ML070811166

Request for Additional Information Re. Amendment for Thermowell-Mounted Temperature Detectors

ML070811166
Person / Time
Site:	Cook
Issue date:	03/27/2007
From:	Tam P S NRC/NRR/ADRO/DORL/LPLIII-1
To:	Nazar M K Indiana Michigan Power Co
References
TAC MD3462, TAC MD3463
Download: ML070811166 (8)

Text

March 27, 2007Mr. Mano K. NazarSenior Vice President and Chief Nuclear Officer Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106

SUBJECT:

D. C. COOK NUCLEAR PLANT (DCCNP), UNITS 1 AND 2 - REQUEST FORADDITIONAL INFORMATION REGARDING PROPOSED AMENDMENT INVOLVING THERMOWELL-MOUNTED TEMPERATURE DETECTORS (TAC NOS. MD3462 AND MD3463)

Dear Mr. Nazar:

In a letter dated November 3, 2006, Indiana Michigan Power Company requested anamendment to the Technical Specifications of the units to reflect a plant modification that will replace the Reactor Coolant System resistance temperature detectors and associated bypass piping with fast response thermowell detectors mounted directly in the primary loop piping. The staff determined that additional information is need to complete its review. Accordingly, by e-mail dated January 16 and March 7, 2007 (publicly available at Accession Nos. ML070160275 and ML070660581, respectively), the staff provided draft questions to your personnel. On March 15, 2007, the staff discussed those questions with your personnel by telephone. Participants in the phone call agreed to modify or retain as-is the draft questions, resulting in the enclosed Request for Additional Information (RAI). Please respond by June 29, 2007. Feel free to contact me if you need clarification of this RAI.

Sincerely,/RA/Peter S. Tam, Senior Project ManagerPlant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor RegulationDocket Nos. 50-315 and 50-316

Enclosure:

Request for Additional Information cc w/encl: See next page

ML070811166 OFFICELPL3-1\PMLPL3-1/LAEICB/BCSRSB/BCLPL3-1/BC NAMEPTam PTam forTHarrisAHowe*GCranstonLRaghavanDATE3/27/073/27/073/6/073/27/073/27/07*Questions transmitted by memo of 3/6/07.

REQUEST FOR ADDITIONAL INFORMATIOND.C. COOK NUCLEAR PLANT, UNITS 1 AND 2 (DCCNP-1, -2)AMENDMENT REGARDING THERMOWELL-MOUNTED TEMPERATURE DETECTORS

Reference:

Application for amendment from Indiana Michigan Power company, November 3, 2006Reactor Systems Branch QuestionsA.1The TS changes associated with the resistance temperature detector bypass lineelimination have already been approved for DCCNP-1 (Amendment No. 296, dated October 6, 2006). As with DCCNP-1 (see licensee's letter dated May 31, 2006; Accession No. ML061600449), the response time for the OTT trip in DCCNP-2 will bemaintained at 8 seconds or less. The following events could lead to a reactor trip when the calculated OTT trip setpointis reached:1. Loss of electrical load/turbine trip 2. Uncontrolled rod cluster control assembly (RCCA) bank withdrawal at power

3. Chemical Volume Control System (CVCS) malfunction that results in a decreasein the boron concentration in the reactor coolant4. Inadvertent opening of a pressurizer safety or relief valveThe licensee has provided evaluations of the first three events for both Cook units(licensee's May 31 and November 3, 2006, letters). The fourth event, the inadvertent opening of a pressurizer safety or relief valve, is not in the licensing basis of either Cook unit. This event, like the uncontrolled RCCA bank withdrawal at power, could erode thermal margin (i.e., an OTT trip could occur as thermal margin is decreased by areduction in reactor coolant system (RCS) pressure as well as by an increase in power generation). Both the uncontrolled RCCA bank withdrawal at power event, and the inadvertent opening of a pressurizer safety or relief valve event are important in the determining the constants and coefficients in the OTT trip setpoint equation and of the OTT trip's dynamic time response characteristics. The OTT trip is designed to protect the plant against departure-from-nucleate-boiling(DNB) during uncontrolled RCCA bank withdrawal at power events that insert reactivity slowly. The high nuclear flux trip provides protection when reactivity is inserted more rapidly. The OTT trip, and the low pressurizer pressure trip, protect the plant againstDNB during the inadvertent opening of a pressurizer safety or relief valve events. The effectiveness of the OTT trip is verified by showing that the reactor trip signal isgenerated in time to prevent DNB, without taking credit for a reactor trip from the low pressurizer pressure trip logic. This has not been done for either of the Cook units, since these units do not include the inadvertent opening of a pressurizer safety or relief valve event in their licensing bases. Table 1 shows that the inadvertent opening of a pressurizer safety or relief valve eventwas specified in the Standard Format in October, 1972 (RG 1.70, Revision 1).Table 1: Standard Format and Content of Safety Analysis ReportsEvent analyses that are not in the Licensing Bases ofDCCNP-1 and -2RG 1.70R0 - 2/72RG 1.70R1 - 10/72RG 1.70R1 - 10/72Reactor coolant pump shaft breaklocked rotorlocked rotorT15-1 (3.4)

Single RCCA withdrawalT15-1 (3)T15-1 (3)T15-1 (4.3)

Inadvertent loading and operation of a fuel assembly inan improper positionT15-1 (18)T15-1 (15)T15-1 (4.7)Inadvertent actuation of the emergency core coolingsystem that increases RCS inventoryT15-1 (32)T15-1 (5.1)Inadvertent actuation of the CVCS that increases RCSinventoryT15-1 (4)T15-1 (4)T15-1 (5.2)Inadvertent opening of a pressurizer PORVT15-1 (13)T15-1 (6.1)Radiological consequences of failure of small linescarrying primary coolant outside containmentT15-1 (26)T15-1 (22)T15-1 (6.2)Table 2 shows that DCCNP-1 and DCCNP-2 were licensed 2 and 5 years, respectively,after RG 1.70 incorporated the inadvertent opening of a pressurizer safety or relief valve event. Table 2: Chronology June, 1966A Guide for the Organization and Contents of Safety Analysis ReportsJuly, 1967Proposed General Design Criteria February, 197110 CFR 50, App A, General Design Criteria July, 197110 CFR 50, App A, General Design Criteria February,1972RG 1.70, Rev 0, Standard Format and Content October, 1972RG 1.70, Rev 1, Standard Format and Content August, 1973ANSI N18.2-1973, Nuclear Safety Criteria for Design of PWRs October, 1974DCCNP-1 was licensed January, 1975DCCNP-1 achieved initial criticality September, 1975RG 1.70, Rev 2, Standard Format and Content November, 1975NUREG-75/087 SRP December, 1977DCCNP-2 was licensed March, 1978DCCNP-2 achieved initial criticality November, 1978RG 1.70, Rev 3, Standard Format and Content October, 1986DCCNP-2, Cycle 6 SAR August, 1989"Analysis of D.C. Cook Unit 2, Cycle 8 Reload" Table 2 also shows that DCCNP-1 and -2 were licensed more than a year after theissuance of ANSI N18.2-1973, "Nuclear Safety Criteria for Design of PWRs." This standard categorizes the analyzed events according to expected frequency of occurrence, and lists the inadvertent opening of a pressurizer safety or relief valve event as an example of a Condition II (an event of moderate frequency) event. One year after DCCNP-2 was licensed, another revision of RG 1.70 and the Standard Review Plan were issued. Both contained the inadvertent opening of a pressurizer safety or relief valve event. Nevertheless, the licensee continued to maintain that this event, along with six others listed in Table 1, were not in the licensing bases of DCCNP-1 and -2. The NRC staff accepted this position as recently as 1989 (letter from J. G. Giitter, August 3, 1989). At that time, the licensee and Westinghouse asserted that the seven events were analyzed or evaluated by ANF in response to NRC staff questions regarding the use of ANF methodology in the licensing of ANF-supplied fuel. They were not part of the licensing basis for Westinghouse-supplied fuel. As such, they were not to be considered as part of the licensing basis when the Cook fuel supply contracts reverted to Westinghouse.The seven events of Table 1 are not in the current licensing bases of DCCNP-1 and -2. Yet, when issuing an amendment, the NRC staff needs to be able to make the statement that there is "reasonable assurance that the activities authorized by [the]

amendment can be conducted without endangering the health and safety of the public" (i.e., the absence of an issue in the current licensing basis is not a cause prohibiting the staff from reviewing that issue where safety may be affected by the proposed amendment). The fact that the current DCCNP-1 and -2 licensing bases do not include the aforementioned seven event evaluations or analyses should not prevent the NRC staff to question whether there is a significant reduction in a margin of safety related to one of these events. The subject amendment application would result in a change to the OTT trip. Accordingly, the staff requests an analysis, or equivalent, to providereasonable assurance that the modified OTT trip will not significantly reduce a marginof safety (e.g., thermal margin) during an inadvertent opening of a pressurizer relief or safety valve, an event that could demand a reactor trip through the OTT trip logic.

A.2[Original draft question deleted per telephone discussion of March 15, 2007.]A.3Please verify that despite the proposed changes to the allowable values for the OPTand the OTT trip set points, the UFSAR analysis limits will be maintained.A.4The calculations performed by the NRC staff show that the changes in the allowablevalues are within a fraction of a degree Fahrenheit. Show that the new thermowell resistance temperature detectors (RTDs) have the capability to measure this difference in the allowable value. Instrumentation and Controls Branch QuestionsB.1Enclosure 2, Section 4.0, discusses in general, the instrument uncertaintyconsiderations for the calculations of the allowable value for OTT and OPT andEnclosure 3 provides the generic D. C. Cook Nuclear Plant setpoint methodology found acceptable by the NRC. Please provide the detailed calculations, including all actual values used for uncertainties, that show justification for the increase in allowable values for OTT and OPT. Also, please provide the source and/or justification for eachuncertainty value used in the calculation.B.2Enclosure 2, Section 3.0, states that the three hot-leg scoops in each reactor coolantsystem (RCS) loop will be modified to accept the new thermowells, which will contain the new, fast-response RTDs and that a hole will be drilled through the end of each scoop to facilitate flow past the RTD. How large is the drilled exit hole in comparison to the scoop's water-entry cross-section size? How was it determined that this exit hole size was sufficient to not cause reduced flow through the scoop that could potentially add to a delay in the response time of the measurement of RCS temperature changes or even introduce another uncertainty in the measurement?B.3[Original draft question deleted per telephone discussion of March 15, 2007.]

B.4Enclosure 2, Section 3.0, describes in general, the arrangement whereby the threeRTDs in an RCS loop will be electronically averaged to obtain a single hot-leg RCS temperature for that loop. Please describe the averaging function. Can a failure of one of the three RTDs in an RCS loop be automatically identified and taken out of the averaging equation by the new electronic averaging circuit?B.5[This question was not discussed in the March 15, 2007, phone call.] Enclosure 3 statesthat the NRC concluded that the DCCNP allowable value calculation methodology is acceptable in a letter dated June 1, 2005 (Reference 6). However, based on the staff concerns identified in the NRC Regulatory Issue Summary (RIS) 2006-17 (Reference 4),

please provide a statement confirming that the setpoints for OTT and OPT areLimiting Safety System Settings for the variables on which a Safety Limit (SL) has been

placed.B.6[This question was not discussed in the March 15, 2007, phone call.] The NRC letter tothe Nuclear Energy Institute, Setpoint Methods Task Force, dated September 7, 2005 (Reference 1), describes setpoint-related technical specifications (SRTS) that are acceptable to the NRC for instrument settings associated with SL-related setpoints.

Specifically, Part "A" of the Enclosure to the letter provides limiting condition of operation notes to be added to the TS, and Part "B" includes a check list of the information to be provided in the TS Bases related to the proposed TS changes.a.Describe whether and how you plan to implement the SRTS suggested in theSeptember 7, 2005, letter. If you do not plan to adopt the suggested SRTS, then explain how you will ensure compliance with 10 CFR 50.36 by addressing items b and c, below.b.As-Found Setpoint Evaluation: Describe how surveillance test results andassociated TS limits are used to establish operability of the safety system. Show that this evaluation is consistent with the assumptions and results of the setpoint calculation methodology. Discuss the plant corrective action processes(including plant procedures) for restoring channels to operable status when channels are determined to be "inoperable" or "operable but degraded." If the criteria for determining operability of the instrument being tested are located in a document other than the TS (e.g. plant test procedure), explain how the requirements of 10 CFR 50.36 are met.c.As-Left Setpoint Control: Describe the controls employed to ensure that theinstrument setpoint is, upon completion of surveillance testing, consistent with the assumptions of the associated analyses. If the controls are located in a document other than the TS (e.g. plant test procedure), explain how the requirements of 10 CFR 50.36 are met.References 1.Letter from P. L. Hiland, NRC, to NEI Setpoint Methods Task Force, "TechnicalSpecification for Addressing Issues Related to Setpoint Allowable Values," dated September 7, 2005 (Accession No. ML052500004). 2.Letter from B. A. Boger, NRC, to A. Marion, "Instrumentation, Systems, and AutomaticSociety (ISA) S67.04 Methods for Determining Trip Setpoints and Allowable Values for Safety-Related Instrumentation," dated August 23, 2005 (Accession No. ML051660447).3.Letter from J. A. Lyons, NRC, to A. Marion, NEI, "Instrumentation, Systems, andAutomation Society S67.04 Methods for Determining Trip Setpoints and Allowable Values for Safety-Related Instrumentation," dated March 31, 2005 (Accession No.

ML050870008).4.NRC Regulatory Issue Summary 2006-17, "NRC Staff Position on the Requirements of10 CFR 50.36, "Technical Specification," Regarding Limiting Safety System Setting During Periodic Testing and Calibration of Instrument Channels", dated August 24, 2006 (Accession No. ML051810077).5.Technical Specification Task Force (TSTF) recommendation for Standard TechnicalSpecification (STS) changes, TSTF-493, "Clarify Application of Setpoint Methodology for LSSS Functions", Revision 0, January 27, 2006 (Accession No. ML060270503).6.Letter from J. Donohew, NRC, to M. Nazar, I&M, dated June 1, 2005, ParagraphsG.1.2.a, G.1.2.b, and G.3.2 of the Safety Evaluation for the conversion of the CNP TS to Improved Technical Specifications (Accession No. ML050620034).

Donald C. Cook Nuclear Plant, Units 1 and 2 cc:Regional Administrator, Region IIIU.S. Nuclear Regulatory Commission Suite 210 2443 Warrenville Road Lisle, IL 60532-4351Attorney GeneralDepartment of Attorney General 525 West Ottawa Street Lansing, MI 48913Township SupervisorLake Township Hall P.O. Box 818 Bridgman, MI 49106U.S. Nuclear Regulatory CommissionResident Inspector's Office 7700 Red Arrow Highway Stevensville, MI 49127Kimberly Harshaw, EsquireIndiana Michigan Power Company One Cook Place Bridgman, MI 49106Mayor, City of BridgmanP.O. Box 366 Bridgman, MI 49106Special Assistant to the GovernorRoom 1 - State Capitol Lansing, MI 48909Susan D. SimpsonRegulatory Affairs Manager Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106Michigan Department of Environmental Quality Waste and Hazardous Materials Div.

Hazardous Waste & Radiological Protection Section Nuclear Facilities Unit Constitution Hall, Lower-Level North 525 West Allegan Street P. O. Box 30241 Lansing, MI 48909-7741Lawrence J. Weber, Plant ManagerIndiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106Mark A. Peifer, Site Vice President Indiana Michigan Power Company Nuclear Generation Group One Cook Place Bridgman, MI 49106