ML12339A486

Official Exhibit - NRC000054-00-BD01 - EPA - Cesium

ML12339A486
Person / Time
Site:	Indian Point
Issue date:	03/30/2012
From:	Environmental Protection Agency
To:	Atomic Safety and Licensing Board Panel
SECY RAS
References
RAS 22152, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01
Download: ML12339A486 (2)

Text

United States Nuclear Regulatory Commission Official Hearing Exhibit Entergy Nuclear Operations, Inc.

In the Matter of:

(Indian Point Nuclear Generating Units 2 and 3) c:..\,.~p..R REGlI~;. ASLBP #: 07-858-03-LR-BD01 NRC000054 Submitted: March 30, 2012

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Docket #: 05000247 l 05000286 Exhibit #: NRC000054-00-BD01 Identified: 10/15/2012

• 0 Admitted: 10/15/2012 Withdrawn:

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0.... Rejected: Stricken:

• • • • il Other:

Cesium The Basics Who discovered cesium and cesium - 137?

In 1860, Gustav Kirchh off and Robert Bunsen discovered nonradioactive cesi um in mineral wat er in German y. Radioactive cesium- 137, and many oth er radionuclide s that are used in nucle ar medicine, was discovered in the lat e 1930s by Glenn T. Sea borg and hi s coworke r, Margaret Melha se.

i'Top of pag e W h ere does cesium - 13 7 come from?

Nonradi oactive ces ium occurs naturally in various min erals. Radioactive ces ium - 137 is prod uced when uranium and plutonium abso rb neutrons and un dergo fissio n.

Examples of the uses of t his process are nucl ear reactors and nuclea r we apons. Th e splitting of uranium and plutonium in fi ssion creat es num erous fissio n products.

Ces ium - 137 is one of t he more w ell -kno wn fi ssion products .

i'Top of page What are the properties of cesium- 13 7?

Ces ium, as we ll as ce sium-13 7, is a soft, mall eable, sil very whit e metal. Cesium is one of only thre e metals that is a liquid near roo m temperature (83 OF). The half-life of ces ium - 137 is 30 years. It decays by emis sion of a beta particle and gamma rays t o barium - 137m.

i'Top of page What is cesium - 1 3 7 used for?

Ces ium - 137 is one of th e most co mm on radioisot opes used in indu st ry. Thousa nds of devices use ces ium - 137 :

• moisture-dens ity gauges, wid ely use d in th e const ructi on indu st ry

• leveling gauges, used in indu stries t o det ect liquid flow in pipes and t anks

• thickness gaug es , for meas uring thickness of sheet met al, pap er, film and many other pro ducts

• well -logging devices in th e drilling industry t o help characterize rock strata Cesium - 137 is also used in medical th erapy t o treat cance r.

i'Top of page Exposure to Cesium and Cesium - 137 How does cesium - 13 7 get into t he environment?

Ces ium - 137 in th e environm ent came from a vari ety of sou rces . The larg est sin gle so urce w as fall out from atm os ph eric nuclear w eap ons t est s in the 1950s and 1960s, which di spersed and depo sited ces ium - 137 wo rld-w ide. However much of th e cesium-1 37 from t estin g ha s now decayed.

Nucl ea r reactor w ast e and accide ntal releases such as the Chernobyl acci dent in th e Ukraine release so me ces ium - 137 t o the environment . Spent nuclear fu el reprocess ing plant wast es may introd uce small amounts t o the environm ent. However, t he U.S. does not currently reprocess spe nt nuclear fuel.

Alt hough hospitals and research laborat ori es generate wast es conta inin g cesium- 137, th ey usually do not enter t he environm ent. Occas ionally, industrial instruments containin g cesium - 137 are lost or st olen. Anyone who un wittingly handles t hem may be exposed . Th ese devices are typically metal , and may be co nsidered scrap metal and sold for recycli ng. If th ey find their w ay into a steel mill and are melted, they can ca use significant environmental co ntamination. Th ey may also be discarded and sent t o a municipal lan dfill , or sold for oth er reaso ns. Th ese devices should be consi dered dangerous.

i'Top of page How does cesium - 13 7 change in the environment?

Ces ium - 137 un dergoes radio active decay w ith th e emi ssion of bet a particl es and relatively strong gamm a radiation. Cesium- 137 decays t o barium- 137 m, a short-lived decay product, which in turn decays t o a nonradi oactive form of barium. Th e major dos e from cesi um-1 37 is fro m th e barium-1 37 . The half- life of ces ium - 137 is 30.17 years. Becau se of th e chemical nature of ces ium, it moves easily through th e environm ent. Thi s makes the cl eanup of cesium-1 37 difficult.

i'Top of page How do people come in contact with cesium - 13 7?

Everyo ne is expose d t o very small amounts of cesium- 137 in so il an d wat er as a result of atmosph eric fall out . In th e Northern Hemi sph ere, the averag e annual dose from ex posure to ces ium-137 associated with atmos pheric fall out is less than 1 mrem; th is dos e co ntinues t o diminish every year as cesium-1 37 decays.

Peo ple may al so be ex posed from co ntaminated sites :

Walki ng on cesium-1 37 contaminated so il could res ult in exte rna l expos ure t o gamma radiati on. Leaving the contamin at ed are a would prevent additional expo sure.

Coming in co ntact w ith waste material s at contaminate d site s could also result in external exposure to gamma radi ati on. Le avin g t he area wo uld al so end th e exposu re.

If ces ium- 137 contaminated so il becomes air-b orne as du st , breathing th e du st wo uld result in interna l expos ure. Becau se th e radiation emitting material is th en in th e body, leaving the sit e wo uld not end th e exposure.

Drin king ces ium - 137 contaminated w ater, would also place th e cesi um-13 7 in side the bod y, w here it wo uld ex pose living tis sue t o gamma and beta radiati on.

Peo ple may also unknow ingly handl e a strong in dustrial so urce of ces ium -1 37. For example, ce rtain moisture gauges co ntain ces ium - 137 sources .

i'Top of page

http://www.epa.gov/radiation/radionuclides/cesium.html