HomeMy WebLinkAboutCOM 0212.436 1996-1998 MAY 19 '97 a5:27PM ISOMEDIX CORPORATE P.c^/6
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'~7 ~i~Y 19 P(`l 2 15 May 19, 1997
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Ms. Margarita Hopkins COUNTY CF HAWAII
County of Hawaii °
Department of Research and Development
25 Aupuni Street; Room 219
Hilo, Hawaii 96720
Dear Ms. Hopkins:
In reference to your letter to George Dietz dated May 16, 1997,
we are pleased to provide the following responses.
1. If a piece 'of cobalt 60 is dropped in the pool, will the
.water get. contaminated? If we take the piece out of the
pool, is the water no longer contaminated?
Cobalt 60 source material is both nickel plated and doubly
encapsulated in stainless steel tubes to prevent the
possibility of exposed cobalt 60 coming in contact with the
water. Also, since cobalt 60 is not soluble in water,
should a piece of exposed cobalt 60 get into the pool
outside of its normal encapsulation, it could be easily
captured using the existing water filtration system and the
water would not be contaminated.
Only source-encapsulation designs registered with the USNRC
are approved for use in an industrial irradiator. The
manufacturers of cobalt 6o sources must submit their
encapsulation design along with the appropriate test data
indicating compliance to the criteria listed in 10 CFR part
36.21(a)(5), attached, to ,the USNRC for approval.
2. If only 10.4 of the original energy of the cobalt 60 remains,
what does this mean? Ts that IeveZ safe? Why do we sti31
have to dispose of it properly? Can we not just throw it in
the ground?
The half life decay of cobalt 60 is approximately 5.3 years.
" Therefore, after a little more than 16 years from theme dQate
of manufacture, the curie content of the cobalt 6 e
is approximately 10~ of its original value. ZIl6m FND GAP
g{~, Presented
MAY 2 0 1997
CORPORATE OFFICES • 11 APOLLO DRIVE, WHIPPANY,' NEW JERSEY 07981 • (201)887-4700 AX~----°-
MAY 19 '97 a5~28PM ISOMEDIX CORPORRTE P.3i6 ,
At this point the cobalt 60 capsule still possesses between
600 and 1000 curies of useful activity and must still be
handled with the same level of caution as a new capsule. If
not needed at this site, the capsule will be transferred to
one of the other 10 existing Isomedix irradiator facilities.
3. How many people died resulting from accidents in irradiation
plants all throughout the world? .Are data available on
this? How about the U.S.?
There have been four documented fatality events at
irradiator facilities worldwide out of a total of 170 such
facilities containing approximately 19o million curies of
,cobalt 60.
a. Italy, May 1975
An operator, while adjusting a conveyor belt, was
transported into the irradiation unit while the source
was exposed. Fault placed on poor management.
b. Norway, September 1982
A Maintenance Technician arrived on morning shift after
unattended night operations. Conveyor belt had jammed
and source failed to descend into the storage pool.
The door interlock was unbarred allowing entrance to
the irradiation room. The radiation monitor was
removed for repair. Fault placed on poor interlock
design.
c. El Salvador, February 1989
No preventative maintenance program, no operator
training program, overridden safety interlock systems
and no regulatory oversight were determined to be the
primary causes which allowed three workers to enter an
irradiator while the source was stuck in the raised
position. One of the three workers died,.
d. Israel, June 1990
Similar to the Norway event. The operator bypassed the
door interlock radiation monitor and entered the
irradiator with a non functional hand held geiger
counter while the source was stuck in the raised
position.
ISOIVIEOIX INC.
CORPORATE OFFICES • 11 APOLLO DRIVE, WHIPPANY, NEV/ JERSEY 07981 • (401) 887-4700 • FAX (201) 887-1476
MAY 19 '97 a5~3aPM ISOMEDIX CORPORATE P.4i6 ,
It should be noted that the same irradiator design was
associated with the Norway, El Salvador and Israel events.
After ttie Norway event, the irradiator manufacturer issued
an information notice along .with a design modification to
prevent a reoccurrence of the cause of the source rack jam.
The notice was apparently ignored by both the other
facilities.
There are .no documented fatalities associated with
industrial irradiators in the United States.
An interlock system designed to meet today's requirements
does not allow far any type of entry with the source in the
exposed position.
4. How long w.il1 it take for cobalt 60 to turn nonradioactive?
It depends on the. original level of activity but can be
approximated to be around 1~5 years.
5. Is there a guarantee from the manufacturer that the
cobalt 6o pencils will not Zeak?
Yes; The current guarantee is for 20 years, though pencils
properly stored will never leak.
6. What will happen if there is no water in the pool?
The radiation levels outside the concrete shield will be no
different than when the source rack is in the raised
position during routine production. With no water- in the
pool, the in-cell radiation monitor would be in an alarm
condition thus preventing entry. NRC regulations require
that the means to replenish water losses from the pool be
incorporated into the design.
7. Do you have any idea on cost of decontamination in case of
accident? How much insurance do you carry for this purpose?
For a small facility possessing less than 250,000 curies, as
planned for Hawaii, with a stainless steel pool liner, the
estimated cost would be in the order of $150,000. The
source manufacturer would be responsible for the cost of the
cleanup should the cause prove to be a manufacturing defect
in the source capsule.
ISOMEDIX INC.
CORPORATE OFFICES • 11 APOLLO DRIVE, WHIPPANY, NEVN JERSEY 07981 • (201) 887-4700 • FAX (201) 887-1476
MAY 19 '97 aS~SaPM ISOMEDIX CORPORATE P.Si6
In light of the extremely remote possibility of a
contamination event the Company has chosen to self insure
against such an occurrence.
Sincerely,
ni
~FJ~i
/ 6
Jonathan/ ~6ur,~Cj ~
~Directo /of Safe~y
cc: Mayor Steve Yamashiro
All Council Members
Ms. Diane Quibiquit
Mr. Rory Flynn
ISOMEOIX INC.
CORPORATE OFFICES • 11 APOLLO DRIVE, WNIPPANY, NEW JERSEY 07981 • (201) 887-4700 • FAX (201) 887-1476
MAY 19 '97 05:~1PM ISOMEDIX CORPORRTE P.6i6
PART 36 a LICENSES 1D RADIATION SAFETY REQUIREME). i FOR IRRADIATORS
(di Impact. A 2•kilogtam eta! weight, with paraonnel acpa door lacks to
2.5 wntimetara in dismatsr, must ha caveat room eccaa when radiation
dropped from a height of 1 mater onto levels era high. Aitemplad psnoansl
the feu source. entry while the monitor maesuns high
' (e) Vibration. She red eourp must be radiation Lvslr, must, ectivala the alarm
subjected 3 times for 10 minutes esch to described in paragraph (b) of this
vibrations evrrplmg from Z5 hero to asdion. She monitor rosy ba located in
St10 hertz with • peak empllluds of 5 the mtranee (normally nferrad to as the
times the mLration of gravity. la mess) but trot is the direct gdiatlon
additlon;each tat source mart be beam.
vibnrad for 30 minute u earh:aamsnt (d) Hafon the soutps move from their
E~yueacy found. ah(elthtd podtltm is • pmmeadc .
(Q :Punceure. A Sll-gram wdght and lrradiuo~. the comp ~nttolmud
ppin. t).3~oalimelar pia dLmeter, mace autometltally aetiwte paspitarous
be dropped from a height of I mater vidbL end audible eLems to alert
onto:the tad souroe. people in tM tedistlon room.thst the
(g) Bend.lf the length o[ the saurw is aromas will b• moved from their
mon.thsa 15 time Lrgu than the shielded. on: the ahnma`mmt give
mfaimum aoas•sectlond dlmrdoa. indivldu~wough Hms to lave the '
the lost source mud be sub)xted to a room before the crops leave the
toreof200nnswlansdlVosaty ahialdad'p~itlon.
equidistant from.ewo support gllndan, (e) Sec6 ndfaUoa Comm u ¦
the diatsnce bslwasn whirA is 29~ima panoramic irradiator tnut2 bare • cLsrly
the minimum noes-seriiooal dimewim vLlbla sad raadilyeonadbk control
of the satrrp. thu would allciur tm individual is the
Aeeus ~ Boom to mats the. rmpa estum'to Choir
Cal Far~i eatrsun to ¦ radiation room ti tttU ehldtlad pritloo.
rt a e irtediatae mmt have a ¢ (A ~ ~aU® r°°m of a
Paanra~ psoonmie ieadlator muse morale!
door or othv physiml harries to prevent m papm? slut ptevm4 tM emteor from
¢ inadvertent entry of pertrpnsl tf the moving ft~ the ahitdded poeitlon ,
m' aourps an sot is the atiiehied podtlon. udea the txatrol hr bees eetlretsd
Product conveyor syd®a may emus a sad the dada or bsedm to tlw radiation
Subpart G-Csaipa .nd PsAornunu bamtan as long a ffiey ntiably and nom 6a hr~aa dosed within a preset
ilequlrarnente for trradletore confidently funttioa a s herder. It time after eWrettoa of the cmtnt. -
mustnet he poeeibL /o more the (d tech egtrmta to the radiation
! 3s3t hrrorrnarwe criteria hr raw. sources out of tFteir shielded pofitloa if room of ~ panoramic hradlalor sad each -
aO1fO~ the door. ar haeria is
open. t)paring the saran®to tiro area within the
(a) Aaquinmenty. Sealed sources door or hsszier while the somtxa are patsonnd across herder of sa
inualled aRea• )uly 1,11193:. azpoead must ease the aom®s to underwater irradiator mart lava a dgo
U) Mud have a metl8mte of return promptly to thefr ahialded baertag the radlatlon ej~mbol sad the
ca~strs~ion iaeued under to CPR 32.210: position. The panamnal rmtrance door words, "Caution (as damger) ndiaeGire
(2) Muat ha doubly enmpsulsted: or bseiar mart hew a lack thst is matedal,° fhnersmie.inadiums must
(3i Must ace radiwctive material that operated by the esme key used to move aLo havra atgn datlmg "High ndfstloa
is a aondisparfibla r pnctital and that the aourca. She dean and baedme mud anr," but the dga may be umovsd.
is as inwluble a practical Ifthe saueoe sot pravent any Individual b the covered. m atharwir made iaopntive
is used in a wetsourr$dorega or wet• radLtlon room from laving. whoa the source ono fully ahie[dad.
sourctchmge irradiator, (h) In edditlaa, each eotranp to a (h) II the radiation room of a
(a) Mud be ennpsuLted in a material radiation nom at a panoramic irradiator psaonmic imdiemr br roof plugs to
reaistaat to general cotradop sad to mart have an independent bacTcup other movable obis it road sot be
¢ lomlired corrosem, ouch u 936E mac metro! to drtaet.panooas ®try poasibis to opera4 the for unless
~ stainlea rtrl or otlwr muedrl with while the comps ate aP•s•tL the ehLhliog lie la lee proper lagalon.
~ equivalent rasisteop if the sources ere 1]etactim of emery while !hs sources are 1Lis rsq~tiremant may he met by
far use in iaedutor pool; end a:posed rotor cause the nmwa to intarlo6ks that pnvamt opantlan tf '
(5) la,protatype testingg ottlre aeeled ratum to their fully ehieWed podtlon ehieldirtg carom pLad achy as .
wur®, mud' have been lasktaelsd and and mart aLo amivw • vWbls sad opsesting proodma
found: leak•frea eRar ach of the tests audible dsrm ro melee the individual mspectim of shieldlag fora operatlng.
deecihed is peragrapha (h) through (gl entering the nom swan of the Gerard.
of thin action. 't'he chum mud aLo shat u Lot op
(b) Temperotun. The ted'wutce niud other individual who L ondu of the
be hdd at -4o`C for 20 osinrrtes, 6lq°C entry: That 1adLviduel shell be trained
for i hour, and then be subjected to a on how to rrepond to the aLrm and
thermal shock feu with . t~pantms prepared to promptly randee m.ummon
drop fivm 90.0'C to 2n'C within 15 aeateunra.
roondt. (c).A ndiatlan momitar mart ba
(ci Precvura. The test source mud be provided to dates ehs pnaoo otbigh
ewio aub)act~d for u lent ti aainuta to radLtlm LvsL /a the ndletlon room of
m aatsimal prasun (aluolute] of 2 e panoramic fresdialor befon penomel
million newtons per aquera meter. entry, The monitor mud bs iategramd
F+bnrsty 211, 1993 38.1