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, 2007MEMORANDUM TO: Harold K. Chernoff, ChiefPlant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationFROM: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 electronicmail 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 licensee's submittal. The draft RAI is related to AmerGen's 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, 2007MEMORANDUM TO: Harold K. Chernoff, ChiefPlant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationFROM: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 electronicmail 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 licensee's submittal. The draft RAI is related to AmerGen's 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 statedDISTRIBUTION

Public BMarcus, NRRRidsNrrPMPBamfordAHowe, NRR GCranston, NRRLPL1-2 R/FRidsNrrPMEMillerSSun, NRRAccession No.: ML071630052 *via e-mail **via memorandumOFFICELPL1-2/PMLPL1-2/PMEICB/BCSRSB/BCNAMEPBamfordEMillerAHowe**GCranston*

DATE6/12/076/12/0705/21/200705/22/2007OFFICIAL RECORD COPY Enclosure DRAFTREQUEST FOR ADDITIONAL INFORMATIONHTP FUEL RCS PRESSURE-TEMPERATURE SAFETY LIMIT TECHNICAL SPECIFICATION AMENDMENT TAC NO. MD4910DOCKET NO. 50-289By letter dated March 22, 2007 (Agencywide Documents Access and Management SystemAccession 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 modelwas 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 DNBtransients 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 axialpower 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 tripfunctions, 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 pointsand mid point of proposed TS Figure 2.1-1.4.Identify the low reactor coolant pressure and high reactor outlet temperature interceptpoints of proposed TS Figure 2.3-1.5.Demonstrate that, for operation with measured values at the limits of the "AcceptableOperation" 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 outlettemperature.7.Identify the low reactor coolant pressure and high reactor outlet temperature interceptpoints for:(a)TS Variable Low Pressure Trip (VLPT) Limiting Safety System Setting (LSSS)Setpoint (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 10psig 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 inaccordance 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 thepredefined limits for the VLPT NSP As-Found Tolerance on a programmatic basis. The licensee should clarify this commitment. Aren't 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?