L-MT-13-095, Non-Compliance with Energysolutions Model 8-120B Cask Certificate of Compliance
| ML13277A608 | |
| Person / Time | |
|---|---|
| Site: | Monticello, 07109168  |
| Issue date: | 10/04/2013 |
| From: | Fili K Northern States Power Co, Xcel Energy |
| To: | Document Control Desk, NRC/NMSS/SFST |
| References | |
| L-MT-13-095 | |
| Download: ML13277A608 (6) | |
Text
Xcel Energy@
Monticello Nuclear Generating Plant 2807 W County Road 75 October 4, 2013 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Monticello, MN 55362 Director, Division of Spent Fuel Storage and Transportation Office of Nuclear Material Safety and Safeguards, Washington, DC 20555-0001 Monticello Nuclear Generating Plant Docket 50-263 Renewed Facility Operating License No. DPR-22 L-MT-13-095 10 CFR 71.95 Non-Compliance With EnergySolutions Model 8-1208 Cask Certificate of Compliance In accordance with 10 CFR 71.95(a)(3), the Northern States Power Company-Minnesota (NSPM), doing business as Xcel Energy, Inc., is providing this report documenting several instances where the conditions of approval in the Certificate of Compliance (CoG) were not followed during shipment using the U. S. Nuclear Regulatory Commission (NRC) approved EnergySolutions Model 8-1208 cask transportation package.
Summary of Commitments This letter proposes the following commitment.
NSPM will update procedures for leak testing the EnergySolutions' Model 8-1208 cask to conform to those prescribed in the current Certificate of Compliance and the cask Safety Analysis Report prior to the next shipment.
Should you have questions regarding this letter, please contact Mr. Tony Hedges at (763) 295-1682.
~/ov~
Karen D. Fili Site Vice President, Monticello Nuclear Generating Plant Northern States Power Company - Minnesota Enclosure cc:
Administrator, Region Ill, USNRC Project Manager, Monticello, USNRC Resident Inspector, Monticello, USNRC Minnesota Department of Commerce
ENCLOSURE MONTICELLO NUCLEAR GENERATING PLANT NON-COMPLIANCE WITH ENERGYSOLUTIONS MODEL 8-1208 CASK CERTIFICATE OF COMPLIANCE (4 pages follow)
L-MT-13-095 Enclosure Page 1 of 4 NON-COMPLIANCE WITH ENERGYSOLUTIONS MODEL 8-1208 CASK CERTIFICATE OF COMPLIANCE I.
Abstract This report, in accordance with the requirements of 10 CFR 71.95(a)(3),
discusses several instances in which the conditions of approval within the Certificate of Compliance (CoC) for the EnergySolutions' Model 8-1208 transportation package (Cask CoC Number 9168) were not observed in making a shipment. The circumstances described in this report are applicable specifically to the Monticello Nuclear Generating Plant (MNGP). Northern States Power Company-Minnesota (NSPM), doing business as Xcel Energy, Inc., utilized the EnergySolutions' air pressure drop test procedure TR-TP-002 to perform Model 8-1208 cask pressure testing. The test procedure specifies a 20-minute hold time for pre-shipment leak tests of the cask vent port. The Model 8-1208 cask EnergySolutions' Safety Analysis Report (SAR) however, specifies a 60-minute hold time for leak testing of the cask vent port; therefore, the conditions of approval in the CoC were not observed in making a shipment using this cask.
During the time period in which EnergySolutions' procedure TR-TP-002 was in effect (i.e., February 2001 to the present), four shipments were identified, by a review of the MNGP testing and shipping records, which may have not met the requirements of the CoCas described in more detail in Section II. These occurrences were entered and evaluated in accordance with the MNGP Corrective Action Program. A corrective action is provided in Section IV of this enclosure to resolve this issue.
II.
Narrative On August 21, 2013, NSPM personnel became aware of a letter sent by EnergySolutions, entitled, "Vent Port Leak Test Discrepancy EnergySolutions Model 8-1208, Cask Compliance Notification (NRC Certificate of Compliance
[Number] #9168)," dated June 13, 2013. The letter described a discrepancy between the minimum required hold time in Chapter 8 of the July 2012 SAR Addendum and the current EnergySolutions operating procedure. Chapter 8 of the Model 8-1208 SAR Addendum requires a 60-minute hold time for the pre-shipment leak test pressure of the primary lid, secondary lid, and vent and drain ports. Although the operating procedure requires that the leak test pressure be held for 60 minutes for the primary and secondary lid seals, it only specifies a 20-minute hold time for the vent port seal leak test pressure.
Therefore, for Model8-1208 cask shipments that were made using a 20-minute hold time for the vent port seal pre-shipment leak test, would not comply with the requirements of the Model 8-1208 cask SAR Addendum. EnergySolutions advised licensees to evaluate their specific use of the Model 8-1208 cask in
L-MT-13-095 Enclosure Page 2 of 4 accordance with the required 60-minute hold time for the vent port pre-shipment leak test to determine if a notification to the NRC in accordance with the requirements of 10 CFR 71.95 was required.
On August 21, 2013, NSPM personnel became aware of a follow-up letter dated July 2, 2013, from EnergySolutions entitled, "Clarification to Letter dated June 13,.
2013 on Vent Port Leak Test Event Discrepancy". The letter stated that "... if the cask user did not remove the vent or drain port, the test is not required by the CoC. Therefore even if the test was conducted for 20 minutes per EnergySolutions procedure, the user did not violate the Certificate of Compliance."
An EnergySolutions letter, dated August 14, 2013, provided a copy of an EnergySolutions 10 CFR 71.95 report on the Modei8-120B cask. The 10 CFR 71.95 report made by EnergySolutions determined the timeframe of the occurrence to be from February 2001 to the present. Also, the third letter provided a safety analysis performed by EnergySolutions for the cask vent port which is presented, in part, in Section Ill.
A review of MNGP shipment records identified four shipments that were performed during the specified time period.
- 1.
Shipment 04-23, shipped on July 28, 2004, indicates a pre-shipment vent port test was not performed due to the vent port not being removed during shipment preparation (TR-TP-002, Revision 14, Step 4.3).
- 2.
Shipment 07-66, shipped on December 15, 2007, indicates a pre-shipment vent port test was not performed due to the vent port not being removed during shipment preparation.
- 3.
Shipment 09-29, shipped on June 9, 2009, indicates a pre-shipment vent port test was not performed.
- 4.
Shipment 11-172, shipped on December 28, 2011, indicates that a pre-shipment vent port 20-minute test was performed prior to shipment.
The cask CoC states, "Prior to each shipment, the package must be leak tested in accordance with Section 8.2.2.2 of the application (or Safety Analysis Report)."
The Safety Analysis Report, Section 8.2.2.2, further states... "in addition, prior to shipment, the vent and drain ports shall be tested by pressurizing the volume above the respective plug and stat-o-seal anytime they have been removed during the cask loading operation". Thus, the first three of the four MNGP shipments may have violated the CoC because after possible vent port removal (by the prior cask user) the required cask vent port pre-shipment testing could not
L -MT 095 Enclosure Page 3 of 4 be verified performed. For the fourth shipment, i.e., shipment 11-172, only a 20-minute pre-shipment cask vent port test was performed versus the 60-minute test that was required.
a)
Status of Components All Model 8-1208 cask components are operating normally.
b)
Dates of Occurrences July 28, 2004 December 15, 2007 June 9, 2009 December 28, 2011 c)
Cause of Error A discrepancy was identified by the vendor between the EnergySolutions air pressure drop test procedure TR-TP-002 and Chapter 8 of the Model 8-1208 SAR.
d)
Method of Discovery This event was discovered as part of the review of all shipments with the Model 8-1208 cask completed by NSPM for the MNGP from February 2001 to the last shipment which used a Model 8-1208 cask on December 28, 2011. The requirement that a 60-minute test had to be performed if the cask user removed the cask vent or drain port, was identified during a detailed review following receipt of an EnergySolutions letter, "Clarification to Letter dated June 13, 2013 on Vent Port Leak Test Event Discrepancy," through which NSPM personnel became aware of this condition on August 21, 2013.
e)
Cause NSPM personnel did not challenge the vendor test procedure that contained the incorrect time requirement for cask vent port testing to ensure that the vendor procedure met the SAR requirement.
f)
Package Contents
- 1.
8-1208 cask shipment 04-23 contained dewatered resins.
- 2.
8-1208 cask shipment 07-66 contained dewatered resins.
- 3.
8-1208 cask shipment 09-29 contained dewatered resins.
- 4.
8-1208 cask shipment 11-172 contained dewatered resins.
L -MT 095 Enclosure Page 4 of 4 Ill.
Assessment of Safety Consequences Based on an evaluation from EnergySolutions, there is no safety consequence of performing the pre-shipment leak test of the Model 8-1208 cask vent port using a 20-minute hold time versus the 60-minute hold time that is required by the Model 8-1208 cask CoC. The required hold time varies in proportion to the test volume, if the test pressure and acceptance criterion remain unchanged. Larger test volumes require longer hold times. The test volume includes the free volume of the space to be tested and the volume of the test manifold. For the original subject Model 8-1208 cask lids, Section 4.4 of the July 2012 SAR Addendum shows the calculation basis for a 60-minute hold time. Only one calculation was presented for the large primary lid containment seal. Since the other seals have smaller test volumes, a 60-minute hold time was conservatively specified for all seals, including the cask vent port.
The SAR test volume for the primary containment seal is listed as 103.2 cubic-centimeters (cc). For the pre-shipment vent port leak test, there is no safety impact from a 20-minute hold time provided that the test volume is less than or equal to the 20/60 times the primary containment seal test chamber volume, or (20/60)*1 03.2 = 34.4 cc. The vent port test volume is equal to the combined volume of the test manifold (1 0 cc) plus a very small residual volume inside the vent port, which the total is less than 34.4 cc. Therefore, pre-shipment leak tests of the vent port performed using a 20-minute hold time are adequate to demonstrate compliance with maximum leak rate acceptance criteria, and there is no safety consequence from testing vent ports for 20 minutes instead of 60 minutes.
IV.
Corrective Actions NSPM will update procedures for leak testing of the Model 8-1208 casks to conform to those prescribed in the current CoC and SAR prior to the next Model 8-1208 cask shipment.
V.
Contact for Additional Information Should you have questions regarding this subject, please contact Mr. Tony Hedges at (763) 295-1682.
VI.
Extent of Exposure of Individuals to Radiation or Radioactive Materials None