ML071630052

Electronic Transmission, Draft Request for Additional Information Regarding the Reactor Coolant System Pressure - Temperature Safety Limit (TAC No. MD49100)

ML071630052
Person / Time
Site:	Three Mile Island
Issue date:	06/12/2007
From:	Peter Bamford NRC/NRR/ADRO/DORL/LPLI-2
To:	Chernoff H NRC/NRR/ADRO/DORL/LPLI-2
Bamford, Peter J., NRR/DORL 415-2833
References
TAC MD4910
Download: ML071630052 (5)

Text

June 12, 2007 MEMORANDUM TO: Harold K. Chernoff, Chief Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM: Peter Bamford, Project Manager /ra/

Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

THREE MILE ISLAND UNIT NO. 1 - ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING THE REACTOR COOLANT SYSTEM PRESSURE-TEMPERATURE SAFETY LIMIT (TAC NO. MD4910)

The attached draft request for additional information (RAI) was transmitted by electronic mail on June 7, 2007, to Mr. David Distel, at AmerGen Energy Company, LLC (AmerGen). This draft RAI was transmitted to facilitate the technical review being conducted by the Nuclear Regulatory Commission (NRC) staff and to support a conference call with AmerGen in order to clarify certain items in the licensees submittal. The draft RAI is related to AmerGens submittal dated March 22, 2007, regarding the proposed Three Mile Island, Unit 1 variable reactor coolant system low pressure trip setpoint change in the facility Technical Specifications (TSs) due to the introduction of AREVA High Thermal Performance (HTP) fuel. The draft questions were sent to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. Additionally, review of the draft RAI would allow AmerGen to determine and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not represent an NRC staff position.

Docket No. 50-289

Enclosure:

As stated

June 12, 2007 MEMORANDUM TO: Harold K. Chernoff, Chief Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM: Peter Bamford, Project Manager /ra/

Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

SUBJECT:

THREE MILE ISLAND UNIT NO. 1 - ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING THE REACTOR COOLANT SYSTEM PRESSURE-TEMPERATURE SAFETY LIMIT (TAC NO. MD4910)

The attached draft request for additional information (RAI) was transmitted by electronic mail on June 7, 2007, to Mr. David Distel, at AmerGen Energy Company, LLC (AmerGen). This draft RAI was transmitted to facilitate the technical review being conducted by the Nuclear Regulatory Commission (NRC) staff and to support a conference call with AmerGen in order to clarify certain items in the licensees submittal. The draft RAI is related to AmerGens submittal dated March 22, 2007, regarding the proposed Three Mile Island, Unit 1 variable reactor coolant system low pressure trip setpoint change in the facility Technical Specifications (TSs) due to the introduction of AREVA High Thermal Performance (HTP) fuel. The draft questions were sent to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. Additionally, review of the draft RAI would allow AmerGen to determine and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not represent an NRC staff position.

Docket No. 50-289

Enclosure:

As stated DISTRIBUTION:

Public BMarcus, NRR RidsNrrPMPBamford AHowe, NRR GCranston, NRR LPL1-2 R/F RidsNrrPMEMiller SSun, NRR Accession No.: ML071630052 *via e-mail **via memorandum OFFICE LPL1-2/PM LPL1-2/PM EICB/BC SRSB/BC NAME PBamford EMiller AHowe** GCranston*

DATE 6/12/07 6/12/07 05/21/2007 05/22/2007 OFFICIAL RECORD COPY

DRAFT REQUEST FOR ADDITIONAL INFORMATION HTP FUEL RCS PRESSURE-TEMPERATURE SAFETY LIMIT TECHNICAL SPECIFICATION AMENDMENT TAC NO. MD4910 DOCKET NO. 50-289 By letter dated March 22, 2007 (Agencywide Documents Access and Management System Accession No. ML070860968), AmerGen Energy Company, LLC (the licensee) submitted a license amendment request (LAR) regarding Three Mile Island Unit 1 Technical Specifications (TS). The proposed amendment would revise the reactor coolant system pressure-temperature limit to support use of the AREVA NP Mark-B-HTP fuel design. Based on the review of the information provided by the licensee, the staff has the following additional questions.

1. The licensee indicated that the transient core penalty for a specific transient core model was calculated based on the largest DNBR difference between the limiting Mark-B-HTP fuel rod in a full core model of the mark-B-HTP fuel and specific transient core model for all of the statepoints, condition I/II DNB transients, and axial power shapes.

Discuss the results of the transient core penalty analyses for condition I/II DNB transients with associated axial power shapes, and demonstrate that (1) the analysis scope in terms of the applicable condition I/II DNB transients and the allowable axial power shapes is adequate, and (2) the calculated value of the transient core penalty is a bounding value and acceptable for determining the thermal design limit that is used to calculate the reactor core safety limit.

2. Provide the basis for your determination that no setpoint changes to reactor trip functions, other than the variable low reactor coolant system pressure trip, are needed to assure that the analyses of record remain bounding, or new analyses meet the applicable acceptance criteria for DBEs.

3. Identify the reactor coolant pressure and reactor outlet temperature at the end points and mid point of proposed TS Figure 2.1-1.

4. Identify the low reactor coolant pressure and high reactor outlet temperature intercept points of proposed TS Figure 2.3-1.

5. Demonstrate that, for operation with measured values at the limits of the Acceptable Operation region of proposed TS Figure 2.3-1, there would be adequate assurance that the actual operating point will be conservative relative to the indicated Safety Limit line, given measurement errors consistent with the instrument channel uncertainties.

6. Identify the normal operating point for the reactor coolant pressure and reactor outlet temperature.

7. Identify the low reactor coolant pressure and high reactor outlet temperature intercept points for:

(a) TS Variable Low Pressure Trip (VLPT) Limiting Safety System Setting (LSSS)

Setpoint Enclosure

(b) Adjusted TS VLPT (c) VLPT Nominal Setpoint (NSP)

(d) VLPT As-Left Tolerance Band (e) VLPT Pre-Defined As-Found Tolerance Band.

8. Provide additional details concerning the methodology used to develop the VLPT 10 psig additional margin. Confirm that this additional margin has not been used in determining the VLPT Pre-Defined As-Found Tolerance Band.

9. Although the licensee has stated that the VLPT setpoint calculation is prepared in accordance with American National Standards Institute (ANSI) / Instrument Society of America (ISA) Standard 67.04.01-2000, Setpoints for Nuclear Safety-Related Instrumentation, and Recommended Practice ISA-RP67.04.02-2000, Methodologies for the Determination of Setpoints for Nuclear Safety-Related Instrumentation, the licensee has not directly addressed how the recommendations of Regulatory Guide (RG) 1.105, Revision 3, Setpoints for Safety-Related Instrumentation, are met. The licensee should address the regulatory positions of RG 1.105, Revision 3 or provide an acceptable alternative.

10. The Summary of AMERGEN Commitments includes a commitment to determine the predefined limits for the VLPT NSP As-Found Tolerance on a programmatic basis. The licensee should clarify this commitment. Arent the predefined limits for the VLPT NSP As-Found Tolerance Band determined and included in March 22, 2007 submittal? Why would the limits of the VLPT NSP As-Found Tolerance Band need to be recalculated on a programmatic basis? What are the periodicity or events that would trigger a recalculation of the VLPT NSP As-Found Tolerance Band? Would a recalculation of the VLPT NSP As-Found Tolerance Band be the cause for a revision to any of the VLPT related items in RAI 7 (a) - (d) above?