L-15-254, Submittal of 10 CFR 71.95 Report on 8-120B Cask Certificate of Compliance Noncompliance Due to the Use of a Vendor Supplied Neoprene Gasket on the Vent Port Seal
| ML15225A465 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 08/10/2015 |
| From: | Emily Larson FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Material Safety and Safeguards |
| References | |
| L-15-254 | |
| Download: ML15225A465 (10) | |
Text
,rzm Beaver Valley Power Station P.O. Box 4 FirstEnergy Nuclear Operating Company Sipnpr~P 57 Eric A. Larson 724-682-5234 Site Vice President Fax: 724-643-8069 August 10, 2015 L-1 5-254 10 CFR 71.95 Mr. Mark Lombard, Director Division of Spent Fuel Storage and Transportation Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Washington DC 20555-0001 ATTN: Document Control Desk
SUBJECT:
Beaver Valley Power Station, Unit Nos. 1 and 2 BV-1 Docket No. 50-334, License No. DPR-66 BV-2 Docket No. 50-412, License No. NPF-73 10 CFR 71.95 Report on 8-120B Cask Certificate of Compliance Noncompliance Due to the use of a Vendor Supplied Neoprene Gasket on the Vent Port Seal.
Dear Mr. Lombard:
FirstEnergy Nuclear Operating Company (FENOC) is submitting this report pursuant to 10 CFR 71.95(a)(3) regarding instances in which the conditions of approval in Certificate of Compliance #9168 for the 8-120B Cask may not have been observed when making shipments from Beaver Valley Power Station (BVPS) Unit Nos. 1 and 2.
This report is based on a 10 CFR 71.95 report dated June 24, 2015 by the certificate holder, EnergySolutions, to the NRC which is enclosed.
The enclosed notification is applicable to use of the 8-120B cask by BVPS Unit Nos. 1 and 2. FENOC records show that BVPS Unit Nos. 1 and 2 made a total of two Class B shipments using the 8-12DB cask from September 2013 through June 2015. Shipment B-4346 was made on 12/17/2013 and shipment B-4487 was made on 3/24/201 5.
During these shipments the use of a vendor supplied neoprene gasket could have reduced the sensitivity of the vent port seal pre-shipment leak test.
EnergySolutions has replaced the subject gaskets with a modified version that does not have the potential to reduce the test sensitivity and revised the applicable test procedure.
There are no regulatory commitments contained in this submittal. Any actions discussed in this FENOC letter that represent intended or planned actions are described for the NRC's information, and are not regulatory commitments.
Beaver Valley Power Station, Unit Nos. 1 and 2 L-1 5-254 Page 2 If there are any questions or if additional information is required, please contact Mr. William C. Cothen, Manager, Regulatory Compliance at 724-682-4284.
Sincerely, Eric A. Larson
Enclosure:
EnergySolutions 10 CFR 71.95 Report on the 8-120B Cask dated June 24, 2015 cc:
Mr. D. H. Dorman, NRC Region I Administrator Mr. J. A. Krafty, NRC Senior Resident Inspector Ms. T. A. Lamb, NRR Project Manager Mr. James Harris, EnergySolutions
Enclosure L-1 5-254 EnergySolutions 10 CFR 71.95 Report on the 8-120B Cask dated June 24, 2015 (7 pages follow)
ENERGYSOLUTIONS~
June 24, 2015 CD15-0149 Mark Lombard, Director Division of Spent Fuel Management Office of Nuclear Material Safety and Safeguards U.S. Nuclear Regulatory Commission Washington DC 20555-0001 ATTN': Document Control Desk
Subject:
10 CI"R 71.95 Report on the 8-120B Cask
Dear Mr,
Lombard:
Energy~oludons thereby submits the~ attached report providing the infonriation required by 10 CFR 71.95(a)(3) for instances in which the conditions of approval in the Certificate of Compliance for the 8.120B Cask (Certificate of Compliance #9!168) may not have been observed in making certain shipments. The circumstances described in this report are applicable to approximately 235 shipments made by EnergySolutions as a licensee and user of the 8-120B3 cask over a 21 month period.
If you have any questions regarding this submittal, please contact mc at 801 -649-2109.
Daniel B, Shruin Jun 24 2015 2:58 PM Seior Vice* President, Regulatory Affairs f
Energy'Solutions LLC
Attachment:
Failure to Observe Certificate of Compliance Conditions for the 8-120B Vent Port Leak Pro.Shipment Leak Test.
cc:
Michele Sampson, Chief Spenlt Fuel Licensing Branch Pierre M. Saverot Licensing Branch 299 south.Main Street, Su to 1700O
- Fax: (501) 85Q0-2679) *wwW.OnOrgysolutlons; com
ENERGYSOLUTIONS Failure to Observe Certificate of Compliance Conditions for the 8-120B Vent Port Pre-Shipmtent Leak Test June 24, 2015
- 1) Abstract During the vent port seal pre-shipment leak rate test, a neoprene gasket that was added under the test manifold may have reduced the test sensitivity below the required value, The test manifold and gasket are not licensed packaging components. The gasket was added to the test manifold on some or all shipments to more reliably seal the manifold, saving test time and reducing personnel exposures. The amount of reduction of the test sensitivity cannot be determined lor any particular shipment due to several reasons as discussed below. The gasket may have been used on as many as 100 shipments by Energy~olutions as the licensee from September 2013 through June 2015. The condition was determined not to have significant safety consequence because the seals receive periodic helium leak testing as required by the SAR, the vent ports are only opened rarely, there is a margin of conservatism of approximately a factor of 9 on the prescribed vent port leak rate test, and there have been no observations of contamination around the vent port openings that would suggest leakage.
There will be no further tests made using the gaskets since EnergySolutions has replaced all of the subject gaskets with a modified version that does not have the potential to reduce the test sensitivity.
It is unertain whether, or by how much, the sensitivity of the vent port pro-shipment lek tests was reduced because; 1) Use of the gasket was optional-. the gasket may, or may not have been in place fbr the tests, and 2) The force with which the gasket was compressed during testing is unknown,, so it is uncertain if caused the gasket to constrict onto the head of the vent port cap screw.
- 2) Narrative Description of the Event a) Status of Components All of the 8-120]B packaging components are operating normally. The neoprene gaskets that caused the event have all be removed from service and replaced with a new manifold gasket, as discussed in (4) below.
b) Dates of Occurrences From September 2013, when pro-shipment leak tests were first performed using the neoprene gasket, to present, approximately 100 shipments were made by EnergySolutions as the licensee. Most of these shipments used the neoprene gasket to perform the pro-shipment leak rate test of the vent port.
2
ENERGYSOLUTIONS c) Cause of Error New 8-1201B lids went into service in September 2013. It was found that the manifold sometimes had problems sealing with the vent port on these new lids. EnergySolutiorn.
personnel found that adding an extra neoprene gasket helped to reduce the false test failures. Since the pre-shipment leak-rate test is performed in a radiation environment, false failures are undesirable because they increase the personnel exposure. The personnel did not realize that the gaskets had the potential to reduce the test sensitivity.
Attachmnent 1 has a detailed description of the test configuration, d) Failure Mode, Mechanism, and Effects The neoprene gasket can constrict on the head of the vent port plug cap screw when it is compressed by the bottom end of the test manifold stinger, which could reduce the sensitivity of the pre-shipment leak test, Consequently, the vent port pre-shipment leak tests performed using the neoprene gasket may not have provided the required test sensitivity of lxl 0'* ref-cm3/sec.
c) Systems or Secondary Functions Affected Not applicable.
f) Method of Discovery of the Error On Monday June 1, 2015, an 8-120B cask user identified a concern that the neoprene gasket could potentially affect the integrity of the vent port seal pro-shipment leak test.
Later that week EanergySolutions performed a bench test that confirmed that the neoprene gasket can constrict on the head of the vent port plug cap screw when it is compressed by the manifold, re~sulting in a reduction of the test sensitivity.
- 3) Assessment of Safety Consequences Pre-shipmeent leak tests of all containment seals, including the vent port, were performed prior to every shipment in acc~ordance with the requirements of Chapter 7 of the SAR. In addition, periodic and maintenance leak tests of the containment seals, using helium as the test gas, were performed after maintenance, repair, or replacement of the containment seals in accordance with the requirements of Chapter 8 of the SAR?.
The 8-120B preshfipment leak rate test criteria were sized for the large primary lid, Since the vent port has a much smaller test volume, the test speoifiation is conservative, Calculations show that the test specified in the SARt is a factor of 9 more sensitive than the lxi 0" ref-cm 3!sec required by Chapter 8 of the SAR. However, due to the uncertainties in the effects of the gasket, and the behavior of seals in series, it is not possible to confirm whether the reduction in sensitivity is offset by the test criteria conservatism.
3
ENERGYSOLUTIONS There has been no indication of any leakage from the vent port from any shipment, and therefore, no exposure of individuals to radiation or radioactive materials due to the gaskets.
It is also noted that it is unusual for the vent port seal to be opened during cask operations, in which case the previous helium leak test of the vent port seal provides added assurance of seal 'integrity.
Therefore, it is concluded that there has been no safety consequence from performing vent port pre-shipment leak tests that may not have provided the required test sensitivity of lxl 0.3 ref-cm3/sec.
- 4) Planned Corrective Actions Energy~olution.a has taken corrective actions to assure that use of the old neoprene gasket design for the vent port pro-shipment leak test is immediately discontinued.
- Energy~olutions notified all 8-120B cask users with upcoming shipments to require use ofra new procedure, in conjunction with the new manifold gasket design, fbr pre-shipment leak testing of the vent port seal on all future shipments.
- EnergySolutions designed and tested new manifold gasket design that does not constrict onto the head of the vent port plus screw when compressed, and therefore it does not reduce the test sensitivity. The new gaskets have been distributed to all upcoming shipment users. The new manifold gasket design is shown in Attachxnuent 1.
The Enegy~olutions drawing for the 8-12013 air drop manifold have been revised to include the new gasket seal, and the air pressure drop test procedure TR-TP-002 has been revised to incorporate the new pre-shipment leak test procedure for the vent port. Uise of the new procedure and the new manifold gasket will assure that the pre-shiprment leak test satisfies the required test sensitivity and that the manifold gasket is removed from the test port aftfer completing the pre-shipment leak test,
- 5) Previous Similar Events Involving the 8-120B No previous similar events have been identified.
- 6) Contact Lbr Additional Information Dan Shruma Enorgy~olutions Senior Vice President, Regulatory Affairs
($01) 649-2109
- 7) Extent of Exposure of Individuals to Radiation or Radioactive Materials None.
4
4.*
ENERCYSOLUTIONS-...
Details of the 8-120B Vent Port Leak Rat~e Test Setup The 8-120B CoC requires the package to be prepared ior shipment and operated in accordance with Chapter 7 of the SAR, and tested and maintained in accordance with Chapter 8 of the SAR.
Step 7.1.14 of the SAR, requires a pre-shipment leak test of the primary lid, secondary lid, and vent port seals to be performed in accordance with Section 8.3.2.2 prior to every shipment to assure that the containment system is properly assembled, Per Table 8-2 of the SAR, the pro-shipment leak test of the vent port is performed by connecting a test manifold to the vent port, pressurizing the seal and head of the vent port cap screw to 18 psig with dry air or nitrogen, and monitoring the pressure for at least '15 minutes to assure that it does not drop by more than 041 psig.
The pre-shipnient leak test of the vent port is a pressure drop test performed using a dedicated test manifold. The test manifold is not a part of the licensed package. It includes a stinger (shown below), an 0-ring seal that contacts the stinger and the bottom of the vent port hole, and a sleeve nut to compress the 0-ring seal. The test manifold was desigrned so that it surrounds the vent port cap screw, leaving a small gap between itself and the vent port cap scerw. The 8-120B cask fleet began to ship with a new lid design in September 2013, and operations staff noted more frequent dikiulty getting the manifold to Seal. It became desirable to find a better way to seal the bottom ofthe manifold in order to minimize operator exposure. They found that adding a neoprene gasket (also n~ot part of the licensed package) under the base of the stinger as shown below helped reduce testing time and exposure.
5
o,
l W
m J
ENJ3RGYSOLUTIONS PRIMARY LID MANIFOLD O-RING SEAL (NOT LICENSED EQUIPMENT)
VENT PORT CAP SCREW NEOPRENE GASKET - SHOWN UNCOMPRESSED (NOT LICENSED EQUIPMENT) 6
40 ENERGYSOLUTIONS Co~eiv*Aton-MdiidTestSeal The new manifold gasket design, shown below, replaces the manifold 0-ring seal aind neoprene
.gasket previously used with a neoprene gasket that fits within the notch at the base of the manifold stinger.
VENT PORT SEAL.
(,SHOWN UNCOMPRESSED)
VENT PORT CAP SCREW 7