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IPRELIMIfiARY-

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR MATERIAL

SAFETY AND SAFEGUARDS

GEtiERAL ELECTRIC COMPANY

SPECIAL NUCLEAR l%TERIAL

LICEtiSE NO. SNM-960

DOCKET fl0. 70-754

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I.INTRODUCTION

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On October 20, 1977,General Electric reported to NRC that its geo-

logical consultants had found evidence of a low angl'

e thrust fault.This evidence is believed to be associated with the Verona fault whichhas been recently mapped within about 200 feet of thTest Reactor (GETR). e General Electric

The significance of this evidence, if correctthat the tectonic setting of the VNC*must be consid

is,

ered active, thepotential ground accelerations at the site would be sig ifi*

n cantlygreater than was previously thought to be the case

, and that offsets ofthe ground surface, or surface faulting

, could be expected to occur atthe site in the event of a seismic event.

Since that time, NRC has issued an Order to Show Cause in the matter ofGETR Operating License No. TR-1 ordering that on O t b

c o er 27, 1977, theGETR be placed and maintained safely in a cold shut d

own conditionuntil GE can show cause why the activities under that lice

nse shouldcontinue.

Also noted in the Order to Show Cause was GE's committhat by October 28, 1977, it would provide t

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o the NRC staff an assessws.

ment of all NRC-licensed activities at the VNC siteThis assessmentwas provided by representatives of GE on Friday and Sat

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urday, October 28and 29, 1977,,in an oral and slide presentation to th'

j, information presented will be confir e NRC staff. All the

med by GE in writing.assessment, NRC/NMSS performed an independent assessmentIn addition to GE's

of activitiescovered under Special Nuclear Materials License No

SNM-960. This.

* VNC - Valletitos Nuclear Center.

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safety evaluation is based on the information presented orally at the

meetings and an independent staff analysis.,

Purpose and Scope

The purpose of this analysis is to obtain a preliminary assessment of

the potential off-site radiological consequences of a major seismic event

affecting the site in light of new information concerning faults in or

near the site. This analysis is directed to special nuclear material'

authorized by NRC License No. SN!i-960; it also. covers byproduct materials

located in the same areas at VNC authorized by California State License

No. 0017-59. Materials under these licenses are located in a number of

buildings throughout the facility for a variety of purposes. In most

instances the quantities of materials actually at VNC are either small

or in a physical form or otherwise contained in a way which makes.signi-

ficant dispersal very unlikely following a seismic event. The staff has

surveyed all buildings to determine the status of use and storage under

the materials licenses but has concentrated its detailed analysis on

| Building 102 where significant quantities of materials might be available,

for dispersal. The~immediate decision about continued activities under

the materials licenses centers on the off-site radiological consequences of a

seismic event affecting Building 1.02. If these consequences are small, the.,

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| added contribution of radiation from other buildings would not be enough to tip

the balance of that decision. For purposes of this safety evaluation the staff

based its review on conservative simplifying assugtions. We feel that such

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conservatism yields offsite doses that are higher than would be the

case if more accurate bases were used. However, it was judged that ,

acquisition of data necessary to support more accurate bases would

require a prohibitive span of time and precision was sacrificed to,

timeliness.

Background

New Information~

In mid-July 1977, the NRC staff . initiated a review of the geology and

seismology of the Vallecitos site. A brief review of the updated

information provided in support of the application indicated that

difficult seismologic and geologic questions existed at the site and

that there was insufficient information concerning the seismic and

geologic characteristics of the area at VNC. The NRC staff's concerns

were discussed with the licensee in August 1977, and the NRC staff

indicated that additional geological and seismological information

would be required. At that time, the NRC staff learned of a recently

completed U.S. Geolo:ical Survey investigation of tt, region which,

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includes VNC..

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.the NRC staff received, a. ..

' Subsequently, on August 22, 1977,*

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copy of the USGS open-file report, Number 77-689, which contained an

interpretation of the geology of Livermore Valley, California. A new

geologic map which accompanied this report indicated that the Verona

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fault, previously mapped approximately 1/2 mile north of GETR, came4

within about 200 feet of GETR.

To obtain more information regarding the nature of the Verona fault, a

trench was dug by the licensee and inspected the week of October 10,'

1977. Members of the NRC staff, accompanied by a member of the USGS,

inspected the trench on October 13, 1977. Although direct evidence of

faulting could not be, observed at that time, the possibility of thrust

faulting could not be discounted. Accordingly, the NRC staff requested~

that the trench be allowed to dry out, that it be deepened at one end,

and that the walls be cleaned up and thoroughly mapped to confirm that

there was no evidence of the existence of the fault. This work, and

completion of a second trench, was carried out by the licensee. On

October 20, a representative of the licensee, in a telephone conver-

sation with the NRC staff, reported that its geological consultants had

identified evidence of faulting in both trenches. A staff geologist

and seismologist and a representative of USGS visited the site on.

October 22 to observe and evaluate the geologic characteristics in the

trenches. Existence of the fault and evidence that it might be " capable,"-'

as that term is used in,10 CFR P, art 100, were confirmed during our ,

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October 22 investigation. The significance of this new information is

presented below.

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Geological and Seismological Sianificance'

The VNC s'te is located in the Livermore Valley. Geologically, the '

site is within the Livermore Syncline and is approximately 7,500 feet

from the nearest splay of the Calaveras fault. The trace of the Verona

fault as postulated by the USGS (USGS Open-File Report Number 77-689)

crosses the VNC site. The Las Positas fault, if projected to the

southwest, passes within about 10,000 feet of the site.. .

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The Livermore syncline, the Verona fault, and the las Positas fault

must, on the basis of current information, be considered to be genetically

related to movement on the Calaveras fault. The Calaveras fault is a

major strand of the San Andreas fault system. Movement on the San

Andreas and associated faults is occurring at about six cm per year.

The tectonic setting of the site must be considered to be active. The

Calaveras fault is known to be moving in a right lateral strike slip

direction which results in the rock mass west of the fault being moved

| northward relative-to the rock mass on the east side of the fault. The*

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| rate of movement across this fault zone can be measured in millimeters' per year. The Verona fault trends approximately northwest-southeast

a$d at an angle to the northwest trending Calaveras fault. The fault*

dips (apparently to the north) at a low angle. Movement on the Verona

fault is of a thrust nature with the northern block being relatively|| thrust over the block to the south. On the basis of current information,!

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this fault must be considered to be genetically related to the Calaverasi

fault. The genetic relationship of the Verona fault to the known

active Calaveras fault, the close proximity of the Verona fault to the

Calaveras fault, and the evidence revealed by the October 20-22 investi-

gations lead us to conclude that the Verona fault should be considered

to be capable,

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Vibratory ground motion at the site will likely be controlled by movement'

on either the Verona fault, on the -Calaveras fault', or on both. The~

14RC staff's assessment of the earthquake potential of the Calaveras

fault, based on currently available data, leads it to conclude that the

most severe earthquake associated with the fault would be in the magnitude

range of 7 to 7.5. An earthquake of lesser magnitude, perhaps 6 to

Based on these consider-6.5, would be associated with the Verona fault.

ations, either the Calaveras or the Verona fault would be capable of~

producing ground motions at the site with accelerations of sustained

duration in excess of .75g if the earthquake were to be centered along

the sectors of the fault nearest the Vi4C facilities.-

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Of particular significance in this situation is the fact that an earth-I

f quake of this magnitude would be expected to produce offsets of the'

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| ground surface, or surface faul+1ng. Given the close proximity of the

i Verona fault to the Calaveras fault, movement on the Verona fault

simultaneous with movement on the Calaveras fault would be expected to

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II. FACILITY DESCRIPTION

A description of the various facilities covered under these licensese

follows:,

A. Radioactive Materials Laboratory

The Radioactive Materials Laboratory (RML) is located in Building

102. This laboratory is a shielded facility equipped with remote

manipulators to conduct experiments and analyses with irradiated~

reactor fuels and other radioactive materials generated in Vallecitos

reactors or received from customers and to separate specific

radionuclides. No fuel is reprocessed at the VNC facilities. The

facility also includes a storage pool and dry pit storage.

B. Radiochemistry Laboratory.

Adjacent to RML, on the main floor of Building 102, and providing

analytical support to it, is a radiochemistry laboratory equipped

with standard ~ chemical and radiochemical apparatus. This laboratory

is primarily used to analyze samples of materials prepared in the.

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| C. Plutonium Analytical Laboratory; -

| Located also on the main floor adjacent to the radiochemistry

laboratory is an analytical laboratory providing support for the

| Advanced Fuels Laboratory.

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D. - Advanced Fuels Laboratory (AFL)

located in the basement of Building 102, the AFL is equipped with .

glove boxes, fume hoods, and other apparatus appropriate to the

development of clad fuel elements and materials and property

studies on compounds of plutonium and uranium, scrap recovery, and

nitrate conversion.;

E. Meta 11uray, Chemistry, and Ceramics Building *

* A second major laboratory building in the 100 Area is the Metallurgy,-

Chemistry, and Ceramics Laboratory--Building 103. This two-story

building consists of offices and laboratories, variously equipped

with laboratory apparatus designed to handle small quantities of

radioactive materials, and offices. The functions served by this

facility are research, development, and analytical chemistry

services.-

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F. Buildino 105

Just north of, Building 102 is Building 105. The principal facilities.

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located in this building are a research reactor (the Nuclear

Test Reactor), two special nuclear material storage vaults for'

special , nuclear material, and laboratories. The Nuclear Test-

Reactor serves as a source of neutrons for exponential experiments,

irradiations, and as a device for reactivity measurements. At

infrequent intervals, the laboratories in Building 105 contain

small quantities of clad special nuclear material. ',

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G. Maintenance and Development Shop

Building 106 contains maintenance shops, instrument calibration ;

f acilities, and the development shop. Special nuclear materials

,are brought to the development shop as encapsulated devices for

equipment or mechanical modification and for radiography.

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H. Irradiated Fuel Storace Facility

A pool fuel storage facility is situated adjacent to the deactivated

Vallecitos Boiling Water Reactor (VBWR). This facility is designed' '*

as a storage basin for irradiated fuel elements and assemblies and

for the modification, inspection, and decontamination of reactor

This facility has not been used for itsfuel and components.

designed purpose or fuel storage and has been empty of fuel for*

the past five years.

Solid Radioactive Waste Storage Facility.

1.

Solid radioactive wastes generated at the various laboratory and

facility locations are stored in the waste storage facility located*

approximately midway between the VBWR and General Electric TestThis storage area includes vertical wells

Reactor (GETR) areas.. ,

for storing drummed wastes and horizontal tubes for storing five-.

inch diameter waste liners.

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J. Vaste Treatment Plant

The Waste Treatment Plant is located adjacent to the dcoctivated ;

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VBWR site. This plant is used to concentrate and solidify liquid

radioactive wastes generated at the Vallecitos Nuclear Center

prior to transfer to authorized waste disposal firms or waste

burial sites. Such wastes contain only small quantities of radio-

active material.i

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K. 400 Area

The 400 area consists of two buildings, 400 and 401. Building 401

is chiefly devoted to offices while Building 400 contains an

experimental low-enrichment uranium scrap recovery system and some-

byproduct facilities licensed by the State of California.

L. Buildina 104

This building includes warehousing and shipping and receiving

facilities.

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III. Materials at R'isk*

One of the bases for determining the consequences of accident is an

estimate of the amount of hazardous material that may be released -

during the catastrophic event. Material at risk is material that is in

a location and condition such that it is available for release in the

event of breach of confinement. In our assessment we have not used

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the upper limit of licensed possession as the amount of any

radionuclide that is available for release. The facility will rarely, *

if ever, hold the upper limit authorized and much of the material

possessed is encapsulated and/or held in protective storage and thus is

not available for dispersion. The amount of material in process or

ready for process is generally, but not necessarily, the amount at risk

for any radionuclide. In order to assess the quantities of material at

risk the amounts in process as well as total inventories were estimated.

by the staff by' onsite examination of the Radio' active Materials Laboratory,'

the Advanced Fuel Laboratory, and other locations of radionuclides

onsite. .

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The isotopic composition of any plutonium involved was provided by GE

as: Pu-238, 0.053 w/o; Pu-239, 86.5 w/o; Pu-240, 11.8 w/o; Pu-241,

1.4 w/o; and Pu-242, 0.2 w/o. The staff has used these values for its,

calculations.

A. Radioactive Materials Laboratory.,

The Radioactive Materials Laboratory (RML), on the ground floor of

Building 102, is the site of hot cell operations,where most of the* byproduct materials are processed, being' dissolved, separated, and

converted to their final product form or waste form. The process

inventories or total inventories were provided by the General

Electric Company (GE); these were based on their operating experience

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and actual measurements in the facility. The NRC staff reviewed

the GE estimates, particularly with respect to radionuclides that '

could be significant contributors to offsite doses. The inventories

estimated by GE are essentially cell contamination levels, (with.

the exception of Kr-85) a portion of which are available as resus-

pended aerosol for release in the event of breach of confinement,

and radionuclides that are contained in fuel rods or elements that

are being analyzed or held in storage. Because these materials.

exist as so10tions or solids they are available for airborne dispersion

only in relatively small quantities through aerosol formation or

resuspension phenomena. The potential for waterborne dispersion is

discussed below. Nonetheless, the staff made the conservative assumption

that the total isotope inventory in a cell was available as liquid or

surface contamination for dispersion as an aerosol. Cell 3 has not been

analyzed by the staff because it is used to recovery medical isotopes,

generated in the GE Test Reactor fuel, this reactor has been shut 'down.

Thus the noble gases, halogens, mixed fission product particulates, and

actinides associated with that activity are no longer being produced and-

were thus not considered in this analysis. GE has agreed that these

activities will not be resumed without prior NRC approval.. .

B. Advanced fuels Laboratory

The Advanced Fuels Laboratory (AFL) is located in the basement

area of Building 102. On an October 26 site visit, a detailed

examination of each individual batch or unit operation was made by'

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the staff to determine where available material at risk could be

in process at the time of a severe seismic event. Although pluto-

nium nitrate solution would not normally be characterized as a

material at risk, the staff has hypothesized that if the solution

were spilled it could dry with sufficient time and become a,

source of plutonium for release. As a result of the examination

of the AFL processing facilities two operations were considered

candidates for evaluation to determine release of plutonium from

the basement area. These are the (1) ceramic line powder blending

and hammer milling and (2) nitrate conversion.

In the powder blending and hammer milling operation, Pu0 and 00-2 2

or a coprecipitated mixture of Pu0 - U0 are processed. The2 2,

materials are kept in sealed cans until operation is to commence.

During the short time the hammermill is operated, oxide powder is!

not totally contained within secondary confinement. While blended,

however, it is scaled. During discharge of the blender, the

powder is again not in a sealed container. Although the time of-

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powder availability for release because of potential rupture to.

the glove box is short, this operation contains the largest quantity,

of Pu02 p wder and is used f'or the accident analysis. No other'

operations have Pu0 Present in undiluted form or in the quantity2

used in this operation.|

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In the nitrate conversion process, plutonium nitrate solution is;

introduced from a storage container into a glove box for sub-

sequent processing. It is at this location that the maximum*

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amount of solution containing plutonium would be available to

spill on the floor..

These two process' units are considered in Chapter IV, Accident,

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/C. Plutonium Analytical Laboratory

Ananalytical laboratory is located on the first floor of Building

102. This laboratory is primarily devoted to analysis of plutonium

solutions and compounds. Although the quantity of material located

in this laboratory is relatively small, its vulnerability to a

seismic event is sufficient to include it in our consideration of

release of plutonium to the environment. We are including both

plutonium oxide powder and plutonium nitrate in our seismic event"

analysis. '. .

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D. 0ther Structures ,,

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GE has i'dentified other structures and locations which could

contain radioactive material. A tabulation of these locations and

the type and form of the material is shown in Table III-1.[ These\' -

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TABLE III - 1LOCATIONS OF RADI0 ACTIVE MATERIALS :

NOT AT RISK

LOCATION COMMENT

Building 103 - Metallurgy QA Check of Encapsulated sources;& Chemistry < 100 pCi Radioactive Material in

Analysis

Building 104 - Warehousing, Shipping, Material in Approved ShippingReceiving Containers

Building 105 - Advance Nuclear Fresh GETR Fuel; Sealed andApplications Encapsulated Pu-

Building 106 - Shop Operations Small Numbers of EncapsulatedDevices for Modification orRadiography

300 - Fuel Storage Pool Not in Use

103A Cobalt Pit Double Encapsulated Cc-60

Irradiated 'uel SpecimensFSolid Radioactive WasteStorage Facility and Structural Components

Stored in Metal Containers~

Waste Treatment Plant 10 3 pCi/M1 Water Processed toyield 10 7 pCi/H1; ContaminatedWater Solidified

Building 400 - Metallurgy Low Enriched Uranium ScrapDevelopment Recovery; Xe ampules (medical*

quantities) storage*

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materials do not offer potential for significant release because

of their form and confinement. A catastrophic event affecting these

structures would be expected to contribute only a very small

fraction of the total dose from Building 102.

E. Other Considerations

In the course of this evaluation the staff has considered potential

secondary effects from a severe earthquake as well as from other~

potential accidents. Specifically dealing with the latter point,,

the staff examined the possibility of a criticality event.

Although no specific mechanism could be identified by the staff,

the staff has conservatively assumed a criticality event to assess

the relative offsite impacts. These results are presented in the

following chapter.

Potential secondary effects including fires, explosions and flooding,

were considered by the staff since these events may represent

means by whic,h material can become mobilized. The absence of.

appreciable quantities of flammable material lessens the potential

! for fires. This has been verified independently by the staff.'

Consequently, heat sources, such as electrical short circuits, are*

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not likely to result in severe fires. GE has agreed that no

additional quantities of flammable materials shall be used or

stored in these areas without prior NRC approval.|

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The licensee did state that 6 percent pre-mixed hydrogen / inert gas

is stored onsite outside Building 102 and is made available through'~

a piping system to the AFL for use in the sintering process.

Alsa, a limited quantity of quenching gas is present. The licensee

does not consider these gases as explosive mixtures. The staff

agrees. The licensee stated that no explosive mixtures are stored

in the RML and AFL. Therefore the staff did not assume this as a-- - - _ _ _ . . _... , _ .

credible mechanism for dispersing plutonium. GE has agreed that' ~

no such materials shall be' used or stored in these areas without

prior NRC approval.~ ~- . . . ,

Flooding has been expressed as a concern because of the potential

for contamination of water supplies. Therefore, the staff has

examined sources of water which could impact the plutonium facilities.

A small on-site man-made lake is located approximately 1,000 feet

from Building 102. The licensee has stated that there are 7 acre-

feet (300,000 cubic feet) of water impounded behind an earthen

embankment. The spillway on the embankment is diverted to a ditch.

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which passes near to Building 102 and discharges into a creek. In

1967 the licensee modified the drainage path and lowered the level

of the lake to minimize the potential for. flooding due to failure.

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of the embankment. Therefore, the licensee claims that the lessened

inventory of water and larger drainage ditches will divert flow

away from on-site structures. Based on the available information

the staff believes the failure of the retention dam.during an

earthquake is highly possible. If the dam fails, it is the staff-

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Judgment that a small percentage of the water could enter the AFL.

The likelihood is however relatively small. More rigorous analyses

are being conducted to confirm this judgment. The potential off-,

site consequences of such an occurrence are limited. Even assumingt the wal1s of the AFL are cracked, it is doubtful that the

plutonium could get offsite. The AFL floor level is twelve feet

below grade and the radic-hemical characteristics of the plutonium

and the soil around all the buildings are such that the soil should

retain any radionuclide out-leakage. Notwitstanding the remote likelihood

of plutonium, getting into any adjacent streams by whatever cause, the .

radiochemical characteristics of the plutonium and the stream

channel soils are such that transport of matarial over long.

distances is very unlikely. The possibility of ' surface faulting

could create new stream channels and therefore may introduce greater

transport capability; however, the soil would still have the same

characteristics as the present stream channels with respect to

nuclide uptake. Nevertheless, it is the staff's conclusion that -

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until a detailed analysis is satisfactorily completed the lake~

should be drained to reduce any conceivable hazard to public health,

and safety due to flooding. .

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the event,of a seismic event such pipes may rupture and discharge-

sufficient water at the break to cause concern due to runoff.

; However, the staff does not believe that there is an immediate

hazard frcm such water sources because the entrance to Building

102 is about 18 inches above grade level. Additional study as to

pot'ential failures in such on-site pipelines will be conducted toi

confirm the staff judgment..

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Within Building 102, but beyond the AFL, there is a storage tank

containing 12,600 gallons of water. Due to the construction of

the building, the tank is located on dirt fill. Seismic failure,

of the tank would release water. However, the tank is enclosed

within a concrete vault and any spillage would have to penetrate.

the, vault, soil and the wall of the AFL in order to enter the AFL.

An automatic water fire suppression system is located in the AFL..

Although not in operation at this time, the licensee intends to

make the system operational in the near future. In the event o.f a'

pipe rupture, the water will collect on the b,asement floor. There.

are no drains from the AFL. Any water collecting in the AFL

is diverted to several sumps in the floor. There are no drain or

pipe connections to or from these sumps. The combined capacity of

these is about 11,200 gallons. Portable pumps are used to keep

the sumps dry in the event of water buildup. However, in the

event of a severe earthquake the staff believes that water may be"

' postulated to enter the AFL but the quantity will be limited. For

example, the supply lines for the water fire-suppression system

most probably will also rupture thereby limiting the available,

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quantity of water.(

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gallon) water storage tank. Based on the local topography and

location of the tank, the staff finds that there are no mechanisms

to concentrate the flow of the spilled water such that it will

constitute a threat to the plutonium facilities.,. .

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IV. ACCIDENT ANALYSIS

(The licensee has provided the staff with the results of structural

analyses or reviews of facilities of interest to support its determina-

tion of ource term. Notwithstanding the postulated structural responses

providcJ by the licensee, the staff developed scenarios and made simplify-

ing assumptions that imposed more catastrophic effects upon the facilities.

Based on these, source terms were derived for use in the calculation of.

radiological consequences.-

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A. Radioactive Materials Laboratory. .

The four main hot cells that make up a portion of the RML arei

relatively compact, massive structures with 2-3 feet thick walls,

constructed of high density concrete. The cells that handle mixed;

fission products and alph' emitting elements also have an innera

cell that is a 3/16-inch thick, free-standing, stainless steel

liner. The licensee assumed that the hot cell structure would*

renain intact in the seismic event, that in-cell liners with their

captive HEPA and charcoal filters would remain intact, as would,

process equipment that is attached to cell walls., GE did . assume.

that ventilation duct work leading from the cells would be lost

and the cells would vent to the ambient atmosphere. GE further

assumed collapse of first floor walls and loss of all power. Fire

was assuT.ed not to occur in the cells because the only flammable

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material in the cells is a small amount of heavy solvent used in<

the fission product separations process.

The staff is not able to confirm the licensee's evaluation of

structural response of the several areas of concern in the RML

including hot cells since the numerical analysis was not provided.-

The staff assumed that the first floor structures in the RML,

collapsed, that interconnecting ductwork and utilities were torn. .

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away, and that cells were tipped and breached. In-cell liners

were assumed to remain intact but filters were compromised by

puncture.

The licensee provided total inventories of all isotopes associated

with each cell as well as release inventories. The listing consi-

dered over forty radioisotopes that have been determined to reside

in the cells. The release inventories provided by GE were supplied,

['

as simple quantities with no address to duration of release or.

release rate." .As a conservative measure the staff calculated off-i

site dose from that release inventory considered to enter the.

. ambient atmosphere as a puff. The isotopes of concern to off-site,

, ,

dose wer'e found by the staff to be Ce-144, Cs-137, total a as Pu-

239 and Tc-99. Total and release inventories for the isotopes of

concern are as follows:

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- 23 -

Isotope Total Inventory (Ci) Release Inventory (uCi)Ce-144 180 18,000

'

Cs-137 383 38,300Total a as Pu-239 16 1.6

Tc-99 2200 22

As a check on the calculations that assumed puff release, the

staff calculated release rates of isotopes as a function of he.

'

total invdntory using its own scenario for structural response.

These calculations assumed that all radioisotopes present would be

presented to the cell atmosphere as deposited material with a

resuspension factor of 10-6 ,-1 and that the cells " breathed"

through the cracks such that 0.1 cell volume per hour was exchanged

to the ambient atmosphere. Based on the staff's check calculations

the tabulated inventories shown above, released as a puff, provide

conservative estimates of source term.

*.

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B. Advanced Fuel Laboratory *

As discussed in the section identifying material at risk we have'

e ,*

selected the blending and ham'mermilling glove box for an accident{}analysis. It is the only operation where undiluted Pu0 would be l

2

available in unsealed condition. GE has conducted analyses regarding

the structural integrity of the AFL and their results indicate.

that structural integrity will be maintained.

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- 24 -

Nevertheless, the staff has assumed that the building structure

loses its integrity as a result of a seismic event. Cracks develop

in the walls and ceiling, and building internals are damaged.Itwas assumed that the glove boxes will not remain fixed and will

lose their leak-tight integrity. This scenario results in thepotential for release of pug1

2 Powder from the glovebox to the roomand subsequently to the environment.

.

In order to determine the quantity of Pu02 released the followingi assumptions were made:

* the Pu0 is not sealed in the blender or in a storage can2

* the glove box volume is two (2) cubic meters (m )3.

* the air within the box,is loaded to 300 mg/m3

* based on particle size distribution, particles of 10 microns

(p) AMD*or greater will constitute about 90% of the mixture,

|.

.

* particles less than 10 pMt0 are assumed available to leave

the room. (60 mg)i

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.

* one-half of the 60 mg in the room reaches the ceiling and|

escapes from the building

.

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* therefore 30 mg Pu0 is used as the source term.in the radio-2

ilogical analysis.

For the plutonium nitrate solution spill, the following assumptions.

were made:

* a storage container or nitrate conversion equipment topples

and/or is broken to spill its contents (2 kg Pu as plutonium

nitrate) on the floor. . .

* release fraction to the room: 1 x 10-8/sec

* 0.1% air exchange thru the building

* The release rate of Pu is 0.02 pCi/sec which is used for the

source term.

C. Plutonium Analytical Laboratory

=.

.

The analytical laboratory is one of the facilities located on the.

first floor of Building 102. As indicated in Section A. above,,

the staff assumed that the first floor structures collapsed and as

a consequence glove boxes were overturned and crushe'd by falling

debris. Both plutonium powder and nitrate are assumed present.

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26 --

Releases of plutonium from the Analytical Laboratory due to struc-

tural failure are predicated upon the following assumptions:.

flitrate

* a glove box is crushed by falling walls and debris spilling

the normal inventory of 100 g. of Pu as nitrate onto the floor;

* release fraction to room from floor 1 x 10,8/sec;~

- -,.

* 10% air exchange thru debris to ambient atmosphere;

* the release rate of Pu is 0.1 pG/see to the ambient environment

.

Powder

* a glove box is crushed by falling walls and debris spilling the.

normal inventory of 6 g of Pu as pug nto the floor;2

* 10% of the particles available for suspension as particles of

AMD less than 10p..

*-

.

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* release fraction to room 6 x 10 /sec;

* 10% air exchange through debris to ambient atmosphere;

.

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* The release rate of Pu is 3.6 x 10'3 pg/sec to the ambient4

environment.

D. Other Structures

The licensee also conducted structural analysis of Building 105.

Plutonium is stored in a vault within this structure. Based on

the results of his analyses, the licensee also claims that the.

vault structure will remain intact. However, since the material. .

is' stored in a form which is not readily dispersable and is in

sealed containers, the staff does not believe that it constitutes

material at risk for purposes of this report.

i V. RADIOLOGICAL CONSEQUENCES

Methodolooy

The radiological consequences were estimated for the postulated earthquake

with its upperbound effect on the various structures of concern. The.

release scenarios describing the transport mechanisms with the related

assumptions and the source terms quantified were developed in the.

accident analysis'section. Table V-1 summarizes the controlling source

terms developed from each scenario.

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28 --

.

SUMMARY OF THE CONTROLLING SOURCE TERMSFOR THE POSTULATED RELEASE MECHANISMS 1

Location and Release Type Ouantity Released Release Rate

Advance Fuels Laboratory.

Plutonium Oxide Release 2.6 x 10 2g Pu InstantaneousPlutonium Nitrate Release 2.4 x 10 29 Pu 2 x 10'8g Pu out/sec

11 x 10 8 Fissions InstantaneousCriticality Incident

Plutonium Analytical Laboratory. _

Plutonium 0xide Release 3.81 x 10_3g Pu 3.6 x 10_SgPuout/segPlutonium Nitrate Release 1.20 x 10 lg Pu 1.0 x 10 7g Pu out/see

,

Radioactive Materials Laboratory--

Hot Cells Contamination Release Ce-141 1.8 x 104 pCi InstantaneousCs-137 3.8 x 104 pCiTc-99 2.2 x 101 pCiAlpha 1.6 pCi

Building 102 houses the Advance Fuels Laboratory, Plutonium Analytical

Laboratory, and the Radioactive Materials Laboratory, all of which were' quantitatively evaluated for potential releases. 'Three distances from

Building 102 were selected. .They are as follows:

(1) 440 meters - the minimum distance from Building 102 to the

site boundary;

(2) 750 mete,rs - the nearest off-site residence;i .

1 '

(3) 5,000 meters - the nearest town..

The staff assumed that the released material would be'airbornd for the,

duration of the transit to the point where the dose is calculated. The

points considered were assumed to be on the centerline of the plume for

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- 29 -

either a puff release or a continuous release. For a puff release, an'individual was assumed to be fixed at the selected points for the

duration of the release. For a continuous release, an individual was

assumed to be at the site boundary for a period of two hours and for

the other two points,a 24 hour period was assumed. The inhalation rate-4assumed for an individual fixed at the points considered was 2.3 x 10

3m /sec. No credit was assumed for settling or agglomeration of the

aerosol during the transit. The transit time was assumed to be instan-.

taneous. The above assumptions giv'e,- the'upperbound estimate of the'

gases and/or particulate concentration for the meteorological conditions

used.

Two meteorological dispersion schemes were used in the consequence

calculations. The realistic meteorological condition for the site was

taken as 50% meteorology; a 5% meteorology was used in the conservativei

estimate. This translates into a factor of at least 10 conservatism in the dose

f calculated using the 5% meteorology as compared to the 50% meteorology.

.

For the conservative dose calculation, the 5% meteorological conditions,

!

used are described in Regulatory Guide 1.3, " Assumptions Used for.

Evaluating the Potential Radiological ~ Consequences of a loss of Coolant

Accident for Boiling Water Reactors." The atmospheric conditions for

the release were Pasquil Type F with a windspeed of 1 meter /sec.,

uniform in direction. For the 24 hour ground level release, the samee

.

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type of atmospheric conditions were used except that the plume was4

assumed to meander and spread uniformly over a 22.5* sector. Due to

the limited onsite information that is available, the Regulatory Guide

assumptions may not be sufficiently conservative. More detailed onsite

transport and deposition studies are likely to offset this deficiency so

that dose estimates would not be substantially different..

.

Results

Thesummaryofthedoseconsequ'encesfortheskxreleasemechanismsare

presented in Table V-2. The results presented are based on the 5%,

meteorology. More realistic results are obtained by using the

average meteorology; therefore, the results presented can be

lowered by a factor of ten (10) to obtain a better estimate of realistic

results.

VI. CONCLUSIONS

As noted in the previous section, the staff has conducted scoping*

analyses to assess ~ the likelihood of release of radioactive materials

to the environment. The source terms derived from these analyses are

mechanistically derived and are intended to represent a limiting release, ,

from the VNC' facilities assuming a continuation of certain activities

similar to those conducted in the past. The objective of this report

is to ascertain the potential hazard associated with postulated events

which may result if an earthquake, producing offsets of.the ground

surface, or surface faulting, were to occur.

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TABLE V-2-

SUMMARY OF DOSE CONSEQUENCES (REM)*,

;'

Source 440 m 750 m 5000 m-

,

Whole Elio~le WholeoThyroid Body Bone Lung Body _ . Bone Lung Body Bone Lung,

_

AFL', (Pu0 ) 5x10-2 1.0 7x10-I 2x10-2 4x10-I -I 1x10-3 2x10-2 2x10-22 3x10

AFL

(PuNitrate) 7.5x10-4 1.6x10-2 3.8x10-4 1.4x10-3 2.9x10-2 6.8x10-4 4.2x10-5 8.9x10-4 2.1x10-5.

'' Analytical.

-

' Laboratory| (Pu0 ) 6x10-5 7. 3x10-4 6.1x10-4 1.1x10'4 1.3x10-3 1.1x10-3 3.3x10-6 4x10-5 3.4x10-5

*

2:

| AnalyticalLaboratory(PuNitrate) 3.8x10-3 8x10-2 1.9X10-3 7x10-3 1.5x10-I 3.4x10-3 2.1x10-4 4.4x10-3E2.1x10-4

i

AFL,

(Criticalityincident) 4.0 1.6 - - - - - - - -..

, , ,

RML 7.6x10-2 1.1x10-I 2.5x10-2 2.9x10-2 4.3x10-2 9.7x10-3 1.7x1073 2.6x10-3 5.8x10-4 .

TOTAL (REM) 4.0 1.73 1.2 7.3x10-I 5.8x10-2 6.2x10-I 3.1x10-I 3x10-3 2.8x10-2 2.1x10-2-

.

EBased on Regulatory Guide 1.3 Meteorology. .-

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- 32 -

The suitability of proposed sites for power reactors is evaluatad in

accordance with 10 CFR Part 100. The dose guidelines used to evaluate

the consequences of a major reactor accident are specified in 10 CFR,

Part 100 as 300 REM thyroid and 25 REM whole body. The staff practice

in the past regarding plutonium-fueled reactors has been to specify

additional guidelines for plutonium of 75 REM lung and 150 REM bone.

The lung and bone dose guidelines, which are not specifically addressed

in 10 CFR Part 100, are the equivalent organ dose, corresponding to a.

whole body dose of 25 REM. With regard to plutonium facilities, such

as VNC, no such definitive criteria exist. Therefore, the staff has

chosen these guideline values as a reference point for assessing the

potential magnitude of such a condition. The siting criteria for power

reactors also considers other variables, such as proximity to large

population centers. It is not the staff's intent herein to assess the

long-term suitability of the VNC site; however, ::taff believes that

these dose values provide a basis for judging the immediate situation.

The decision to take immediate action or to rursue the matter in a more

timely fashion is . based on the results of the radiological analyses..

On the basis of the staff's preliminary analyses, we conclude that no'

immediate act,fon is required at this time with respect to activities*

conducted under NRC License SNM-960. The staff finds that draining.

of the on-site lake should be conducted as a precautionary measure;

GE has agreed to do so.

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- 33 -

.

Some of the information used by the staff in this evaluation was presented-

tby GE in discussions with the NRC staff. To the extent possible, the

staff has conducted its own analysis as a basis for its conclusions

relative to the safety of these VNC facilities. All the information:*

presented by GE must be formally submitted in writing.

Based on the calculated dose consequences, the staff finds that thei

dos'es from the assumed seismic event are a small fraction of the afore-- - . . . .

mentioned guideline values. The doses at 440 meters are of about the

same magnitude allowed by 10 CFR Part 20 annual exposures for occupa-

tional workers on a routine basis. Consequently, the staff does not

find a compelling reason to suspend the NRC license or to suggest other

parallel action by the State of California with respect to its licensed

activities.

'

This preliminary analysis is predicated on the modes and types of

operation experienced by GE in the recent past. Based on these operations,

the material at risk was 'dentified. Different programs can involve*

,

! materials, processes and quantities not considered in this analysis.,

The licensee will prepare a safety evaluation, for staff review and. '

*. . .

approval prior to implementing any change which may affect the|

foregoing considerations or increase the material at risk.i

.

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34 --

The NRC staff has recently initiated a detailed analysis of natural.

phenomena effects on the VNC site in connection with GE's application

for renewal of its special nuclear material license. The review will

provide a realistic risk assessment of the range of credible consequences

of natural phcnomena and the likelihood thereof. k'e consider that a final

resolution can be achieved in this manner without posing an immediate

undue risk to the public health and safety.~

.

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