JAFP-14-0123, Response to Request for Additional Information (RAI) for Low Pressure Safety Limit License Amendment

Response to Request for Additional Information (RAI) for Low Pressure Safety Limit License Amendment

ML14322B022
Person / Time
Site:	FitzPatrick
Issue date:	11/18/2014
From:	Coyle L Entergy Nuclear Northeast, Entergy Nuclear Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
JAFP-14-0123, TAC MF2897
Download: ML14322B022 (6)

Text

Entergy Nuclear Northeast Entergy Nuclear Operations, Inc.

James A. FitzPatrick NPP P.O. Box 110 Lycoming, NY 13093 Tel 315-342-3840 Lawrence M. Coyle Site Vice President - JAF JAFP-14-0123 November 18, 2014 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

Response to Request for Additional Information (RAI) for Low Pressure Safety Limit License Amendment (TAC No. MF2897)

James A. FitzPatrick Nuclear Power Plant Docket No. 50-333 License No. DPR-59

References:

1. Entergy letter, Application to Revise Technical Specifications for Technical Specification Low Pressure Safety Limit, JAFP-13-0115, dated October 8, 2013

2. NRC letter, James A. FitzPatrick Nuclear Power Plant - Request for Additional Information Regarding Proposed Changes to the Technical Specification Low Pressure Safety Limit (TAC No. MF2897), dated September 24, 2014 On October 8, 2013, James A. FitzPatrick Nuclear Power Plant (JAF) submitted a license amendment request to revise its Low Pressure Safety Limit [Reference 1]. On September 24, 2014, the NRC submitted a request for additional information [Reference 2]. The attachment to this letter contains JAFs response.

There are no regulatory commitments in this submittal. Should you have any questions please contact Mr. Chris M. Adner at 315-349-6766.

JAFP-14-0123 Page 2 of 2 I declare under penalty of perjury that the foregoing is true and correct. Executed on November 18, 2014.

Sincerely, rence M. Coyle Vice President - JAF LMC/CMA/mh

Attachment:

Response to Request for Additional Information cc: Regional Administrator, Region I Mr. Douglas Pickett, Senior Project Manager NRC Resident Inspector Ms. Bridget Frymire, New York State PSC President NYSERDA

JAFP-14-0123 Attachment Response to Request for Additional Information (3 Pages)

JAFP-14-0123 Attachment Response to Request for Additional Information

RAI-01

The LAR references GESTAR II Compliance report, NEDC-33270P, Rev 4 that is only applicable to the GNF2 fuel type. TS Section 4.2.1 (Fuel Assemblies) states that a limited number of lead test assemblies (L TA) that have not completed representative testing may be placed in nonlimiting core regions. Provide the fuel type(s) in the JAF core.

RAI-01 Response:

The JAF Cycle 22 core consists of 560 GNF2 fuel assemblies.

RAI-02

Discuss how the potential of operating the JAF with a core with mixed fuel design might impact the LAR. Address in particular the scenario where the critical power ratio (CPR) correlations for the different fuel types have different lower bound pressure ranges.

RAI-02 Response:

The License Amendment Request is not affected by potential changes to core design in the future. The Cycle 22 core consists solely of GNF2 fuel assemblies for which GEXL17 is the appropriate correlation to evaluate Minimum Critical Power Ratio (MCPR). If different fuel designs are introduced into the core in the future an appropriate correlation will be applied to evaluate fuel performance with respect to MCPR. If that correlation was effective to a lower pressure and fuel for which the governing MCPR correlation was valid to 685 psig remained in the core, then no change to the low pressure safety limit would be required. If the MCPR correlation for the new fuel design was only valid to a pressure greater than 685 psig, then a license amendment would be required to support operation of that design since the higher pressure would be bounding. The low pressure safety limit must ensure validity of the MCPR correlation for all fuel in the core.

RAI-03

TS 2.1.1.2 specifies the safety limit (SL) on the minimum critical power ratio (MCPR). The proposed change in TS 2.1.1.2 expands the range of applicability of the SL on the MCPR to a lower pressure. The LAR will result in the SL on MCPR becoming applicable at a lower pressure. Discuss the impact of the proposed change in TS 2.1.1.2 on the determination of the MCPR core operating limits (Specification 3.2.2) in the core operating limit report as specified in TS Section 5.6.5.

RAI-03 Response:

The pressure regulator failure - open is not a limiting event for JAF and as such is not analyzed during core reload design. The events which are limiting are pressurization events such as feedwater controller failure - maximum demand and load reject without bypass or non-pressurization events such as rod withdrawal error and loss of feedwater heating. None of these events result in a significant pressure reduction, therefore expanding the range of applicability of the SL to a lower pressure has no effect on the MCPR core operating limit. In accordance with Technical Specification 3.2.2, the limiting condition for operation for MCPR is applicable for core thermal power 25%. This requires the reactor mode switch to be in the Run position to prevent reactor trip on a signal of Average Power Range Monitor Neutron Flux - High (TS Table 3.3.1.1-1.2.b). It also requires reactor pressure to be 825 psig to prevent Main Steam Isolation Valve closure on a signal of Main Steam Line Pressure - Low (TS Table 3.3.6.1-1.1.b). When the plant is operated in steady state in the expanded range of applicability of the safety limit, Page 1 of 3

JAFP-14-0123 Attachment Response to Request for Additional Information calculation of the MCPR is not required, again resulting in no impact on determination of MCPR core operating limits.

RAI-04

The proposed change in TS 2.1.1.2 expands the range of applicability of the SL on the MCPR to a lower pressure. Discuss if there is any reduction in the margin of safety because of the expanded range of applicability of the SL on the MCPR. Also provide the MCPRs for the JAF when the reactor is at a rated thermal power (RTP) of 25 percent and 10 percent core flow with steam dome pressures of 785 psig and 685 psig, respectively.

RAI-04 Response:

As previously stated in JAFP-13-0115 there is no reduction in margin of safety as a result of expanding the range of applicability of the GEXL correlation which allows decreasing the low reactor pressure safety limit. The ultimate capability protected by the low pressure safety limit is transition boiling at the reactor fuel cladding. The conditions under which this occurs are determined by the physical configuration of the fuel and the reactor thermal-hydraulics, neither of which are altered by the proposed change in safety limit. The margins which are enhanced by the proposed change are the design margin since the analyzed regime of applicability of the GEXL correlation has been widened through increased testing demonstrating adequate performance of the correlation over an expanded range; and operating margin since the proposed change will ensure that the plant will not enter an unanalyzed regime during a pressure regulator failed open event such as is potentially possible with the current low pressure safety limit.

MCPR values of 1.553 and 1.548 were calculated for 25% core thermal power and 10% core flow with reactor pressure at 800 psia and 700 psia respectively. These MCPR values were obtained using the control rod pattern corresponding to 25% core thermal power and 34% core flow during the October 2014 reactor startup and therefore do not represent steady state operation. The reactor state point of 25% power / 34% core flow is representative of operation with Reactor Water Recirculation pump flow near minimum flow. While plant procedures (AOP-8, Unexpected Change in Core Flow) prohibit operation in Mode 1 without forced circulation, UFSAR Figure 3.7-1 provides a value of approximately 30% of rated for core flow under natural circulation conditions at 25% power.

RAI-05

The proposed change in TS 2.1.1.1 modified the pressure from 785 psig to 685 psig. Why do the bases for TS 2.1.1.1 still refer to 785 psig on page 8 2.1.1-2 of the LAR?

RAI-05 Response:

The statement, Thus, a THERMAL POWER limit of 25% RTP for reactor pressure < 785 psig is conservative was retained on page B 2.1.1-2 of the Technical Specification Bases to be consistent with the previous statement that Full scale ATLAS test data taken at pressures from 14.7 psia to 800 psia indicate that the fuel assembly critical power at this flow is approximately 3.35 MWt. Since 685 psig is within the range 14.7 psia to 800 psia, the statement is true and no revision is technically required.

The Bases statement will be revised to Thus, a THERMAL POWER limit of 25% RTP for reactor pressure < 785 psig (including the GEXL17 correlation lower limit of 685 psig) is conservative to prevent future misunderstanding.

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JAFP-14-0123 Attachment Response to Request for Additional Information

RAI-06

The SL in TS 2.1.1.1 is intended to provide fuel cladding integrity protection during startup conditions. For operation at low pressures or low flows the thermal power limit of 25 percent RTP is based on full scale ATLAS test data. What would be the corresponding thermal power limit at 10 percent rated core flow and a reactor steam dome pressure of 685 psig if the GEXL 17 was used in formulating the basis?

RAI-06 Response:

Use of GEXL17 does not change the thermal power limit corresponding to 10 percent rated core flow. The 25 percent rated power limit is a conservative value which provides significant margin between fuel assembly operating power and critical power. This margin is not based on satisfaction of a prescribed value. The basic GEXL correlation is supported by ATLAS and Stern test data with GEXL17 coefficients determined from Stern testing of the GNF2 fuel design.

RAI-07

GE Safety Communication SC05-03 presented a typical pressure regulator failure open response for a low pressure isolation setpoint- analytical limit (LPIS-AL) of 720 psig. What is the LPIS-AL for the JAF? Discuss the applicability of the generic transient analysis in SC05-03 to the JAF. Discuss expected differences, if any, in the JAF plant response as compared to the generic transient analysis in SC05-03.

RAI-07 Response:

The Main Steam Isolation Valve low pressure isolation setpoint - analytical limit (LPIS-AL) for JAF is 825 psig.

JAF has not performed detailed transient analyses of the pressure regulator failure open event, however based on evaluations performed to support BWROG-TP-12-001 R0 (General Electric Hitachi Nuclear Energy NEDC-33743P, Rev. 0), BWR Owners Group Reload Analysis and Core Management Committee SC05-03 Analysis Report it is expected that JAF would respond to this event similar to other BWRs.

On failure of the pressure regulator in the open direction, turbine control and bypass valves will open to the position controlled by the Maximum Combined Flow Limiter (MCFL). Reactor water level swell will be insufficient to cause a main turbine trip and reactor and turbine inlet pressure will continue to lower until the Main Steam Isolation Valves (MSIVs) receive a closure signal on low pressure at the turbine inlet while in the Run mode (Mode 1). A reactor trip will occur on MSIV position switch actuation; however continued reactor depressurization will occur during the interval that the valves are closing until pressure reduction is terminated by full MSIV closure. No reduction in fuel thermal margins occurs as a result of this event.

Using the method provided by BWROG-TP-12-001, it has been demonstrated that a conservative minimum pressure reached during a pressure regulator failure open event at JAF will remain above the revised low pressure safety limit of 685 psig with margin.

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