ML14230A913

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Enclosure - Fuel Performance and Cask Internals - July 17, 2014, Summary of Meeting with Exelon Corporation to Discuss Request for Additional Information No. 4 to the Calvert Cliffs ISFSI License Renewal Application (Docket No. 72-08) TAC L
ML14230A913
Person / Time
Site: Calvert Cliffs  Constellation icon.png
Issue date: 08/18/2014
From: Einziger R
NRC/NMSS/SFST
To:
Goshen J
Shared Package
ML14230A903 List:
References
TAC L24475
Download: ML14230A913 (15)
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Fuell Performance F P f and Cask Internals Robert E. Einziger, Ph.D.

Meeting to provide Calvert Cliffs Nuclear Power Plant, LLC,, the opportunity pp y to discuss request q for information responses regarding the Calvert Cliffs ISFSI License Renewal with the NRC Staff July 17, 2014 1

Introduction

  • Current guidance in NUREG-1927 NUREG 1927 does not address cask/canister internals that are considered important to safety

- Fuel performance for retrievability and cladding integrity functions

- ISG-24 Final Guidance (ML14058B166)

AMP Element 1:

Scope of the Program NUREG-1927: The scope of the program should include the specific structures and components subject to an aging management review

  • Components/Materials of Construction

- Specify spent fuel maximum burnup

- Specify S if cladding l ddi ttypes and d maximum i cladding l ddi temperature t t

  • Environment

- Dry y helium e u

  • Aging effects for material/environment combinations

- Fuel cladding breach

- A Assemblybl di distortion t ti

- Residual moisture after drying

- Changes in the hydride structure of the cladding 3

AMP Element 2:

Preventive Actions NUREG-1927: Preventive actions should mitigate or prevent the applicable aging effects

- Casks/Canisters dried per the accepted guidance in NUREG -1536, Standard Review Plan for Dry Cask Storage Systems

- Backfilled with helium cover gas

- Maximum cladding temperature is maintained below the recommended ISG-11 Rev 3 limits 4

AMP Element 3:

Parameters Monitored/ Inspected NUREG-1927: Parameters monitored or inspected should be linked to the effects of aging on the intended functions of the particular structure and component

  • Surveillance demonstration program meeting ISG-24:

- Maximum cladding temperature

- Inspection for the presence of fission gas in the cover gas

- Inspection for presence of water vapor in the cover gas

- Inspection for hydrogen to determine that any radiolysis of residual or bound water does not produce a flammable condition

- Profilometry at the completion of the storage period to determine creep deformation

- Gas G puncturingt i att completion l ti off storage t to t determine d t i cladding l ddi stress for creep calculations

- Cladding metallography at the completion of storage to determine condition of cladding hydrides h drides 5

AMP Element 4:

Detection of Aging Effects NUREG-1927: Define method or technique, frequency, sample size, data collection, and timing to ensure timely detection of aging effects

  • Surveillance demonstration program meeting ISG-24:

- Calibrated thermocouple lances to measure the radial and axial temperature profile

- Fission gas analysis technique for the cover gas with sensitivity to detect release of 1% of the fission gas produced in 1% of the cask rods with the lowest burnup in the demonstration

- Residual moisture detection technique with sensitivity to detect the vapor pressure at the bottom of the demonstration system

- Hydrogen H d d detection t ti ttechnique h i with ith sensitivity iti it to t detect d t t 2%

hydrogen in the cover gas of the demonstration 6

AMP Element 5:

Monitoring & Trending NUREG-1927: Should provide for prediction of the extent of the effects of aging and timely corrective or mitigative actions

  • As information/data from a fuel performance surveillance demonstration program becomes available, the licensee will monitor, evaluate, and trend the information via their Operating Experience Program and/or the Corrective Action Program to determine what actions should be taken to manage fuel and cladding performanceperformance, if any
  • Similarly, the licensee will use its Operating Experience g

Program and/or Corrective Action Program g to determine what actions should be taken if it receives information/

data from other sources than the demonstration program on fuel performance 7

AMP Element 6:

Acceptance Criteria NUREG-1927: Acceptance criteria, against which the need for corrective action will be evaluated; should ensure that SSC functions are maintained

  • ISG-24 acceptance criteria provide detailed guidance
  • Cask internals and fuel performance criteria:

- Temperature: spatial distribution and time history accurately determined - necessary since the behavior of the rods in the demonstration to the behavior expected of the rods in storage is temperature dependent dependent.

- Cladding Creep: total creep strain extrapolated to the total approved storage duration based on the best fit to the data, accounting for initial condition uncertainty shall be less than 1% -

ISG-11 temperature limits are based on limiting creep to <1%

8

AMP Element 6:

Acceptance Criteria NUREG-1927: Acceptance criteria, against which the need for corrective action will be evaluated; should ensure that SSC functions are maintained

  • Cask internals and fuel performance criteria:

- Hydrogen - maximum hydrogen content of the cover gas over the approved pp storage g p period shall be extrapolated p from the g gas measurements to be less than 5% - limit for precluding possible flammable mixture

- Drying y g - The moisture content in the cask , accounting g for measurement uncertainty, shall indicate no greater than one liter of residual water after the drying process is complete - Drying limit, in terms of residual moisture, in the SRP NUREG-1536

- Fuel rod breach - fission gas analysis shall not indicate more than 1% of the fuel rod cladding breaches. - Recommended maximum number of cladding breaches during normal conditions of storage for containment analysis by ISG-5 9

AMP Element 7:

Corrective Actions NUREG-1927: Corrective actions, including root cause determination and prevention of recurrence, should be timely

  • Licensee Corrective Action Program to capture and evaluate surveillance demonstration program data, other information/data, and additional operating experience to i iti t corrective initiate ti and/ord/ preventative t ti actions:

ti

- Corrective actions to prevent reoccurrence

- Extent of condition to other susceptible p components p

- Timely corrective actions 10

AMP Elements 8:

Confirmation Process NUREG-1927: Confirmation process should ensure that preventive actions are adequate & appropriate corrective actions have been completed & are effective

  • What follow up action is going to be taken to determine whether preventative or corrective actions are a success
  • Method to confirm any actions required are taken 11

AMP Elements 9:

Administrative Controls NUREG-1927: Administrative controls should provide a formal review and approval process

  • Training requirements for inspectors or personnel
  • Records retention requirements
  • Specified p in the Demonstration Project j Plan or alternate surveillance demonstration program meeting the ISG-24 guidance
  • Frequency F for f updating d ti AMP based b d on iindustry-wide d t id operational experience 12

AMP Element 10:

Operating Experience NUREG-1927: Include past corrective actions; provide objective evidence to support a determination that the effects of aging will be adequately managed so that the SSC intended functions will be maintained during the period of extended operation

  • Surrogate surveillance demonstration programs with storage t conditions diti and d ffuell ttypes similar i il tto ththose iin th the dry storage system that satisfies the ISG-24 acceptance criteria is a viable method to obtain operating p g experience p
  • DOE Dry Cask Storage Demonstration Project is viable as a surrogate surveillance program for the industry
  • Additional data/research to assess fuel performance 13

References

  • ISG The Use of a Demonstration Program as a Surveillance Tool for Confirmation of Integrity for Continued Storage of High Burnup Fuel Beyond 20 Years (ML14058B166) 14

Acronyms

  • CFR - Code of Federal Regulations
  • DOE - U.S. Department of Energy
  • ISG - Interim Staff Guidance
  • SRP - Standard Review Plan 15
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