ML20216B403

Applications for Amend to Licenses NPF-10 & NPF-15,revising TS Section 1.1, Definitions, to Change Reference Used for Obtaining Dose Conversion Factors for Calculating Dose Equivalent I-131

ML20216B403
Person / Time
Site:	San Onofre
Issue date:	05/07/1998
From:	Nunn D SOUTHERN CALIFORNIA EDISON CO.
To:
Shared Package
ML20216B392	List: ML20216B386 ML20216B403 ML20216B414
References
NUDOCS 9805180063
Download: ML20216B403 (11)

Text

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1 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMISSION 1

Application of SOUTHERN CALIFORNIA ) j EDIS0N COMPANY, ET AL. for a Class 103 ) Docket No. 50-361 License to Acquire Possess, and Use

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a Utilization Facility as Part of ) Amendment Application Unit No. 2 of the San Onofre Nuclear ) No. 177 l Generating Station ) l SOUTHERN CALIFORNIA EDIS0N COMPANY, ET AL, pursuant to 10 CFR 50.90, hereby submit Amendment Application No. 177. This amendment application consists of Proposed Change Number NPF-10-492 (PCN 492), to Facility Operating License NPF-10. PCN 492 is a request to revise Unit 2 Technical Specification (TS) 1.1, " Definitions" to change the reference used for obtaining Dose Conversion Factors for calculating Dose Equivalent Iodine-131. I l

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- . Subscribed on this day of M , 1998.

v Respectfully submitted, SOUTHERN CALIFORNIA EDIS0N COMPANY  !

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s DwightE.Nuk n VicePresidenk State of California Count o'f Sin Di go /

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appeared blM khF rs.tJti,ts; , personaily known to me to de the person a

whose name is subscribed to the within instrument and acknowledged to me that he executed the same in his authorized capacity, and that by his signature on the instrument the person, or the entity upon behalf of which the person acted, executed the instrument.

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WITNESS my hand and official seal.

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1 UNITED STATES OF AMERICA i NUCLEAR REGULATORY COMISSION l

Application of SOUTHERN CALIFORNIA )

l EDISON COMFANY, ET AL. for a Class 103 ) Docket No. 50-362 l License to Acquire, Possess, and Use )

l a Utilization Facility as Part of ) Amendment Application Unit No. 3 of the San Onofre Nuclear ) No. 163 Generating Station i l l SOUTHERN CALIFORNIA EDIS0N COMPANY, ET AL. pursuant to 10 CFR 50.90, hereby 1

submit Amendment Application No. 163. This amendment application consists of Proposed Change Number NPF-15-492 (PCN 492) to Facility Operating j License NPF-15. 'CN 492 is a request to revise Unit 3 Technical Specification (TS) 1.1, " Definitions" to change the reference used for obtaining Dose Conversion Factors for calculating Dose Equivalent Iodine-131. i i

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Subscribed on this day of W , 1998.

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( -Respectfully submitted, SOUTHERN CALIFORNIA EDIS0N COMPANY

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By i Dw195tE.Nu 1 Vir.e President State of California County of San Diego [

On 6 < hY beforeme,fk [/hild 1/1 )[ D ersonally appeared 31J 1f/dE b. NR4U, personally known to me to be the person whose name is subscribed to the within instrument and at. knowledged to me that he executed the same in his authorized capacity, ani. that by his signature on the instrument the person, or the antity upon behalf of which the person acted, executed the instrument. ,

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1 ENCLOSURE 1 DESCRIPTION OFPROPOSEDCHANGENPF-10/15-492 I

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DESCRIPTION OF PROPOSED CHANGE NPF-10/15-492 Proposed Change Number (PCN) 492 is a request to revise Technical Specification 1.1, " Definitions," to change the reference for obtaining Dose Conversion Factors (DCFs) used to calculate Dose Equivalent Iodine-131 (I-131) for San Onofre Units 2 and 3.

EXISTING TECHNICAL SPECIFICATIONS Unit 2: See Attachment "A" Unit 3: See Attachment "B" PROPOSED TECHNICAL SPECIFICATIONS Unit 2: See Attachment "C" (redline and strikeout shown)

Unit 3: See Attachment "D" (redline and strikeout shown)

PROPOSED TECHNICAL SPECIFICATIONS )

I Unit 2: See Attachment "E" i Unit 3: See Attachment "F" DESCRIPTION OF CHANGES:

The proposed change to Technical Specification (TS) 1.1 would change the source for obtaining thyroid Dose Conversion Factors (DCFs) used in the definition of Dose Equivalent I-131. Currently, TS 1.1 requires use of Table E-7 of Regulatory Guide (RG) 1.109, Rev.1, NRC,1977 for obtaining DCFs. The proposed change would replace this with a reference to the Internationai Commission on Radiological Protection Publication 30 (ICRP-30), Supplement to Part 1, j pages 192-212, Tables titled, " Committed Dose Equivalent in Target Organs or Tissues per Intake of Unit Activity," as the source document for obtaining DCFs.

i BACKGROUND: l l

The calculation of dose consequences from radioactive releases at a nuclear power plant evaluates the radiation exposure to the thyroid. A key parameter needed to evaluate the radiological impact is the dose conversion factor. These factors enable the conversion of internally deposited radioactivity (in C1/ unit mass or volume) into dose equivalent to an organ (which is energy deposited in l tissues, usually in units of Rem). The Technical Specifications define DOSE l EQUIVALENT I-131 as that concentration of iodine-131 (microcuries/ cram) that alone would produce the same thyroid dose as the quantity and iso 1.opic mixture of iodine-131, iodine-132, iodine-133, iodine-134, and iodine-135 cctu 11y present. The TS definition of DOSE EQUIVALENT I-131 provides infonoation on the iodine DCFs which must be utilized when evaluating compliance with the TS 3.4.16 I l

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Reactor Coolant System Specific Activity limit for allowable c.oncentration level of radionuclides in the reactor coolant, and with the TS 3.7.19 Secondary S'pecifi'c Activity limit for allowable concentration level of radionuclides in the secondary coolant. These TS specific activity limits on DOSE EQUIVALENT I-131 ensure that thyroid doses to individuals at the exclusion area boundary, low population zone, and control room during a design basis accident will be within the dose limits promulgated in the Code of Federal Regulations, 10 CFR 100, Section 11 and 10 CFR 50, Appendix A, General Design Criterion 19.

Revision 1 of NUREG-1432, " Standard Technical Specifications, Combustion Engineering Plants," specifies thyroid dose conversion factors that can be used for calculating dose equivalent iodine-131 at Combustion Engineering Plants.

ICRP-30 is recognized in Revision 1 of NUREG-1432 as an acceptable source document for DCFs.

I DISCUSSION:

Numerous improvements in obtaining data on decay schemes and half-lives, some refinement to the effective energy terms, and the availability of more physical data for iodine and dose to the thyroid have resulted in refined DCFs. The proposed amendment to T3 1.1 would allow the utilization of more accurate DCFs when calculating the dose consequences associated with Reactor Coolant System (RCS) activity levels and postulated design basis events.

When San Onofre Nuclear Generating Stations (SONGS) Units 2 and 3 were licensed, the Combustion Engineering Standard TS (NUREG-0212) referenced only Technical Information Document (TID)-14844 (published in 1962) as a source for thyroid dose conversion factors. Consequently, the original SONGS TS definition of DOSE EQUIVALENT I-131 referenced TID-14844 for obtaining thyroid dose conversion factors.

In 1992, Revision 0 of NUREG-1432, " Standard Technical Specifications, Combustion Engineering Plants," was published. Revision 0 of NUREG-1432, specified two sources for thyroid dose conversion factors that could be used for calculating dose equivalent iodine-131 at Combustion Engineering Plants:

TID-14844 and Revision 1 of RG 1.109 (published in 1977). In 1996, Amendments 127 and 116 to the Technical Specifications for Units 2 and 3, respectively, revised TS 1.1 to change the reference for obtaining the thyroid DCFs used in the definition of DOSE EQUIVALENT I-131 from TID-14844 to Table E-7 of Revision 1 of RG 1.109.

Currently, there are three sources for DCFs widely used in the industry:

TID-14844, Revision 1 of RG 1.109, and ICRP-30 (published in 1980). Revision 1 of NUREG-1432 recognizes each of these documents as acceptable source documents for DCFs. As evidenced in Table 1 below, utilization of the ICRP-30 DCFs rather than RG 1.109 DCFs will effectively reduce calculated thyroid dose consequences h,

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of design basis accidents by approximately 28 percent, thereby providing additional design margin and fuel management flexibility when performing reload analyses. The cycle-specific reload analyses will ensure that the net effect of utilizing this resulting design margin is a dose consequence which is less than )

or equal to current licensing basis dose consequence. Gamma whole body and beta j skin radiological consequences are not addressed in this proposed amendment. ,

TABLE 1 - COMPARISON OF ICRP-30 AND REGULATORY GUIDE 1.109 THYROID INHA.LATION DOSE CONVERSION FACTORS IODINE THYROID INHALATION  % DCF ISOTOPE DOSE CONVERSION FACTORS Change with use of per ICRP-30 per RG l.109 ICRP-30 Sievert / Becquerel (a) Rem / Curie (b) Rem / Curie g)

I-131 2.9e-O 7 1.07e+06 1.49e+06 -28.0%

I-132 1.7e-09 6.29c+03 1.43 e+04 -56.0%

I-133 4.9e-08 1.81e+05 2.69e+05 -32.6%

i-134 2.9e-10 1.07e+03 3 73e+03 -71.2%

I-135 8.5e-09 3.15e+04 5.60e+04 -43.8%

(a) Sv/Bq data per ICRP-30, Supplement to Fart i. pages 205 to 211, Tables titled,

" Committed Dose Equivalent in Target Organs or Tissues per Intake of Unit Activity" (b) Rem /Ci data calculated with conversion factors of 100 Rem /Sv, and 3.7e10 Bq/Ci.

(c) Data per Regulatory Guide 1.109, Revision L Table E-7. )

RG 1.4, " Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Pressurized Water Reactors," references ICRP-2 i as an acceptable source for DCFs. ICRP-2 is the basis for RG 1.109,

" Calculation of Annual Doses to Man frcm Routine Releases of Reactor Effluents J for the Purpose of Cvaluating Compliance with 10 CFR Part 50, Appendix I," and was also used as the basis for the initial promulgation of 10 CFR 20.  ;

Subsequently,10 CFR 20 was rewritten to utilize ICRP-30, which established a l new set of DCFs. As stated in Federal Register, Volume 51, No. 6, dated Thursday, January 9, 1986, which proposed the change to 10 CFR 20:

"The intent of the revision is to improve NRC radiation protection standards by reflecting development in the principles that underlie radiation protection standards and advances in related sciences that have occurred since the promulgation of 10 CFR Part 20 nearly thirty years ago.

In particular the revision would put into practice many of the more recent recorrendations of the Internaticaal Commission on Radiological Protection

(ICRP) set forth in ICRP Publications 26, 30, 32. The expected result of

, p,romulgating and implementing the proposed revised re is an improved rule that provides better assurance of protection; establishes a clear health protection basis for limits and other regulatory actions taken to protect public heal th. . ."

i SONGS Units 2 and 3 are currently operating under the provisions of the revised 10 CFR 20, with the exception of the Radiological Effluent Controls Program.

The Radioactive Effluent Controls Program was not revised because the program was more restrictive than the provisions of the revised 10 CFR 20. This is in  !

accordance with the. implementation provisions provided in 10 CFR 20.1008(c).

Insummary,utilizationofthemorerecentICRP-30(1980) DCFs provides a more realistic assessment of predicted dose consequences associated with releases of radioactivity as compared to Revision 1 of RG 1.109 (1977).

l SIGNIFICANT HAZARDS CONSIDERATIONS: I The proposed change describea above shall be deemed to involve a significant hazards consideration if there is any positive finding in any one of the following areas.

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1. Will operation of the facility in accordance with this proposed change I involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The proposed change, which utilizes International Committee on '

Radiological Protection (ICRP)-30 methodology for determining dose equivalent Iodine-131, and therefore for evaluating thyroid dose consequences, does not involve any change to the method of operation of any plant equipment, nor does it modify any plant equipment. In addition, utilization of the ICRP-30 Dose Conversion Factors (DCFs) will effectively reduce calculated thytid dose consequences of design basis accidents, thereby decreasing the calculated thyroid dose consequences of previously  ;

evaluated accidents. '

Therefore, the proposed changes will not increase the probability or

. consequences of an accident previously evaluated.

2. Will operation of the facility in accordance with this proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No The proposed change does not modify the configuration of the units, involve any change to plant equipment or change the methcd of p' ant operation. The utilization of the ICRP methodology for determining DCFs uses more recent data which only affects calculations for determining thyroid dose consequences.

Therefore, this change does not create the possibility of a new or different kind of accident from any previously evaluated accident.

3. Will operation of the facility in accordance with this proposed change involve a significant reduction in a margin of safety?

Response: No The change to utilize the ICRP methodology for determining DCFs allows the use of more recent data which only affects calculations for determining thyroid dose consequences. ICRP-30 is recognized in Revision 1 of NUREG-1432, " Standard Technical Specifications, Combustion Engineering Plants," as an acceptable source document for DCFs. The new methodology will result in more accurate DCFs that will be used in the determination of dose consequences. Utilization of the ICRP-30 DCFs will effectively reduce calculated thyroid dose consequeaces of design basis accidents, thereby providing additional design margin.

Therefore, the proposed change does not involve a significant reduction in a margin of safety.

SAFETY AND SIGNIFICANT HAZARDS DETERMINATION:

Based on the above Significant Hazards Considerations, it is concluded that: (1) the proposed change does not constitute a significant hazards consideration as defined by 10 CFR 50.92; and (2) there is reasonable assurance that the health 7nd safety of the public will not be endangered by the proposed change.

l Moreover, because this action does not involve a significant hazards consideration, it will also not result in a condition which significantly alters the impact of the station on the environment as described in the NRC Final Environmental Statement.

PCN 492 Attachment A (ExistingPage)

SONGS Unit 2 l