

1 12.2 Safety Analysis Hazards associated with the end conditions are personnel exposure and spread of contamination. Personnel exposure is prevented by the biological shielding design of the Hot Laboratory and limited access through lock and key. Limited access with procedural control prevents contamination spread by personnel.

Contamination spread by water has been no problem as verified by inspections over the past 24 years.

It is concluded that the degree of hazard associated with the Hot Laboratory end condition is acceptable.

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13. HOT PIPE TUNNEL 13.1 End Condition and Bases The Hot Pipe Tunnel was decontaminated to a level as low as reasonably

! achievable and is kept dry. Water which cannot be prevented from leaking into the contaminated area of this underground tunnel will be prevented from escaping.

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Process piping inside the HPT contains some residual contamination from use i during previous reactor operation. Dams and collectors are installed to prevent migration of water into and out of the contaminated area. The hazard 13

i associated with the HPT is spread of contamination. Twenty-two years I

experience shows the end conditions to be effective in minimizing spread of l contamination by restricting access into the closed systems, controlling access

! into the HPT and eliminating water sources.

1 It is concluded the degree of hazard associated with the HPT end condition is acceptable. l l 14. WASTE HANDLING BUILDING 14.1 End Condition and Bases The Waste Handling Building was decontaminated to a practical level. This building contains radioactive materials and equipment from previous reactor operations. Areas containing residual contamination are enclosed by fences or l

barriers and are posted. Doors leading to the evaporator room and waste l

l packaging room shall be locked closed. Access doors to the Waste Handling Building shall also be locked closed.

I 14.2 Safety Analysis Hazards associated with the end conditions are personnel exposure and spread of contamination. Personnel exposure is prevented by posted fences and barriers. The direct radiation at these fences and barriers is less than 2.5 mrem /hr. which is equivalent to the limits of a white zone. Contamination

! spread by water has been no problem as verified by inspections over the past twenty-two years.

, It is concluded that the degree of bazard associated with the Waste Handling Building is acceptable.

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15. EMERGENCY RETENTION BASIN 15.1 End Condition and Bases The Emergency Retention Basin (ERB) was drained and the drain line leading to the' ditch remains open to prevent accumulation of rain water. The bottom of the earthen. ERB contains areas with soil having trace quantities of contaminated material, however, typical maximum measured runoff activity levels are 7.1 x 10 4 ci/ml for beta-gamma, and less than detectable for alpha radiation. The supply line is blanked shut and the supply pumps were removed.

15.2 Safety Analysis The hazard associated with the ERB end condition is release of contaminated water or soil if the drain plugged permitting accumulated water to damage the a basin earth walls by excessive water. This hazard is very unlikely since the ERB contains eight-foot-high walls and the only water source to the basin is falling l rain water. Normal yearly rainfall does not exceed 48 inches, therefore, the basin could hold over a year's water supply with no threat of damage.

i Any large accumulation of water would be discovered on routine periodic inspections and would be corrected. Even if a break occurred, any residue would settle and accumulate in an adjacent field inside the PBRF fenced area. j It is concluded that the degree of hazard associated with the ERB end conditions is acceptable.

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16. HOT RETENTION AREA (HRA) l 16.1 End Condition and Bases Each of the tanks are flushed, drained, cleaned to a practical extent and left dry.

HRA transfer pumps are nonoperable. All personnel accesses to the area, l

except one to the annulus and one to the tunnel area, are closed against weather and welded against unauthorized entry. The authorized entries are j

locked to permit authorized inspections. All ventilation louvers which open to the atmosphere are closed. The exhaust vent to the stack breathes through an absolute filter.

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zone level. The HRA ground water sump pump is activated by high water level. The sump is monitored for high water level.

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16.2 Safety Analysis The hazard for the HRA under the end condition are spread of contamination

! resulting from entry into the HRA and major damage to the tanks and associated components by floating of the tanks. Each of these events will be covered separately below.

l 16.2.1 Spread of Contamination The tanks are to be maintained empty and all isolation valves in the I lines to the tanks are closed and sealed. Airborne contamination from the tank interior is also unlikely because of the relatively clean surfaces and the absence of any significant decay products which are gaseous. The only credible way for contamination to spread from the HRA is by an intruder. All other ways for contamination to spread are unlikely. If rain entered the weather covers, the quantity of liquid would be small based on previous experience, and readily removed under radiological control after discovery during routine inspection.

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Access to the PBRF requires the passage through the Plum Brook Station and PBRF fences. To enter the HRA, the intruder must disable a lock I l and climb down into the pipe chase. Since the pipe chase is a magenta-l yellow zone, it is possible for transferable contamination to be removed l I l by the intruder.

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The events described above, while credible, are highly unlikely. Passage l of a intruder across two locked or manned fences in both directions i without observation is possible; however, selection of the HRA for entrance by the intruder is unlikely. The facility is not only innocuous I in appearance but does not contain items of significant value. Even if l the intruder should enter the HRA, become contaminated, and leave, l

the amount of transferable contamination carried on the intruder would not be significant in terms of personnel exposure hazard or widescale spread of the contamination. Thus, it is concluded that unauthorized entry into the HRA is very unlikely and if the event should occur, the magnitude of the contamination problem would be insignificant.

l 16.2.2 Floating of Tanks The HRA tanks are housed underground, in a large concrete vault.

Footer drains around the vault lead to a ground water sump which l

l mamtains the ground water level below the tank bottoms. In the event this sump pump failed and the ground water level rose sufficiently high l

to float the tanks, it is conceivable the tanks could erupt through the roof of the vault. This would result in major damage to the facility, however, the relatively low level of contamination is of little concern. A high water level alarm provides early warning for prompt action to reduce this occurrence.

It is concluded that the degree of hazard associated with the HRA end condition is acceptable.

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17. CONTAMINATED AIR SYSTEMS i

l 17.1 End Condition and Bases t

The Contaminated Air system was shutdown after being vacuumed, washed, and purged clean through absolute filters. The roughing filters, prefilters and I

! high efficiency absolute filters were removed. Fan motors are disconnected.

l Air controls are deenergized and vented to atmosphere. All valves and dampers are fixed in a closed position and where applicable the piping and duct inlet and outlet openings are blocked. This arrangement restricts air movement within the piping. The main entry ways to the vent stack were

! welded closed. The stack drain line to the hot drain system was disconnected to preserve hot drain isolation and the hot drain lines were capped.

Compared to the operating mode, the Contaminated Air System end l conditions provide a reduced level of contaminants in the vent lines and areas l they service which vent to the stack. This was accomplished by high velocity air purging with manual cleaning to minimize contaminants in accessible l

areas.

17.2 Safety Analysis The only possible hazard is a release to the stack of contaminants in the system. This occurrence would spread contamination to the environment.

l The impact of this event is a function of the kind and quantity of contaminants released. A systematic cleanup was performed to remove contaminants from the Contaminated Air System. Air sample monitoring of selected areas 1

mcluding the PBRF stack produces typical maximum measured activity levels of less than detectable for alpha and beta-gamma sources. It is concluded that the degree of hazard associated with the Contaminated Air Systems end condition is acceptable.

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18. SAFETY ANALYSIS FOR EMERGENCIES 4

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18.1 Tornadoes and Severe Storms Tornadoes and severe storms are covered in Section 6.3.1 of the Final Hazards 1

Summary, NASA Plum Brook Reactor Facility, Part I. Statements made j therein, which are not related to reactor operations, are still applicable.

, A tornado is not expected to cause physical damage to the reactor tank or the Primary Pump House. The reactor tank is located below ground level inside the containment vessel. The Primary Pump House is constructed'of reinforced

[ concrete. All magenta zones are contained within heavy process equipment of i

substantial steel or concrete structures and therefore their containment should )

not be compromised by a tornado. Several magenta-yellow zones exist in the Reactor Building and auxiliary buildings where damage is possible.  ;

j However, the inventory of radioactive materials capable of release is much smaller than when the reactor facility was in operation. Tornado damage of the buildings is not expected to release significant amounts of radioactivity.

Severe storms could cause flooding, power failure, or lightning damage. A power failure could be tolerated. Lightning damage could not cause release of radioactive materials, but could cause a fire. Both fires and flooding are i covered in separate sections.

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The hazards associated with tornadoes and severe storms are acceptable since the radioactive inventory and the potential for spread of contamination are lower than during reactor operation.

18.2 Flooding Flooding could cause the release of radioactivity,if flood water washed away radioactive materials contained within the facility. Examples of magenta-19

_ _ .- . . , _ _ . __= . - . . - - . - . _ . . _ _-.. - -

! yellow zones having surface contamination are: (1) the hot sumps and hot drains, (2) the Primary Pump House, (3) Containment Vessel, (4) the quadrants l and canals where radioactive and contaminated materials are stored, (5) the l

l Hot Retention Area, and (6) other magenta-yellow zones in the facility. j I

l As discussed in Section 8, the floor hot drains leading to hot sumps and the hot j 1

sumps are sealed against water. Thus, entrainment and spread of l

contaminants by water is not credible. Periodic inspection is used to ensure seal effectiveness.

As discussed in Section 5, the Pump House roof hatch plugs have~ weather seals 1

which are maintained. If a seal should fail, some water could enter the rooms but would be trapped there until cleaned up under health physics control.

Again, spread of contaminants is not credible.

As discussed in Section 3, the process liquid lines were isolated from the CV.

l Further, the CV is a continuous steel shell protected by ground water pumps outside the CV. Even if water entered the CV, spread of contamination outside the CV is not credible.

There is a possibility that some water (such as from a window break) could enter a canal in the Reactor Building. However, it is not credible that a canal would be filled, since the canals are 25 feet deep. Thus, any water entering l would be contained until cleaned up under health physics control.

As stated in Section 14, entrance of water through or around the HRA weather l covers into the pipe chase is unlikely. Even if it occurred, the quantity of liquid would be manageable and it would be cleaned up under health physics control.

There are several other areas in the PBRF which are magenta-yellow zones.

Flood water could conceivably wash contaminants from these areas to cold 20

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L l sumps. Examples of these are the lowest level of the Reactor Building (RB), the

! basement of the Waste Handling Building (WHB), and the Hot Pipe Tunnel ,

(HPT).  ;

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j History shows that water from a very hea.3 'orm once entered the -15 foot level of the RB. It flowed to the lowest level of the building to a cold sump.

No spread of contamination occurred. To preclude this event from recurring l

l the following actions were taken:

l i a. The locations where surface water entered the RB were identified. These l

were a pipe trench, an air intake, and the RB sills. The trench and air intake l were closed, a dam was built to isolate surface water from the RB wall and j the trench was modified to provide better drainage from the RB.

l b. Procedures require an inspection tour of PBRF after every heavy storm.

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! Action was also taken to protect the WHB against water. During the r

aforementioned storm, small quantities of flood water entered the WHB.

Areas where the surface water entered are dammed and covered. Dams are also constructed at the evaporator and waste packaging rooms where white j zone levels are exceeded. The dams prevent uncontaminated water from entering the rooms and contaminated water from leaving the rooms. Any water found in the rooms will be cleaned up under health physics control.

The Hot Pipe Tunnel area was decontaminated to the greatest practical i

extent. The decontamination did not achieve a white zone level, so a dam was built across the HPT at the Fan House (FH) interface. Even under the severest weather only small seepage of water has entered the HPT. The dam effectively blocks water from spreading into the FH (HPT slopes to FH).

Periodic inspection at the dam is made for water buildup. If water needs to be removed, thia will be accomplished under health physics controls.

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i The hazards associated with flooding are acceptable. J i i i

18.3 Earthquakes i Earthquakes are covered in Section 6.3.3 of the Final Hazards Summary.

Because of the low probability of a strong earthquake and the nature of the [

[ i radioactive materials stored in the Reactor Facility (no liquids or gases), the risk associated with release of radioactive materials due to an earthquake is acceptable.

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l 18A Fire Likely sources of fire are open flames, electrical wiring, lightning,.and sparks l from grass fires in the local area. Procedures prohibit smoking at the PBRF.

l l Combustibles were removed as much as is practical from areas where radioactive materials are stored. A fire in any magenta zone is not deemed credible because of the lack of combustible materials.

l l The only significant amount of combustible material in the area of i

j contaminated materialis the PBRF building roofs. If the tar or urethane i

material of the roof caught fire, structural damage to the building might occur.

Also, the urethane insulation of the CV dome might catch on fire and do structural damage to the CV. Neither type of fire would release a significant amount of radiation because the radioactive material is stored at the bottom of quadrants and canals and is contained in or on the surface of solid materials, generally metallic. It is not credible that a significant part of the radioactive material could be vaporized and carried away.

The overall fire hazard is much less than when the reactor was operating. In the event of a fire, the fire fighters are directed by trained personnel according to station procedures which take into account the possible release of radioactivity.

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The hazards associated with fire are acceptable.

l 18.S Sabotage Hazards due to sabotage are difficult to guard against. However, with the Facility in a protected safe storage condition, the motivation for sabotage is l decreased by the absence of any nuclear fuel. For a saboteur to gain access to l radioactivity, he would be required to break through the NASA Plum Brook

! Station perimeter fence, the reactor site fence, and into one of the PBRF I buildings, unobserved by the station armed security patrol.

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! Since the plant is not operating, neither sabotage nor action by a subversive employee could result in a significant safety hazard. This is because none of the i radioactive material would be readily transportable in large quantities. The high-radiation-level material in the reactor tank and the hot laboratory could j not be removed in a short period of time and there does not seem to be l adequate motivation for such action. The welded shields and shrapnel shields of the reactor tank serve as protection for this material. The presence of security and lack of motivation renders the risks associated with sabotage j acceptable.

18.6 Bombing The only bombing considerations will be for bombs of a non-nuclear type. The

! most serious situation would occur if the reactor tank was demolished and its contents scattered. The debris could be scattered over a large area but would remain within the Plum Brook Station perimeter fence. Since the reactor tank contains solid material, a radiation survey of the Station should allow the recovery of most of the material. A radiation hazard to the public would not exist since it is not credible that any material, other than an extremely small j

amount of airborne activity, would leave the station as the result of bombing.

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l 19. ENGINEERING STUDIES AND EOUIPMENT TRANSFER New information is constantly required to document existing conditions at reactor l

facilities. The PBRF is no exception. Information will be obtained by l

measurements, surveys, borings, tests, and other methods as necessary. This may involve:

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a. Gaining temporary access to controlled areas.

I b. Minor disassembly to obtain access into some equipment or subsystems.

c. Temporary shield removal for accurate measurements.

d. Temporary change to pertinent existing end conditions.

l Items determined by survey to be non-contaminated and not required for protected safe storage may be released for reuse in accordance with approved procedures.

l Some specialty items such as hot windows, manipulators, or experiments handling l equipment known to be contaminated, will upon request, be cleaned to a practical l extent and may be transferred to another licensee, in accordance with 10 CFR Part 30.

I These activities will be procedurally controlled and will require review and

( l l approval of the PBRF engineer and the PBRF Safety Committee to assure that the activity may be accomplished safely, is within the PBRF license requirements and involves no unreviewed safety question.

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20. ENVIRONMENTAL IMPACT The PBRF contains a nonoperable reactor with no fuel, no special nuclear material, no free by-product g'aseous or liquid radioactive material. Major radioactive items i

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i are stored at four locations; in the Containment Vessel, the Reactor Building, the Hot Laboratory and in the Waste Handling Building. As shown in the safety  ;

analysis, these items are confined and protected from unauthorized personnel and water entry. The confinement prevents personnel access to the radioactive material and the protection restricts the spread of contamination. This condition will not  ;

sij;nificantly affect the environment.  ;

An Environmental Report for the Plum Brook Reactor Dismantling was prepared in February 1980. From this,' an NRC-prepared environmental impact appraisal was made available for public inspection at the commission's Public Document Room at 1717 H. Street, N. W., Washington, DC. The Commission concluded an l

l environmental impact statement is not warranted because of a finding of no significant environmental impact attributable to the proposed action. A condition of possess-but-not-operate protected safe storage will have less environmental affect than dismantling. Consequently, there will remain no significant environmental i

impact attributable to this proposed action.

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l AMENDMENT TO LICENSE NO. R-93 i Docket No. 50-185 Qgneral Information l

Pursuant to 10 CFR 50.33, the following information is provided to support the request for an Amendment to License R-93, Docket No. 50-185.

1. Applicant - National Aeronautics and Space Administration l

l 2. Address - Lewis Research Center, Cleveland, OH 44135

3. Class of License- 104; Possess-But-Not-Operate

4. Use of Facility - The facility has no fuel and the reactor is in a pro-tected safe storage condition.

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5. Period of Time for which License is Sought - Twenty years from date of ,

issuance l

l 6. Financial Oualification - Being an agency of the United States' Goveci-I ment, NASA is financially qualified to possess the l requested license.

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NATIONAL AERONAUTICS AND SPACE ADMINISTRATION DOCKET NO. 50-185 PROPOSED AMENDED FACILITY LICENSE i

l Amendment No. 5 License No. R-93 ,

1. The proposed Amendment to facility license No. R-93 should read as follows: )

This license applies to the non-operable heterogeneous light water- I cooled and moderated research reactor [herein referred to as the Mock- l Up Reactor (MUR)] owned by the National Aeronautics and Space i Administration (NASA), an independent agency of the United States Government, and located at the NASA Plum Brook Reactor Facility near Sandusky, Ohio. The MUR is described in the application dated March 15,1961, and amendments thereto, including:

1 AMENDMENT 2 FOR STANDBY: I

Application - March 26,1973 1 Supplement - May 18,1973 l

1 l AMENDMENT 3 FOR PROTECTED SAFE STORAGE:

Application -July 26,1985 l

AMENDMENT 4 FOR CHANGE OF ADMINISTRATIVE OVERSIGHT: 1 Application- February 27,1989 l Supplement -June 22,1989 l AMENDMENT 5 FOR CONTINUED SAFE STORAGE:

Application - November 4,1996 Supplement -This submittal

2. Subject to the conditions and requirements incorporated herein, the Nuclear Regulatory Commission hereby licenses NASA:

(1) Pursuant to Section 104c of the Act and 10 CFR Chapter I, Part 50,

" Licensing of Production and Utilization Facilities", to possess, but not operate the reactor as a utilization facility; and (2) Pursuant to the Act and 10 CFR Chapter I, Part 30, " Licensing of

Byproduct Material," to possess, but not to separate, such byproduct material as may have been produced by operation of the reactor.

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3. This license shall be deemed to contain and be subject to the conditions specified in Part 20, Section 30.34 of Part 30, and Section 50.54 of Part 50, 10 CFR Chapter I, and to all applicable provisions of the Act and to the rules,

, regulations, and orders of the Commission now or hereafter in effect and to l the additional conditions specified below:

l (A) NASA shall not reactivate the MUR without prior approval of the

! Commission; and l

l (B) NASA shall not dismantle or dispose of the MUR without prior approval of the Commission.

4. TechnicalSpecifications The Technical Specifications contained in Appendix A, as revised through Amendment No. 5, are hereby incorporated in this license. The licensee shall possess, but not operate the facility in accordance with the Technical Specifications.

This license is effective as of the date of issuance and shall expire after twenty l years.

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i ATTACHMENT TO LICENSE AMENDMENT NO, 5 l

i FACILITY OPERATING LICENSE NO. R-93 DOCKET NO, 50-185 i

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l Revised Appendix A Technical Specifications in their entirety.

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