ML20205R903
| ML20205R903 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 04/20/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20205R899 | List: |
| References | |
| NUDOCS 9904230365 | |
| Download: ML20205R903 (5) | |
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UNITED STATES j,I' j
NUCLEAR REGULATORY COMMISSION g
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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION
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RELATED TO AMENDMENT NO.174TO FACILITY OPERATING LICENSE NO. DPR-72 SUBCOOLING MARGIN MONITORING USING SAFETY PARAMETER DISPLAY SYSTEM FLORIDA POWER CORPORATION CRYSTAL RIVER UNIT 3 DOCKET NO. 50-302
1.0 INTRODUCTION
in a letter to the U.S. Nuclear Regulatory Commission (NRC) dated October 30,1998, Florida Power Corporation (FPC), the licensee for Crystal River Unit 3 (CR-3), requested NRC's approval of amendments to its Operating License DPR-72, by incorporating modifications to the improved Technical Specifications (ITS) for CR-3. The proposed modificat;ons would j
delete a note regarding the number of required channels for the Degrees of Subcooling function, and would subdivide the Core Exit Temperature (backup) function into two new functions in ITS Table 3.3.17-1, Post-Accident Monitoring Instrumentation, in a letter dated April 7,1999, FPC requested the amendment be implemented before commencing Cycle 12 operation. This letter did not affect the original no significant hazards consideration determination.
At present, each of the two primary subcooling-margin monitoring channels utilizes a non-safety-related Bailey digital monitor, if one of these two primary channels becomes inoperable, according to the current Note (d) of ITS Table 3.3.17-1, either channel of the Safety Parameter Display System (SPDS) which is monitoring this variable could be used as a backup, so that the Limiting Condition for Operation (LCO) for this function could be met. The proposed modification will remove the Bailey digital monitors and will designate the SPDS channels which are currently used as a bsckup, as the primary channels for the subcooling-margin monitoring function.
In their submittal, the licensee stated that the proposed ITS changes are the result of design modifications originally described and committed to in previous TS change request dated July 29,1997, and are scheduled to be implemented during the forthcoming Refueling Outage 11. The licensee further stated that the proposed modifications will significantly improve the reliability and availability of information required by the control room operators following a design basis accident (DBA). The proposed improvements include enhanced trending capabilities for determining the effectiveness of emergency core cooling systems during the mitigation and recovery phases following DBAs.
9904230365 990420 PDR ADOCK 05000302 P
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2.0 PROPOSED CHANGE
S For the current subcooling monitoring function, the licensee's proposed design modification will remove the existing Bailey digital monitors and will separate the current SPDS instrumentation loops into two redundant channels each to be supplied from independent emergency power sources. Each SPDS channel will be designated as the primary channel for the subcooling-margin monitoring function. In the current ITS, SPDS channels serve as a backup to the digital channels for this function. The 16 environmentally qualified core exit temperature thermocouples which provide signals to main control room recorders and to the SPDS will be divided into 2 redundant channels with each containing 8 thermocouples, and with each channel powered from an independent emergency power source. Additional physical restraints will be installed on the components to prevent motion and minimize the probability of damage to instruments during a seismic event. The existing Core Exit Temperature (backup) function will be divided into two new functions. The following proposed ITS changes are a result of the proposed design changes described above.
ITS Table 3.3.17-1, Post-Accident Monitoring instrumentation 2.11 Function 18, Core Exit Temperature (backup) will be divided into two separate functions.
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Function 18a, Core Exit Temperature (Thermocouple), is added with "2 thermocouples per core quadrant" as the number of required operable channels.
Function 18b, Core Exit Temperature (Recorder), is added with "2" as the number of required operable channels.
Both functions will reference Condition E from Required Action D.1.
2.2 The number of required channels for Function 21, Degrees of Subcooling, is revised to j
delete reference to Note (d), and the note is removed from ITS Table 3.3.17-1. Current Note (d) indicates that the two channels of subcooling margin are backed up by either of two indications of subcooling margin based on similar inputs through the SPDS. The note further states that at Mast one SPDS channel must be available to provide this backup, and that with both GPDS channels INOPERABLE, Condition C is applicable.
(Condition C requires restoration of one channel to OPERABLE status within 7 days, or be in MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and be in MODE 4 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.)
2.3 Revise surveillance requirements (SRs), emergency operating procedures (EOPs),
Bases and associated ACTION statements to reflect the proposed changes described above in items 1 and 2.
3.0 EVALUATION For the degree of subcooling function, the current design configuration uses two non-safety related Bailey digital monitors as the two primary channels. In accordance with the ITS Table 3.3.17-1, if either one of the digital monitor channels becomes INOPERABLE, either indication
. channel of the SPDS could be used as a backup to satisfy the ITS LCO. Since the proposed change removes the existing digital monitors and makes the SPDS channels the primary instrument channels for the subcooling margin monitoring function, Note (d) is no longer applicabte and removal of this Note reflects the proposed design upgrades to the SPDS. Once the SPDS upgrades are implemented, the SPDS will serve as the primary indication for subcooling margin function. Following deletion of Note (d), the number of channels required for Degree.s of subcooling function will be "2" to reflect two channels of SPDS being available.
In their submittal, the licensee stated that the proposed change will make the nurnber of channels required for this function consistent with other post-accident monitoring (PAM) functions. Also, the other proposed design improvements to the SPDS channels including additional redundancy, and improvement in seismic event sustaining capability will enhance reliability and availability of this function. The staff finds this acceptable.
In their submittal, the licensee stated that upon loss of both SPDS channels, the value of subcooling margin will be provided by manually plotting the current reactor conditions on a graphical plot of pressure and temperature. Thus,1anual-plotting will serve as a backup to the SPDS. Operator instructions for this backup effort are contained in the appropriate revised EOPs. The values of pressure and temperature used for the manual plotting will be obtained from Regulatory Guide (RG) 1.97 Type A, Category 1 instrumentation that is seismically qualified. The licensee further noted that this backup process of manually plotting reactor conditions was discussed in a letter to the staff dated October 29,1997.
The core exit temperature (CET) function using 16 thermocouples provides indication of the reactor coolant temperature as it exits the active region of the core. Although these thermocouples are environmentally qualified, they are not currently segregated into redundant channels. In their submittal, the licensee stated that the NRC staff, in a letter dated December 22,1997, for Amendment No.162, approved several changes to the CR-3 ITS including revising the number of required channels for the CET (backup) function and upgrading the classification of the Degrees of Subcooling variable from RG 1.97 Type B, Category 2, to a Type A, Category 1 variable. The proposed change will add a separate CET function and will separate the 16 thermocouples and associated instrumentation loops into two redundant channels with each channel powered from an independent source. This modification will ensure that the CET thermocouples meet the redundancy criterion in RG 1.97 for Type A, Category 1 instrumentation. Revised Functional Unit 18a will require a minimum of two thermocouples in each quadrant (at least one from each channel) to be OPERABLE and will make the number of required channels for this function consistent with the other PAM functions listed on ITS Table 3.3.17-1. The licensee further stated that two thermocouples in each core quadrant per channel will provide the capability to determine the overall distribution of temperatures across the core. This is acceptable to the staff.
Function 18b replaces the three existing, non-redundant, recorders on the main control board with two redundant recorders, one per each channel. Each recorder will be fed from separate and redundant emergency power supplies and will display temperature readings of eight thermocoup;es (two from each core-quadrant). The licensee stated that the proposed change will ensure that the redundancy criterion in RG 1.97 for Category 1 instrumentation will be met by the recorders. Also, the proposed change will make the number of required ITS channels for this function consistent with that for other PAM functions. This is acceptable to the staff.
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The revision to SRs, Action statements, associated Bases and EOPs are consistent with the above described proposed changes to the ITS, and the changes in the power distribution circuits and, therefore, are acceptable to the staff.
4.0 STATE CONSULTATION
Based upon a letter dated March 8,1991, from Mary E. Clark of the State of Florida, Department of Health and Rehabilitative Services, to Deborah A. Miller, Licencing Assistant, U.S. NRC, the State of F!crida does not desire notification of issuance of license amendments.
5.0 ENVIRONMENTAL CONSIDERATION
S The amendment changes requirements with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff has j
determined that the amendments involve no significant increase in the amounts, and no
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significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that this amendment involves no significant hazards consideration and there has been no public comment on such finding (64 FR 2246). - Accordingly, the amendment meets the eligibility criteria for categorical exc;usion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
Based on its review, the staff concludes that the proposed modification will improve the reliability and availability of the information required by the plant operator to assess the adequacy of core cooling following a DBA, and that the proposed ITS changes reflect design modifications for the subcooling margin monitoring function using the SPDS and core exit temperature indication function using 16 thermocouples which are consistent with the guidelines of RG 1.97 for PAM instrumentation. The staff therefore, finds the ITS changes to be acceptable.
Principal Contributor: S. V. Athavale A ril 20, 1999 Date:
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Mr. John Paul Cowan CRYSTAL RIVER UNIT NO. 3 Florida Power Corporation cc:
Mr. R. Alexander Glenn Ms. Sherry L. Bemhoft, Director Corporate Counsel Nuclear Regulatory Affairs (SA2A)
Florida Power Corporation Florida Power Corporation MAC-ASA Crystal River Energy Complex P.O. Box 14042 15760 W. Power Line Street St. Petersburg, Florida 33733-4042 Crystal River, Florida 34428-6708 Mr. Charles G. Pardee, Director Senior Resident inspector Nuclear Plant Operations (NA2C)
Crystal River Unit 3 Florida Power Corporation U.S. Nuclear Regulatory Commission Crystal River Energy Complex 6745 N. Tallahassee Road 15760 W. Power Line Street Crystal River, Florida 34428 Crystal River, Florida 34428-6708 Mr. Gregory H. Halnon Mr. Michael A. Schoppman Director, Quality Programs (SA2C)
Framatome Technologies Inc.
Florida Power Corporation 1700 Rockville Pike, Suite 525 Crystal River Energy Complex Rockville, Maryland 20852 15760 W. Power Line Street Crystal River, Florida 34428-6708 Mr. William A. Passetti, Chief Department of Health U.S. Nuclear Regulatory Commission Bureau of Radiation Control 61 Forsyth Street, SW., Suite 23T85 2020 Capital Circiel, SE, Bin #C21 Atlanta, GA 30303-3415 Tallahassee, Florida 32399-1741 Attomey General Department of Legal Affairs The Capitol Tallahassee, Florida 32304 Mr. Joe Myers, Director -
Division of Emergency Preparedness Department of Community Affairs 2740 Centerview Drive Tallahassee, Florida 32399-2100 Chairman Board of County Commissioners Citrus County 110 North Apopka Avenue Inverness, Florida 34450-4245