ML12310A382

Technical Specification Bases (Tsb) Changes

ML12310A382
Person / Time
Site:	Oconee
Issue date:	10/29/2012
From:	Gillespie T Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML12310A382 (8)

Text

Duke T.PRESTON Vice GILLESPIE, Jr.

President Pa"Energy Oconee Nuclear Station Duke Energy ONO1 VP / 7800 Rochester Hwy.

Seneca, SC 29672 864-873-4478 864-873-4208 fax T.Gillespie@duke-energy.com October 29, 2012 U. S. Nuclear Regulatory Commission Washington, DC 20555 Attention: Document Control Desk

Subject:

Duke Energy Carolinas, LLC Oconee Nuclear Station Docket Numbers 50-269, 50-270, and 50-287 Technical Specification Bases (TSB) Changes Pursuant to Technical Specification 5.5.15, Technical Specifications (TS) Bases Control Program, please find attached the latest changes to the Oconee Technical Specification Bases (TSB) 3.4.11. These changes are associated with and were implemented concurrent with Amendment Nos. 380, 382, 381. This change replaced the term "E-Bar, Average Disintegration of Energy" with "Dose Equivalent XE-133." This change is being made to implement a Limiting Condition for Operation (LCO) that is more attuned to the whole body radiological consequence analyses which are sensitive to the noble gas activity in the primary coolant but not to other, non-gaseous activity currently captured in the E-Bar definition.

If any additional information is needed, please contact Kent Alter at 864-873-3255.

Sincerely, T. Preston Gillespie, Jr.

Vice President Oconee Nuclear Station Aoo(

www. duke-energy.corn

I1 U. S. Nuclear Regulatory Commission October 29, 2012 Page 2 cc:

John Boska (By electronic mail only)

U.S. Nuclear Regulatory Commission One White Flint North, M/S O-8G9A 11555 Rockville Pike Rockville, MD 20852-2746 Victor McCree Regional Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE Suite 1200 Atlanta, Ga. 30303-1257 Senior Resident Inspector Oconee Nuclear Station Susan E. Jenkins, Manager Radioactive & Infectious Waste Management SC Dept. of Health and Environmental Control 2600 Bull St.

Columbia, SC 29201

Attachment #1 Revised TSB

RCS Specific Activity B 3.4.11 B 3.4 REACTOR COOLANT SYSTEM (RCS)

B 3.4.11 RCS Specific Activity BASES BACKGROUND The maximum dose that an individual at the exclusion area boundary can receive for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> following an accident, or at the low population zone outer boundary for the radiological release duration, is specified in 10 CFR 100.11 (Ref. 1) or 10 CFR 50.67 (Ref. 4). Doses to control room operators must be limited per GDC 19. The limits on specific activity ensure that the doses are appropriately limited during analyzed transients and accidents.

The RCS specific activity LCO limits the allowable concentration level of radionuclides in the reactor coolant. The LCO limits are established to minimize the dose consequences in the event of a steam line break (SLB) or steam generator tube rupture (SGTR) accident.

The LCO contains specific activity limits for both DOSE EQUIVALENT 1-131 and DOSE EQUIVALENT XE-133. The allowable levels are intended to ensure that doses meet the appropriate acceptance criteria.

APPLICABLE The LCO limits on the specific activity of the reactor coolant ensure that SAFETY ANALYSES the resulting 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> doses at the site boundary will not exceed the 10 CFR 100.11 (Ref. 1) or 10 CFR 50.67 (Ref. 4) dose guideline limits following an SGTR or a steam line break (SLB) accident. The SLB safety analysis (Ref. 2) assumptions bound the specific activity of the reactor coolant at the LCO limits and a total existing reactor coolant steam generator (SG) tube leakage rate of 300 gpd.

The analysis results are significantly impacted by the acceptance limits for RCS specific activity. Reference to this analysis is used to assess changes to the facility that could affect RCS specific activity as they relate to the acceptance limits.

The safety analysis shows the radiological consequences of an SLB and SGTR accident are within the dose guideline limits. Operation with iodine specific activity levels greater than the LCO limit is permissible, if the activity levels do not exceed the limits for more than 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.

RCS Specific Activity satisfies Criterion 2 of 10 CFR 50.36 (Ref. 3).

OCONEE UNITS 1, 2, & 3 B 3.4.11 -1 BASES REVISION DATED 10/12/12 I

RCS Specific Activity B 3.4.11 BASES (continued)

LCO The specific iodine activity is limited to 1.0 pCi/gm DOSE EQUIVALENT 1-131, and the noble gas specific activity in the primary coolant is limited to 280 jiCi/gm DOSE EQUIVALENT XE-1 33. The limits on specific activity ensure that the doses will meet the appropriate acceptance criteria.

The SGTR and SLB accident analyses (Ref. 2) shows that the 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> site boundary dose levels are within acceptable limits. Violation of the LCO may result in reactor coolant radioactivity levels that could, in the event of an SGTR or SLB, lead to site boundary doses that exceed the NRC dose guideline limits.

APPLICABILITY In MODES 1, 2, 3, and in MODE 4, operation within the LCO limits for DOSE EQUIVALENT 1-131 and DOSE EQUIVALENT XE-1 33 are necessary to limit the potential consequences of an SGTR or SLB to within the acceptable site boundary dose values.

In MODES 5 and 6, the steam generators are not being used for decay heat removal, the RCS and steam generators are depressurized, and primary to secondary leakage is minimal. Therefore, the monitoring of RCS specific activity is not required.

ACTIONS A.1 and A.2 With the DOSE EQUIVALENT 1-131 greater than the LCO limit, samples at intervals of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> must be taken to demonstrate that the specific activity is < 50 jiCi/gm. The Completion Time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is required to obtain and analyze a sample. Sampling must continue for trending.

The DOSE EQUIVALENT 1-131 must be restored to limits within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.

The Completion Time of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> is required, ifthe limit violation resulted from normal iodine spiking.

A Note to RA A.1 and A.2 excludes the MODE change restriction of LCO 3.0.4. This exception allows entry into the applicable MODE(S) while relying on the ACTIONS even though the ACTIONS may eventually require unit shutdown. This exception is acceptable due to the significant conservatism incorporated into the specific activity limit, the low probability of an event which is limiting due to exceeding this limit, and the ability to restore transient specific activity excursions while the unit remains at, or proceeds to power operation.

OCONEE UNITS 1, 2, & 3 B 3.4.11-2 BASES REVISION DATED 10/12/12 I

RCS Specific Activity B 3.4.11 BASES ACTIONS B..1 (continued)

With the DOSE EQUIVALENT XE-1 33 greater than the LCO limit, DOSE EQUIVALENT XE-1 33 must be restored to within limit within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. The allowed Completion Time of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> is acceptable since it is expected that, if there were a noble gas spike, the normal coolant noble gas concentration would be restored within this time period. Also, there is a low probability of a SLB or SGTR occurring during this time period.

A Note to RA B.1 excludes the MODE change restriction of LCO 3.0.4.

This exception allows entry into the applicable MODE(S) while relying on the ACTIONS even though the ACTIONS may eventually require unit shutdown. This exception is acceptable due to the significant conservatism incorporated into the specific activity limit, the low probability of an event which is limiting due to exceeding this limit, and the ability to restore transient specific activity excursions while the unit remains at, or proceeds to power operation.

C.1 and C.2 If the Required Action and associated Completion Time of Condition A or B is not met, or if the DOSE EQUIVALENT 1-131 is >50 pCi/gm, the reactor must be brought to MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />.

The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems.

OCONEE UNITS 1, 2, & 3 B 3.4.11-3 BASES REVISION DATED 10/12/12 I

RCS Specific Activity B 3.4.11 BASES SURVEILLANCE SR 3.4.11.1 REQUIREMENTS SR 3.4.11.1 requires performing a gamma isotopic analysis as a measure of the noble gas specific activity of the reactor coolant. This measurement is the sum of the degassed gamma activities and the gaseous gamma activities in the sample taken. This Surveillance provides an indication of any increase in the noble gas specific activity.

Trending the results of this Surveillance allows proper remedial action to be taken before reaching the LCO limit under normal operating conditions.

The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program.

If a specific noble gas nuclide listed in the definition of DOSE EQUIVALENT XE-1 33 is not detected, it should be assumed to be present at the minimum detectable activity.

A note modifies the SR to allow entry into and operation in MODE 4, MODE 3 with RCS average temperature < 500F prior to performing the SR. This allows the establishment of the necessary plant conditions to produce sufficient sample flow.

SR 3.4.11.2 This Surveillance is performed to ensure iodine specific activity remains within the LCO limit during normal operation and following fast power changes when iodine spiking is more apt to occur. The Surveillance Frequency is based on operating experience, equipment reliability, and plant risk and is controlled under the Surveillance Frequency Control Program. The Frequency, between 2 and 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> after a power change of

>_15% RTP within a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> period, is established because the iodine levels peak during this time following fuel failure; samples at other times would provide inaccurate results.

REFERENCES 1. 10 CFR 100.11.

2. UFSAR, Section 15.9,15.13, and 15.17.

3. 10 CFR 50.36.

4. 10 CFR 50.67.

OCONEE UNITS 1, 2, & 3 B 3.4.11-4 BASES REVISION DATED 10/12/12

Attachment #2 Markup of current TSB Note: A markup of the old TSB 3.4.11 was not provided for this effort. The changes for implementation of Amendments 380, 382, and 381, Deletion of E-Bar Definition and Revision to RCS Specific Activity, were significant enough to require an almost complete rewrite of the bases.