3F0998-11, Forwards LAR 238 to License DPR-72,correcting RCS Leakage Detection Capability of RB Atmosphere Gaseous Radioactivity Monitor Described in ITS Bases & FSAR

Forwards LAR 238 to License DPR-72,correcting RCS Leakage Detection Capability of RB Atmosphere Gaseous Radioactivity Monitor Described in ITS Bases & FSAR

ML20154C131
Person / Time
Site:	Crystal River
Issue date:	09/30/1998
From:	Terry J FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20154C135	List: 3F0998-11, Forwards LAR 238 to License DPR-72,correcting RCS Leakage Detection Capability of RB Atmosphere Gaseous Radioactivity Monitor Described in ITS Bases & FSAR ML20154C153 ML20154C158
References
3F0998-11, 3F998-11, NUDOCS 9810060159
Download: ML20154C131 (4)

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l September 30,1998 3F0998-11 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001

Subject:

License Amendment Request #238, Revision to Licensing Basis for Reactor Coolant System Leakage Detection Instrumentation

Reference:

FPC to NRC letter 3F1297-10, dated December 17, 1997, Crystal River Unit 3 Licensee Event Report 97-042, " Inadequate Engineering Evaluation Results in Loss of Diverse Reactor Coolant System Leak Detection Capability"

Dear Sir:

The purpose of this letter is to forward a proposed change to the Crystal River Unit 3 (CR-3) licensing basis. This proposed change will correct the reactor coolant system (RCS) leakage detection capability of the Reactor Building (RB) atmosphere gaseous radioactivity monitor described in the Improved Technical Specification (ITS) Bases and the Final Safety Analysis Report (FSAR). These documents currently identify that the gaseous radioactivity monitor is capable of detecting a one gallon per minute (gpm) RCS leak within one hour. The inability of the gaseous detector to meet the licensing basis was reported in the referenced Licensee Event i

Report. Florida Power Corporation has determined that this change to the licensing basis is an unreviewed safety question.

Several factors contribute to the difficulty in reliably detecting RCS leakage increases of one gpm within one hour using a gaseous radioactivity monitor. These include the relatively long half-life of Xe-133 (primary nuclide of detection), fluctuations in background levels of radioactivity, the existence of minor RCS leaks, improved performance of nuclear fuel, and improved primary water chemistry control.

Based on RCS radioactivity concentrations assumed in the Environmental Report, half-lives of the most abundant gaseous nuclides, and background radioactivity levels, a one gpm leak can conservatively be detected in approximately 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> by the CR-3 gaseous monitor.

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P PDR CRYSTAL RIVER ENERGY COMPLEX: 16760 W. Power Line Street

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U. S. Nuclear Regulatory Commission

- 3F0998-11 Page 2 of 3 Tlb rapid detection of small leaks by the gaseous monitor is not considered critical for several

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reasons.

First, the redundant RCS leakage detection instruments (RB ' sump level l

instrumentation and RB atmosphere particulate monitor) are capable' of detecting a one gpm leak within one hour. Second, both generic and CR-3 specific leak-before-break analyses of RCS piping indicate flaws will not propagate to critical crack sizes without first leaking at much greater than one gpm for extended periods of time. Third, other indications of RCS

-leakage are available such as makeup tank level, pressurizer level, and RB cooling unit condensate flow. Therefore, a high degree of assurance exists that leaks in the RCS primary loop piping will be detected, and actions initiated to safely shut down the reactor 'in a timely manner using any of the three separate leak detection methods required by the Technical Specifications or by other diverse methods.

The proposed change to the licensing basis is evaluated in Attachment A. The proposed changes to the ITS Bases and FSAR in strikeout / shadow format are provided in Attachment B. The proposed changes in revision bar format are provided in Attachment C.

If you have any questions regarding this letter, please contact Ms. Sherry Bernhoft, Manager, Nuclear Licensing at (352) 563-4566.

Sincerely,

. H. Terry -

Director, Nuclear Engineering and Projects JHT/sep i

1 Attachments xc:

Regional Administrator, Region II Senior Resident Inspector NRR Project Manager I

U. S. Nuclear Regulatory Commission 3F0998-11 Page 3 of 3 4

g STATE OF FLORIDA COUNTY OF CITRUS -

James H. Terry states that he is the Director, Nuclear Engineering and Projects for Florida Power Corporation; that he is authorized on the part of said company to sign and file with the Nuclear Regulatory Commission the information attached hereto; and that all such statements made and matters set forth therein are true and correct to the best of his knowledge, information, and belief.

b s H. Terry, Direc Nuclear Engineering and Projects Sworn to and subscribed before me this 30Mday of Seldembe

.1998, by James H. Terry.

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My Comm. Exp. 0ct. 25.1999 Comm. No. Cc 505458 Signature of Notary Public State of Florida

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FLORIDA POWER CORPORATION CRYSTAL RIVER UNIT 3 DOCKET NO. 50-302/ LICENSE NO. DPR-72 ATTACIMIENT A LICENSE AMENDMENT REQUEST #238, REVISION 0 Revision to Licensing Basis for Reactor Coolant System Leakage Detection Instrumentation License Amendment Request, No Significant Hazards Consideration Evaluation, and Environmental Impact Evaluation