L-16-001, Clarification to Entergys Letter: Response to Generic Letter 2016-01, Monitoring of Neutron Absorbing Materials in Spent Fuel Pools
| ML17116A055 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 04/19/2017 |
| From: | Vitale A Entergy Nuclear Northeast |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GL-16-001, NL-17-050 | |
| Download: ML17116A055 (4) | |
Text
- ==~* Entergx NL-17-050 April 19, 2017 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike, OWFN-2 FL Rockville, MD 20852-2738
/
Entergy Nuclear Northeast Indian Point Energy Center 450 Broadway, GSB P.O. Box249 Buchanan, NY 10511-0249 Tel 914 254 6700 Anthony J. Vitale President Site Vice
SUBJECT:
Clarification to Entergy's Letter: "Response to Generic Letter 2016-01, 'Monitoring of Neutron Absorbing Materials in Spent Fuel Pools"'
Indian Point Unit Number 2 Docket No. 50-247 License No. DPR-29
REFERENCES:
- 1. Entergy Letter NL-16-128, "Response to Generic Letter 2016-01,
'Monitoring of Neutron Absorbing Materials in Spent Fuel Pools',
Response to NRC Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f)", dated November 3, 2016.
- 2. NRC Generic Letter 2016-01, "Monitoring of Neutron-Absorbing Material in Spent Fuel Pools", dated April 7, 2016.
Dear Sir or Madam:
The purpose of this letter is to clarify information on page 2 of the attachment to Entergy's Letter of November 3, 2016 [Reference 1 ], in response to Generic Letter (GL) 2016-01
[Reference 2].
The corrections"are shown in "Red" in the Attachment to this letter.
This letter contains no new regulatory commitments.
Should you have any questions regarding this submittal, please contact Mr. Robert Walpole, Manager, Regulatory Assurance at (914) 254-6710.
NL-17-050 Docket 50-24 7 Page 2of2 I declare under penalty of perjury that the foregoing is true and correct; executed on April 2017.
AJV/mm
Attachment:
Page 2 of Attachment to the Entergy Letter NL-16-128 with corrections shown in red cc:
Mr. Douglas V. Pickett, Senior Project Manager, NRC NRR DORL Mr. Daniel H. Dorman, RegionalAdministrator, NRC Region 1 NRC Resident Inspectors Office Mr. John 8. Rhodes, President and CEO, NYSERDA Ms. Bridget Frymire, New York State Public Service Commission
ATTACHMENT TO NL-17-050 PAGE 2 OF ATTACHMENT TO THE ENTERGY LETTER NL-16-128 WITH CORRECTIONS SHOWN IN RED ENTERGY NUCLEAR OPERATIONS, INC. INDIAN POINT NUCLEAR GENERATING UNIT NO. 2 DOCKET NO. 50-247
Response
Minimum Certified Areal Density (Region 1) = 0.028 g-S..,10/cm2 Minimum Certified Areal Density (Region 2) = 0.022 g-s-.1 O/cm2 Nominal Design Areal Density (Region 1) = 0.0324 g-S1 O/cm2 Uncertainty in S-10 Density (Region 1) = +/-. 0.0090 g-S10/cm3 <1>
Nominal Design Areal Density (Region 2) = 0.0260 g-S1 O/cm2 Uncertainty in S-10 Density (Region 2) = +/-. 0.0094 g-S10/cm3 <1>
NL-16-128 Docket 50-24 7 Attachment Page 2of23 After a reasonable search of IP2 records, including docketed information, IPEC determined that the as built data were not part of the original licensing basis or previously requested by the NRC as part of the licensing action that approved the neutron absorber monitoring program.
- i.
material characteristics, including porosity, density and dimensions Respo.nse Materials Characteristics:
Nominal Soraflex Length: 144 in. (Region 1)
Nominal Soraflex Length: 150 in. (Region 2)
Nominal Soraflex Thickness: 0.1022 in. +/-. 0.007 in. (Region 1)
Nominal Soraflex Thickness: 0.082 in. +/-. 0.007 in. (Region 2)
Nominal Soraflex Width: 7.5 in. +/-. 0.063 in.
After a reasonable search of IP2 records, including docketed information, IPEC determined that the density and porosity was not part of the original licensing basis or previously requested by the NRC as part of the licensing action that approved the neutron absorber monitoring program.
b) qualification testing approach for compatibility with the SFP environment and results from the testing
Response
Qualification testing for the neutron absorbing material Soraflex was conducted by SISCO in the late 1970's. SISCO included tests to extremely high radiation doses, but these tests were relatively short in duration. In IP2's re-racking report of 1989, it was remarked that in published reports up to the time that Soraflex had been subjected in a reactor using the equivalent gamma dose of 2 x 1012 rads (taking credit for neutron dose). The net result was that the test indicated a substantial margin of safety against material degradation. Testing dating back to 1979 demonstrated that Soraflex is a stable "poison" material in a long-term spent fuel pool environment.
The available information in 1989 confirmed that there was no loss of boron during irradiation, although it was noticed that there was some radiation-induced shrinkage.
This shrinkage occurs as Soraflex is irradiated, in which it becomes a hard ceramic-like material. The net result is the material shrinks 2 - 2.5 %. To combat this issue for use in the Soraflex panels in the spent fuel environment, Indian Point 2 panels were installed in 1 The tolerances associated with the nominal areal density represent the volumetric uncertainties of 810 content.
Therefore, the uncertainty in B-10 concentration is+/- 0.0090 g-B10/cm3 and+/- 0.0094 g-B10/cm3 for regions 1 and 2 respectively. These tolerances ensure that at any point where the minimum B-10 concentration and minimum Boraflex thickness coincide, the B-10 areal density will not be less than the minimum certified a*real density of 0.028 g/cm2 and 0.022g/cm2 for Regions 1 and 2 respectively.