ML19207A451
| ML19207A451 | |
| Person / Time | |
|---|---|
| Site: | 07000572 |
| Issue date: | 03/01/1971 |
| From: | Cave W MONSANTO CO. |
| To: | Desiree Davis US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML19207A429 | List: |
| References | |
| NUDOCS 7908170572 | |
| Download: ML19207A451 (24) | |
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MONSANTO RESE ARCH CORn #s4se for sie U. 3 Aioenic ta.rgy re P. O tos ?2 PORATICr4 oa mess on uiamistveg. Cheo 45342 Ph o n e- (5131 8 66 -74 a 4 DU T P.'
M RCr.ED March 1, 1971 p
Mr. D. D. Davis, Area Mana Dayton Area Office ger Post Office Box 66U. S. Atomic Energy Cc=nic i s on Minnisburg, Ohio 45342 Attention Mr. E. A. Walke r
Dear Mr. ' Davis t Pursuant to as a tentative plan for scrplirecent discussions uith you destructively analyzing pl ng, en 2ining, and, in so, the following is utonius c* or:yllium neutron so sub=i by variouAt the present ti=e ther ne cases,tted urces.
These sources were manufauniversitics, industriese are 1,500 to 2 Corporation - Mound Lab n sources in oratory,1:ancanto Researchctured pr Dayton Lcboratory, and UC'E use range in C, Apollo nto Resecrc sources,ated pluconium-239-boryllit:nsi o from appr encaps el.
rd curie to ten curica ofThe:c particularly those canufact more than eight years cc= pound.
Most of these in the early 1Since the recanning progr ured by Mound Laboratory old.
are Ucueron Source:960 's (ref. "Inspectionam which uns conducted by Mound L attempt has been, cada to" MDI-1183, M. R. Hert and Rccanning Progrc=aboratory field themse,lves, which consiother than the cursory inspe tievaluate t of Puse checks.
c urce.2 in the of them should be rcesliedBecause of the age cf thecst of per and radiographic inspection ccc e ccurces a alpha vipe and subjected to dimensionalrepresentative cc=ple the sources.
to In addition, a crall sceple destructively analyzed to d evaluate the continuing integ iIcah check, pressure increase with tira of the sources r ty of eternine fuel /catal cc=patibi should be lity and a subs.o.a ry of Monsanto Comp i c,
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V Mr. D. D. Dav is,
March 1, 1971 Incidentally, as a result of cur prelinincry inquiries concerning the disposition of neutron coerces it ic s trongly recc.-ended thut a closer control over the disse.;ition of these sourecc be esthblished and maintained.
In recent months varicus cccurrcaccc hcee highlighted the reed for ensuring the integrity of neutron ocurces.
Three instcnces of potential failure of neutrcn sources have recently been brou;ht to Mound Laboratory's ettention.
Cao ecurce, returned to 11 cur.d by Schlu=berger Well Services, Inc., Ecd c uipe count on the str-fccc of the source of 30,000 count: cecordic3 to Schlunberger.
This source is presently at Mound Labcrctory cnd is stored in the logging tcol in which it was uced.
A cceend ccurce, roccived frc= IUIA, Lewis Research Center, hcd cn appcrant bulge.
Likeuise, a source previously received frcu George U shinr, ten l'niversity had a notice-able bulge, and a radiograph of thic cource shoucd an appcrent crcch in the liner beneath the bulge.
In cdditicn, there cre on hand tuo returned sources which beccuce of uce hictory were not recced.
In storage are approx 4" tely 70 rauccchic ccurce: held for distribution i
to cducational institutions und:r prc rc=s cponsored by the EC Divicien of !!uclear Educarica cad Training.
The progran Mound proposes for the ccureca in the field concists of five phases as follcus:
9 1.
Examine all sources currently in ctorage at Mound, a)
Non-destructively tect 70 sources according to the MDT plan show in Tect Schedule I, attached.
b)
Destructively cnclyce five sources on hand at Metr:d according to the dcctructive cnalycic plan chon in Test Schedule II, ettcched.
II.
Locate potential proble= courecs in the field by acking all licensees to perforu tectc en ccurces they hold and cub =it to us the following infornction ca cach coucce.
a)
Wipe chech.
b)
Di=ensional check.
c)
Histery of use to which occh cource was put.
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v Mr. D. D. Davis l'.crch 1, 1971 III.
Recall problem sources dicccvered in phase 11 chove.
a)
Destructively an21y:2 cc 2 cf the sources (c;prori=:tely
- 10) according to Tart Schedule II, ctrached, b)
Atte=pt to cor cLate prebica ccurces with tice of.
fabrication, canufccturing conditions, curic sica, etc.
IV.
Sct:ple the rc=aining scurces in the field (~ 102) guided by any correlative factors derived in III.b. cbove.
a)
Destructively analyze cece (ap?rox*
tely 2 from each of t'
the 1, 5, and 10 cric cines) cccording to Test Schedule II, attached.
b)
Ucn-destructively test c11 the ec=ples accordin3 to Test Schedule I, attached (cpprc::# _tcly 120 sourcos).
V.
Evaluate data and cake rocccrendations.
Manpower and costs to perfors the cbove 'phccca of work are presently being cecu=ulated and will be incluled in a schedulo 139 which will be prepared for this work for the FY-1973 bud cr submission.
Phace:
3 I and II could be c cc=plished this fiscal year if an early deciaica to proceed is endo and funding 10 providad.
If you have any questions concerning this infor=2ti3n, please let cc know.
Very truly yours, CR.*G MAL S'GNED BY Witu/JA T. Q V5 U. T. Ccve, Director DOY!vic!
Nuclecr Opercr. ions Vallee :!=s Enclosures 3 cc:
D. D. Davis (2) 9 d-
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Test Schedule I NDT Scheme The non-destructive test scheme consists of the following inspections:
1.
ough alpha wipe check.
2.
Visual inspection of the integrity of the outer container.
3.
Dimensional inspection and comparison of the dimensional inspection results with information on the sources at the time of fabrication.
4.
Leak check of the outer container censisting of the following:
(a) imposition of high pressure helium on each source for a short period of time followed
, by (b) vacuum leak check of the source.
' 5. ' Radiographic inspection to determine the integrity of the liner of each source.
i 6.
Recalibration of the sources with respect to neutron emission can be performed as an optional inspection step.
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0 1.i Tes t Schedule II_
. Destructive Test Scheme l
The destructive test scheme consists of the following inspections:
1.
Evaluation of the history. of each source.
l 2.
Visual examination of the outer container surface and weld area.
1 Dimensional inspection and comparison with data on the 3.
l source at the time of fabrication.
I 4.
Helium leak check.
i.
I 5.
Radiography to determine the integrity of the outer concainer weld.
6.
(Optional) Nuclear measurements including neutron and ga=ma spectra, neutron and gamma dose raum s, and total I
I neutron emission.
i 7.
Internal gas pressure measurement and residual gas analysis on outer container.
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8.
Removal of the. outer container by machining.
9.
Sectioning and metallography of outer container weld.
10.
Wipe check and visual inspe ction of inner container.
11.
Leak check of inner container.
12.
Microprobe analysis on inne; container.
I 13.
Internal gas pressure measure =ent and residual gas analysis on ino r container.
14.
Removal of the fuel from the inner container and metallographic analysis of the weld and the fuel liner interface.
j 15.
(Optional) Fuel analysis including actinides, impurities, cad stoichiometry.
16.
Interim and finsi reports on tha analyses.
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MONS ANTO RESE ARCH CORPORATION NUCLEAR PRODUCTS DAYTON LAB PU-2 39-BE NEUTRON SOURCE M ANUFACTURIN3 PROCEDURE NSD/6 Scope:
This procedure is intended as a guide to the general prepara-tion of plutonium-239-beryllium neutron sources.
1.0 CONTAINER FABRICATION Material for inner and outer source capsules is checked for compliance to materials specifications.
Dimensions of fabricated container parts are checked with the drawing.
If critical dimensions are out of tolerance, a new container will be fabricated.
2.0 CLEANING PROCEDURE All parts are degreased with acetone and rinsed with clean acetone prior to assembly.
30 PLUTONIUM ASSAY (oLovE box OPERATION) e Plutonium metal is crushed into coarse chips using a hydraulic press.
The required quantity is then weighed and recorded to the nearest. 01 g r am.
4.0 BERYLLIUM CUP PREPARATION A beryllium cup is fabricated to fit within the tantalum inner container such that the total weight of beryllium is at least 50% of that of the plutonium.
A recess is drilled of sufficient size to contain the required plutonium.
50 PRIMARY ENCAPSUL ATION (glove Eox OPERATIONS)
'deighed quantity of Pu metal is loaded into the beryllium cup which is then inserted into the tantalum container.
Tantalum plug is fitted into the tantalum container and clcsure made by TIG fusion weld.
Capsule is then leak tes t-ed by placing in a pressure ch amber and s ubj ected to a mini-mum of 100 psig helium for at least 15 minutes, quickly re-moved and immersed in water to observe pressure of any bubbles indicating leakage.
If a leak is detected, repair is effected by rewelding and the capsule is retested.
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Monsanto Research Co tp o ration Pace 2 Pu-239-Be "eutrcn Source Manuf acturing Procedure NSD/6 6.0 SOURCE ACTIVATION (GLOVE EOX OPERATION)
The sealed tantalum capsule is placed in a chamber which is purged of air by. evacuating to less than 500 microns Hg pressure and refilling with helium.
This purging is repeated once, then a vacuum maintained at less than 500 microns Hg press ure.
The tantalum capsule is heated by induction coil to 1300-1500 C to initiate the exothermic reaction:
Pu + 13 Be - PuBe i 3 This will cause the tempera-ture of the capsule to increase to 1800-2000 C.
Induction heating is stopped on visible indication of self-heating.
Reaction proceeds to ecmpletion and source is allowed to cool naturally to room temperature before being exposed to the atmosphere in order to minimice oxidation of the tantalum.
The reacted material is now a neutron emitter and must be handled as such.
70 LEAK TESTING PRIMARY CONTAINER (GLOVE BOX. OPERATION)
Source is again tested for leaks per item #5.0 above.
Tantalum capsule is decontaminated by manual and ultrasonic scrubbing to swipe test of less than 1000 alpha counts per minute, and re-moved from glove box.
8.0 SECONDARY ENCAPSULATION Tantalum capsule is inserted in the outer stainless container body.
The stainless plug is inserte*d and closure made by TIG welding.
Closure is then leak tested by helium pressure bubble test des cribed in the above paragraphs.
9.0 LEAK TESTING SECONDARY CONTAINER The source is completely. cleaned to a swipe test of less than 10 alpha counts per minute and submitted to an additional test-ing or quality control. procedures that may be required.
If no helium leak test is perforned, the source is held seven days and the swipe test.is repeated to assure there is no leakage.
Initial and final swipe test counts are recorded and the source is neutron counted and assayed by calorimetry before preparing for shipment.
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c MONSANTO RESEARCH CORPORATION NUCLEAR SOURCES DEPARTMENT HELIUM LEAK TESTING PROCEDURES, NSD/l 1.1 PURPOSE Ta determine if leaks are present in sealed source cap-sules and/or assemblies.
1.2 GENERAL TEST METHOD Each source capsule shall be subjected to a pressure of 300 psi minimum with helium for a period of 1/2 hour in a suitable pressure chamber.
The capsule shall then be removed to an evacuation chamber.
The chamber shall be evacuated to a specified pressure and monitored with a mass-spectrometer type leak detector.
1.3 DZTAILED PROCEDURE 131 Pressurizing a.
Place the component in a pressure tube.
b.
Using helium bottle pressure, purge the pressure tube of air.
c.
Pressurise the tube to 300 psi minimum with helium and maintain for a period of 1/2 hour.
d.
Depressurize the pressure tube and remove,the com-ponent to the evacuation chamber.
1 3.2 Helium Leak Testing 1 3.2.1 General Creration of the leak detector shall be strictly in a.
accordance with the manufacturer's instructions.
At no time shall the leak detector pumps be used to evacuate external manifolds or vacuum chambers.
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Monsanto Research Corporation Page 2 Helium Leak Testing Procedures g3pf1 b.
The leak detector and vacuum system shall be cali-brated by using a calibrated leak before and after leak testing of each source capsule.
When checking th leak detector, the regulated power supply shall be turned on for at least ten minutes before any readings are taken and the internal pressure of the leak tester shall not exceed 0.1 micron for at least five minutes with the throttle valve wide open.
The leak detec a leak rate of1X10gorshallbeadjustedsothat standard cc/sec shall give a leak rate-meter reading of at least 90% of full scale.
Cali-bration is made using a standard helium leak of 5-9 x 10-8 standard cc/sec.
In calibrating the vacuum system, the roughing pumps shall be isolated from the system, and the standard leak placed at the furthest point from the leak de-tector.
After calibration, valve off the leak.
The system background readings shall be 10% or less of the leak calibration level in five minutes.
The pieces tested shall be free of dirt, grease, c.
burrs, etc., which would either tend to clog defects or damage the pressure and vacuum fittings.
d.
Leak testing shall be performed in well ventilated areas to minimize the possibility of detecting helium contaminated air.
e.
The vacuum system, exclusive of the vacuum chamber, shall be kept under a continuous dynamic vacuum.
1.3.2.2 Leak Testing Before each capsule is tested, the following blank a.
tests shall be performed (as shown in "b"
"d" below):
(1)
System background shall be determined by a test duplicating normal procedure, but having no source capsule in the vacuum chamber.
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Monsanto Research Corporation Page 3 Helium Leak Testing Procedures USD/l (2)
Source capsule background shall be determined by testing a solid bar of the same material and with approximately the same configuration as the source capsule.
The bar is to be sub-jected to the pressurization described in section 5.1 prior to being leak tested.
b.
Place the component to be tested inside the vacuum chamber.
c.
Evacuate the chamber and begin monitoring when the system pressure falls within the range of the leak detector.
This shall be done with a maximum leak detector internal pressure of 0.1 microns and with the instrument set for maximum sensitivity.
The required procedure is to crack open the throttling valve on the leak tester when the system vacuum reaches 5 microns or less.
A full open throttle is made only if the leak tester vacuum can be main-tained below 0.1 microns.
d.
If no helium signals are given after continuously pumping and testing with an open throttle valve for one minute, isolate the chamber from the vacuum pumps and accumulate any helium leakage for 30 minutes.
Monitor chamber following the procedure described in "c".
1.4 DATA REOUIRED Record the magnitude of leak indication and internal pressure of the system at the time of measurement for each of the following:
a.
Chamber background, b.
Standard leak.
c.
Solid bar background, d.
Each of the source capsules - including proper identification of the particular source capsule.
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Monsanto Research Corporation Page 4 Helium Leak Testing Prccedures NSD/1 1.5 ACCEPTANCE CRITERIA Any encapsulated sou"ce with an indication of leak greater than 1 X 10-b std cc/see shall be considered leaking and subject to repair and retest.
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MONSANTO RESEARCH CORPORATION NUCLEAR PRODUCTS DEPARTMENT DAYTON LAB HELIUM LEAK TESTING PROCEDURE, NSD/1A Scope:
This procedure is to be used when primary source capsule or singly encapsulated source containing an isotope with a half-life greater than five years are to be subjected to a helium mass spectrometer leak test.
1.0 PRELIMINARY PROCEDURES The capsule is to be subjected to a helium bubble test just after making the closure weld.
This test shall consist of pressurizing the capsule in a helium atmosphere at a pressure of 100 psi for 15 minutes.
Remove the capsule from the helium atmosphere and immerse it in water.
Bubbles from the capsule would be the indication of a leak.
If no leaks are indicated, the capsule is to be decontaminated so that a smear over.the surface of the capsule would remove no more than 9x10-5 pci of radioactive material.
2.&
TEST PROCEDURES The capsule would then be subjected to the helium leak tost procedure as outlined in procedure NSD/1.
MONSANTO RESEARCH CORPORATION NUCLEAR PRODUCTS DAYTON LAB CLEANLINEFS REQUIREMENTS, NSD/3 1.1 GENERAL PROVISIONS Fabrication and assembly of equipment should be conducted so as to facilitate cleaning and inspection for cleanliness, a"a to minimize contamination during fabrication., Equipment shall not be manufactured with the expectation of cleandsg only after completion of fabrication or assembly.
Component parts of equipment shall be clean and maintained in a clean condition up to and including assembly; thereafter, the assem-bled equipment shall be maintained in a clean condition.
Equipment supplied under this procedure shall be suitably clean for installation directly into a piping system without further cleaning.
It is extremely important that.contami-nation be kept to a minimum to prevent adverse effects upon the system such as accelerating the corrosion and wear of equipment.
Equipment shall be cleaned and shipped so that the visible contamination criteria specified by the buyer will be met when reinspected at destination prior to installation.
The requirements of this paragraph are not intended to require cutting of component seal welds for internal examination during receipt inspection by the installing activity.
1.2 ACCEPTANCE CRITERIA FOR CLEANLINESS Unless otherwise specified, equipment shall be clean to the extent that no contamination is visible to a person with normal visual aculty, natural or corrected, under an adequate lighting level on the surface being inspected.
Cleanliness need not be determined by an interpretation of the discolora-tion or dirt cbtained by wiping a surface with a wet or dry cloth.
This technique should be used to determine the clean-liness of surfaces which cannot be visually inspected due to inaccessibility or geometry.
In such cases, the cleanliness sha.1 be evaluated on the basis of type and quantity or contamination as well as the extent of discoloration.
Equip-ment which does not meet these requirements shall be re-cleaned in accordance with this procedure.
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hionsanto Research Corporation Page 2 Cleanliness Requirements NSD/3 1.3 MEASURES To PREVENT EQUIPMENT CONTAMINATICN 1.3.1 Welding or Brasing When welding or bracing of parts is performed, precau-a.
tions shall be taken to control splatter and to remove welding and bracing smoke from the equipment.
132 Exposure to Shop Atmosphere Components with complex internals, which are not ac-a.
cessible to subsequent cleaning shall not be exposed to a general shop area atmosphere more than is absolutely necessary.
1 3.3 1 Heat Treatment Precautions shall be taken to prevent contamination of a.
surfaces prior to and during heat treatment.
1 3.4 Use or Lubricants A lubricant may be employed during machining operations.
a.
Lubricating oil shall be completely removed from the work immediately following machining operations.
135 Restrictions Mercury or mercury compound-containing instruments or a.
equipment (such as thermometers, manometers, vacuum pumps) shall not be used for any service in connection with fluid systems or ccmponents during fabrication, assembly, packaging, installation, examination, testing, or repair.
It is not the intent of this procedure to prevent the use of fluorescent lighting fixtures.
b.
Lead of materials containing lead or lead compounds as a basic chemical constituent shall not be used in direct contact with the final cleaned surface of nickel base alloys equipment cr components.
Aluminum shall not be used either as soft pads or hammers to reduce marring during assembly or handling of nickel base alloys equip-ment or ecmponents.
It is not the intent of this pro-cedure to prevent the use of aluminum pipe caps.
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Monsanto Research Corporation Page 3 Cleanliness Requirements NSD/3 1.3.6 Hand)ine Equiement a.
In general, cleaned surfaces may be handled with clean hands; however, in production handling of intricate items, such as mechanism parts, clean gloves shall be used.
1 3.7 Exclusion of Foreign Materials a.
During fabrication and assembly of equipment requiring a high degree of cleanliness, extreme care shall be taken to prevent foreign m3terial from being introduced into the equipment.
1.4 MECHANICAL CLEANING REQUIREMENTS Filing and deburring shall be performed with clean carbide or tool steel hand tools.
Wire brushing shall be -done with clean corrosion-resistant steel brushes. Handling equipment shall be made of corrosion-resistant or chromium plated steels.
Grinding and polishing shall be performed with such a resin or rubber bonded aluminum oxide or silicon carbide grinding wheel or cloth polishing wheel or disc that will assure a cleanly cut surface.
Completed equipment shall be cleaned as required to remove any particles from operations such as grinding, polishing and filing.
Mechanical cleaning shall not be used as a final cleaning step.
If mechanical cleaning is used,it shall be followed through by a thorough liquid cleaning.
1.4.1 Degreasing by Immersion or Wicing a.
Degreasing of parts having no inaccessible areas or crevices may be performed by immersion in solvent or by wiping with a clean,lintless wiping cloth saturated with the solvent (unused acetone).
1.4.2 Decreasing of Crevices and Inaccessible Areas a.
Parts or surfaces containing crevices or inaccessible areas shall be degreased only by immersion in unused acetone.
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Monsanto Research Corporation Page 4 Cleanliness Requirements NSD/3 15 UJ"RASONIC CLEANING Cleaning methods employing ultrasonic cleaning equipment may be used.
1.6 DRYING REQUIREMENTS Drying may be accomplished by still air.
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.I' MONSANTO RESEARCH CORPORATION NUCLEAR PRODUCTS DAYTON LAB PO BE NEUTRON SOURCE MANUPACTURING PROCEDURE NSD/5 Scope:
This procedure is intended as an outline guide to the general preparation of 'a polonium-beryllium neutror. ccucce.
1.0 PREP Ab ATIO N 1.1 Assemble, prepare and check capsule components and associated hardware.
a.
Press ceryllium powder pellets as required.
Record mea-sured dimensions and weight of finished pellets.
2.0 TRANSFER PO-210 TO INNE? CAPSULE 2.1 Polonium is received electroplated on platinum gauzes, sealed in glass ampoules.
The gauces are removed from the glass ampoules and loaded into a vaporization " gun."
2.2 Vaporization gun is installed in a vacuum chamber within i
an induction heating coil.
23 Inner source capsule is inserted in a previously prepared chill block which is then positioned and sealed to the above mentioned vacuum chamber.
2.4 Vacuum chamber is evacuated and the vaporization gun is in-ductively heated to vaporize the polonium which recondenses on the walls of the inner capsule.
30 SEALING THE INNER CAPSULE 3.1 Inner capsule containing the Po-120 is removed frcm the vacuum chamber, withdrawn from the chill block and the previously prepared beryllium target material is inserted.
3.2 Capsule end cap is installed in place and a rough assay of the Po-210 content is made by calorimetry.
33 The capsule is then mounted in the welding chill block and placed in the welding rotator.
End cao is welded in place using the previously established welding procedure.
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Monsanto Research Corporation Page 2 PoBe Neutron Source Manufacturing Procedure NSD/5 3.4 Af ter visual examination of the weld, a dye penetrant test is performed, if required by the purchaser, and if thermal conditions of the capsule do not obviate the validity of this test.
35 Sealed inner capsule is decontaminated and any other required tests and control procedures. are performed including final assay of Po-210 content by precision steady-state calorimetry.
4.0 ACTIVATION OF NEUTRON EMISSION 4.1 Sealed inner capsule is placed in an induction heater coil and heated to above the vaporization point of polonium.
Dur-ing heating the neutron emiecion is monitored on a rate meter, and heating is stopped when no further increase in neutron emission can be observed.
4.2 Caps ule is allowed to cool and then checked for contamination.
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5.0 FINAL ENC APSULATION 5.1 Outer capsule is mounted in its welding chill block, in the welding rotator and the finished inner capsule is inserted into position.
5.2 Outer end cap is inserted and welded in place using the pre-viously established welding procedure.
5.3 Finished source is cleaned and final swipe test for alcha contamination is performed.
Swipe test must show not more than 1 x 10-5 pC removable alpha contamination.
5.4 Af ter final inspection the source is prepared for shipment.
6.0 GENERAL 6.1 Neutron counting per NSD/4 may be performed either on the ccmpletely finished source or on the finished inner capsule,
- whichever is most practicable.
6.2 Steps 2.0 through 4.2 inclusive, except the rough assay of step 3 2 and the testing in step 3.5, are performed in sealed, controlled atmosphere glove coxes.
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MONSANTO RESEARCH CORPORATION NUCLEAR PRODUCTS DAYTON LAB SPECIFICATION FOR NEUTRON COUNTING, NSD/4 1.0 PURPOSE The purpose of neutron counting is to determine the neutron emission of a source.
1.1 GENERAL TEST METHOD For this test a BF3 tube is used inside a polyethylene moderator, generally called a long counter, with a scaler to count the pulses from the tube.
The source to be counted is placed on the counting bar at a specific distance from the tube and.the source is rotated during the counting period to average the neutron flux around the source.
The source is counted a specific enount of time, normally three times.
A standard source is counted at the s ame dis t an ce.
The count rate of the source is compared to the s tandard count rate in order to determine the actual neutron emission rate of the unknown source.
1.2 DETAILED PROCEDURE 1.2.1 Precaration a.
The counter voltage is adjusted to 1300 0.V.
b.
The counting bar is set at the proper distance from the counting tube.
c.
A neutron background is taken and calculated into neutrons per second.
d.
A standard neutron source is counted a specific distance from the tube, three separate times.
These counts are averaged.
The standard neutron source has a known emission rate, so frcm the data taken, a factor (geometry and efficiency) is calculated.
This f actor is used in calculating the neutron emission of the unknown s ource.
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4 Monsanto Research Corporation Page 2 Specification for Neutron Counting NSD/4 1.2.2 Counting of the Samoles The sample is counted at the same distance as the a.
standard.
The time may vary depending on the emission rate of the source.
The time of the count is adjusted so that a minimum of 10,000 counts are recorded on the scaler.
b.
The data is then averaged and calculated using the factor to determine the emission rate of the unknown source.
The data is recorded and calculations are made as in-c.
dicated on Neutron Emission Form.
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MOMSANTO RESEARCH CORPORATION NUCLEAR PRODUCTS DEPARTMENT MANUFACTURINGPROCEDUREFORff[f*NEUTRONSCURCES NSD/9 Purpose The purpose of the procedure is to outline the method of producing quality neutron sources in a consistent manner.
- 1. Container Preparation The materials for the inner and outer containers are checked to see that they meet applicable specifications.
Dimensions of fabricated container parts are checked against the appro-priate drawing dimensions.
If the purchase order requires a formal inspection report, the dimensions are recorded on MRC Inspection Report Data Sheet (copy attached).
Upon receiving container parts in the Nuclear Products Department, the dimen-sions are rechecked as well as fit, finish, and appearance, and the acceptability noted on the Manufacturing Check List.
Out of tolerance or otherwise faulty parts are rejected.
- 2. Cleaning Procedure All parts are degreased with acetone and rinsed with clean, C. P. grade acetone prior to assembly.
- 3. Preparation of (FuBBe) Matrix (glove box operation)
(AmBe )
f[f"f[~28 is supplied as the powdered oxide.
The The required quantity is weighed out to the nearest 0.001 gram.
The weighed oxide is placed in a ball mill with typically four times as much beryllium powder by weight, and milled at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
The efficiency of milling is checked by observing the neutron yield.
- 4. Loading and Sealing Inner Capsule (glove box operation)
The prepared mixture is packed into the inner capsule.
The ale is temporarily closed and checked by neutron counting c
f;.
proper neutron output.
If the output is correct, the capsule is sealed by T.I.G. fusion welding.
- 5. Testing and Cleaning of Inner Capsule (glove box operation)
The seal of the inner capsule is checked by placing the capsule in a pressure chamber and applying 100 Psi of helium pressure for at least 15 minutes.
The capsule is then quickly removed i }I
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and immersed in a transparent container of water.
Eubbles emitting from the capsule indicate the presence of a leak.
Leaking capsules are repaired and retested before proceeding.
The acceptable capsules i.e.
those showing no bubbles after two minutes observation; are cleaned to a standard alpha swipe test of less than 1 x 10 3 pCi surface contamination.
The clean capsule may then be removed from the glove box and transferred to a fume hood for secondary encapsulation.
- 6. Secondary Encaosulation The completed inner capsule is inserted into the secondary container.
The seal is accomplished by T.I.G. fusion welding.
The welded capsule is helium bubble tested as in 5. above, then cleaned to a standard alpha swipe test of less than 1 x 10 5 pC1 surface contamination,'and subjected to further testing as may be required.
If no further testing is required, a second alpha swipe test 7 days after the first, to the same acceptance stan-dard, must be performed prior to release for shipment.
- 7. guality Control Inscection Quality Control inspection is performed on the secondard capsule as may be required by the purchase order.
Helium Leak testing, if required, is as specified in MRC procedure, NSD/1; Liquid Penetrant Test as specified in MRC procedure, NSD/2; and/or the capsule may be radiographed according to Mil-Std 271.
The neutron flux is calibrated according to MRC procedure NSD/4.
- 8. Final Assembly The completed capsule may now be further assembled by adding handling devices, etc. as may be indicated on appropriate assembly drawing.
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7 3g
PRELIMINARY PROCEDURE FOR RETURNING NEUTRON SOURCES 1.
Prior to the return of the Pu-Be neutron source (s), you will need to make known your intentions to the AEC leasing office by contacting:
Mr. P. A. Craig Plutonium Leasing Officer U. S. Atomic Energy Commission Richland Operations Office P. O. Box 550 Richland, Washington 99352 2.
Apply fbr an amendment.to your license to authorize, under the provision of CFR-71, delivery of the source (s) to a carrier for transport in the packaging that will be used for that purpose by contacting:
Mr. D. A. Nussbaumer Chief, Source and Nuclear Materials Branch Division of Materials Licensing U. S. Atomic Energy Commission Wachington, D. C.
20545 3.
Use an approved shipping container.
I will send you one if you so desire.
Please give me a week or two notice of your expected shipping date.
The shipping container is an approved U. S. Department of Transportation Specification 6J container for one curie sources, or 6M for shipping larger sources.
Instructions for loading, labels required and lead wire seal (s) will be furnished when warranted.
4.
Ship source (s) prepaid to:
Monsanto Research Corporation Mound Laboratory Mianisburg, Ohio 45342 Attn:
E. A. DeVer (SS Representative)
For:
Arthur F. Sc. idt
, e 5.
Complete the enclosed form, AEC-741 and mail to:
Mr. E. A. DeVer S. S. Representative Monsanto Research Corporation Mound Laboratory Miamisburg, Ohio 45342 6
Please send me any information you might have concerning the source (s), including name of manufacturer, fabrication date, total amount of enclosed plutonium, source intensity, physical dimensions, encapsulation materials, closure technique, and use to which the source was put (in terms of general source condition).
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