IR 05000275/2016011

Download: ML16323A110

Text

November 23, 2016

Mr. Edward D. Halpin, Senior Vice President, Generation and Chief Nuclear Officer Pacific Gas and Electric Company Diablo Canyon Power Plant P.O. Box 56, Mail Code 104/6 Avila Beach, CA 93424

SUBJECT: DIABLO CANYON POWER PLANT AND INDEPENDENT SPENT FUEL STORAGE INSTALLATION (ISFSI) - NRC INSPECTION REPORT 05000275/2016011, 05000323/2016011, AND 07200026/2016001

Dear Mr. Halpin:

On September 19-24, 2016, the U.S. Nuclear Regulatory Commission (NRC) completed a routine inspection of the dry cask storage activities associated with your Independent Spent Fuel Storage Installation (ISFSI). The preliminary inspection results were presented to Mr. Jan A.

Nimick, Senior Director of Nuclear Services, and other members of your staff onsite on September 22, 2016. Following an in-office review of your heavy loads maintenance program, the final inspection results were presented to Mr. Tom Baldwin, Site Services Director, and other members of your staff by telephone on October 27, 2016.

The inspection examined activities conducted under your license as they relate to safety and compliance with the Commission's rules and regulations and with the conditions of your license. The inspection reviewed compliance with the requirements specified in the Diablo Canyon's ISFSI License No. SNM-2511 and the associated Technical Specifications, Diablo Canyon's ISFSI Final Safety Analysis Report (FSAR), and Title 10 of the Code of Federal Regulations (CFR) Part 72, Part 50, and Part 20. Within these areas, the inspection included a review of radiation safety, cask thermal monitoring, quality assurance (QA), your corrective action program, safety evaluations, observations of dry fuel loading activities, and changes made to your ISFSI program since the last routine ISFSI inspection that was conducted by the NRC. No violations of NRC regulations were identified.

In accordance with Title 10 of the Code of Federal Regulations (10 CFR) 2.390, "Public Inspections, Exemptions, Requests for Withholding," a copy of this letter, its enclosure, and your response (if any) will be available electronically for public inspection in the NRC's Public Document Room or from the Publicly Available Records (PARS) component of the NRC's Agencywide Documents Access and Management System (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room). Should you have any questions concerning this inspection, please contact the undersigned at 817-200-1549, or Mr. Lee Brookhart at 817-200-1191.

Sincerely,/RA by RLKellar Acting for/ Lee E Brookhart, Acting Chief Fuel Cycle and Decommissioning Branch Division of Nuclear Materials Safety Dockets: 50-275, 50-323,72-026 Licenses: DPR-80, DPR-82, and SNM-2511

Enclosure:

Inspection Report 05000275/2016011; 05000323/2016011; 07200026/2016001

Attachments:

1. Supplemental Information 2. Loaded Casks at Diablo Canyon ISFSI

Enclosure U.S. NUCLEAR REGULATORY COMMISSION REGION IV Dockets: 05000275; 05000323; 07200026 Licenses: DPR-80; DPR-82; SNM-2511 Report: 05000275/2016011; 0500323/2016011; 07200026/2016001 Licensee: Pacific Gas and Electric Company Facility: Diablo Canyon Power Plant, Units 1 and 2 Location: 7 1/2 miles NW of Avila Beach Avila Beach, CA Dates: September 19 - 24, 2016 Inspectors: Lee Brookhart, RIV FCDB, Senior Inspector Eric Simpson, RIV FCDB, Inspector Accompanying Personnel: Kenneth Womack, RII DFFI, Fuel Facility Inspector

Approved By: Lee Brookhart, Acting Chief Fuel Cycle and Decommissioning Branch Division of Nuclear Materials Safety SUMMARY OF FINDINGS IR 05000275/2016011, 05000323/2016011, and 07200026/2016001; 09/19-24/2016; Diablo Canyon Power Plant and Independent Spent Fuel Storage Installation (ISFSI); Routine ISFSI Inspection Report

The report covers an announced inspection by two regional inspectors. The significance of any Part 50 findings are indicated by their color (Green, White, Yellow, or Red) using Inspection Manual Chapter (IMC) 0609, "Significance Determination Process." The cross-cutting aspect is determined using IMC 0310, "Components Within the Cross-Cutting Areas." Findings for which the significance determination process does not apply may be Green or be assigned a severity level after the NRC management review. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, "Reactor Oversight Process." In accordance with the NRC Enforcement Policy, all of the Part 72 ISFSI inspection findings follow the traditional enforcement process and are not dispositioned through the Reactor Oversight Process (ROP) or the Significance Determination Process.

A. NRC-Identified Findings and Self-Revealing Findings No findings were identified. B. Licensee-Identified Violations None. PLANT AND ISFSI STATUS Diablo Canyon Power Plant (DCPP) Independent Spent Fuel Storage Installation (ISFSI) stored forty-one Holtec HI-STORM 100SA (Short Anchored) casks at the beginning of the on-site routine inspection. DCPP was in the process of loading the 42nd canister during the routine inspection, which was the fifth canister in their current loading campaign. The licensee operated their ISFSI under a site specific Part 72 license, which utilized the Holtec HI-STORM 100 design. DCPP was loading the spent fuel in accordance with Amendment 5 to the Materials License No. SNM-2511 and the Diablo Canyon Spent Fuel Storage Installation Final Safety Analysis Report (FSAR), Revision 6. The license utilized the Multi-Purpose Canister (MPC) MPC-32 to store a maximum of thirty-two assemblies in each HI-STORM 100SA cask.

REPORT DETAILS 4. OTHER ACTIVITIES

4OA5 Other Activities .1 Operations of an Independent Spent Fuel Storage Installation at Operating Plants (60855.1) a. Inspection Scope (1) Quality Assurance (QA) Audits and Surveillances The DCPP Quality Verification Department had performed one audit of activities associated with its ISFSI since the last routine NRC ISFSI inspection in June 2015.

During that audit, the performance of the ISFSI program and its QA program implementation were assessed. The audit was documented in their 2015 ISFSI and Fuel Management Audit Report, August 17 - September 21, 2015. The audit report concluded that all areas evaluated during the assessment were satisfactory. QA reviewers identified five deficiencies during the QA audit. Those deficiencies resulted in four ISFSI related Condition Reports (CRs). CRs at DCPP are referred to as SAP Notifications or SAPNs. SAP is a problem identification and resolution computer application used at DCPP to track identified site conditions. The QA audit related SAPNs reviewed by the NRC inspectors were of very low safety significance, largely administrative in nature, involving equipment storage, personnel training/qualification tracking, and records keeping. All notifications reviewed were evaluated by inspectors to have been adequately resolved. The conditions identified were processed in accordance with Procedure OM7.ID1,

"Problem Identification and Resolution," Rev. 49. DCPP provided NRC with records for six ISFSI related QA surveillances (observations) performed by the Quality Verification Department. All of the observation records were of the Radiation Protection Office at DCPP. Five of the six documented observations were related to DCPP ISFSI activities. The sixth observation was made of activities related to PG&E's Humboldt Bay ISFSI. The Humboldt Bay ISFSI is located at a PG&E decommissioning nuclear power plant several hundreds of miles north in Eureka, CA. The QA surveillances performed at the DCPP ISFSI did not result in any condition reports. (2) Radiological Conditions Related to Stored Casks The DCPP ISFSI is located approximately 1/4 mile from the Unit-1 reactor building in the east-northeast sector of the site. The ISFSI sits at an elevation of 310 feet above sea level, 225 feet above the elevation of the reactor site (85 feet above sea level). The ISFSI was constructed into the side of a hill, which provided shielding along its south side. The DCPP ISFSI was comprised of seven rectangular 68 by 105 foot concrete pads that were designed to hold 20 HI-STORM 100SA storage casks each. The total storage capacity for the DCPP ISFSI is limited to 140 casks. The pads were aligned along their longer side and run east to west. The HI-STORM casks were anchored to the pad with studs that were threaded into embedments constructed into the 71/2 foot deep reinforced concrete pads for seismic stability.

A walk-down of the ISFSI pad was performed during the NRC inspection. The inspectors found the 41 loaded HI-STORM casks to be in good condition. No flammable or combustible materials were observed stored near or inside the ISFSI protected area. A recent radiological survey of the ISFSI pad was provided to the NRC inspectors prior to their arrival on-site. An ISFSI manager and a radiation protection (RP) technician accompanied the NRC inspectors during the pad tour. A radiological survey was performed by the RP technician with a Ludlum Model 12-4 meter with a neutron sensitive probe inside a Bonner sphere and a RadEye G Geiger-Mueller detector for gamma radiation measurements. The NRC inspector performed confirmatory gamma exposure rate measurements using a Ludlum Model 19 sodium-iodide survey meter (NRC #033906, calibration due July 13, 2017). The Ludlum Model 19 and RadEye G measured gamma exposure rates in microRoentgens per hour (µR1/h). The RP technicians Ludlum Model 12-4 measured neutron dose rates in millirem per hour (mrem/h).

Survey measurements were taken around the ISFSI pad, at selected cask lower vent locations, and at environmental TLD monitoring locations inside the ISFSI protected area fence. General area background readings before reaching the ISFSI were 5 R/hr, gamma and zero (< 0.2) mrem/hr, neutron. The observed general exposure rates increased from the edge of (empty) DCPP ISFSI Pad #7 at 7 R/hr, gamma to ~330 R/hr, gamma around the edges of (fully loaded) Pads #1 and #2. Contact measurements were made at lower vent locations for the most recently loaded casks. Those measurements were 2.5 mR/hr, gamma and 4.7 mrem/hr, neutron for a total radiation dose rate of approximately 7.2 mrem/hr. The survey measurements taken by NRC and the RP technician confirmed survey records that were provided by the licensee.

(3) Environmental Radiological Monitoring Program There were four thermo luminescent dosimeter (TLD) monitoring sites located around the ISFSI pad that were responsible for measuring the direct radiological 1 For the purposes of making comparisons between NRC regulations based on dose-equivalent (rem) and measurements made in Roentgens, it may be assumed that one Roentgen equals one rem. (http://www.nrc.gov/about-nrc/radiation/protects-you/hppos/qa96.html) impact from the loaded casks located near the ISFSI pad. The TLD monitoring locations were identified by the DCPP Area Monitoring Program as: IS-11, a monitoring location along the centerline between pad 1 and pad 2, a distance of 51 feet north of the pad; IS-12, a monitoring location located directly centerline and west of pad 2, a distance of 74 feet; IS-13, a monitoring location directly centerline between pad 1 and pad 2, a distance of 41 feet to the south of the pad; and IS-14, a monitoring location centerline and directly east, a distance of 40 feet from the pad.

In this inspection report, these TLD monitoring locations will be referred to as the direct ISFSI monitoring locations (see Figure 1, below). The TLDs used at the four direct ISFSI monitoring locations were the Mirion Type-

36 dosimeters that monitored both gamma and neutron doses at each location. Each of the four monitoring locations around the ISFSI pad included a block of human tissue equivalent material. These "phantoms" improve the neutron dose response of the TLD to that of one worn by a human standing at the each monitoring location. The gamma exposure rates at these four direct ISFSI TLD monitoring locations ranged from 70 to 150 µR/h at the time of the inspection. It was not possible to correlate the direct TLD measurements with the annual TLD monitoring data because of the recent cask loading activities and subsequent relocation of the monitoring locations. Site radiological conditions change with the addition of each newly placed spent fuel storage cask. The data showed monitoring locations IS-12 and IS-13 as posting higher yearly dose readings, on average, than locations IS-11 and IS-14 (see Table 1, below). All recently loaded spent fuel were being placed directly in the line-of-

sight of monitoring location IS-12. The dose rates are generally trending upwards as more spent fuel casks are being stored in the ISFSI. Table 1, Annual Doses in mrem for Direct ISFSI Monitoring Locations Location 2014 2015 IS-11 9051,110IS-12 1,6452,214IS-13 1,3361,870IS-14 1,2771,201 Figure 1, DCPP ISFSI Offsite and onsite monitoring data from the 2013, 2014, and 2015 Diablo Canyon Annual Radiological Environmental Operating Reports (AREORs) were reviewed (ML14127A203, ML15117A657, and ML16118A159, respectively). Those reports were generated by the DCPP Radiological Environmental Monitoring Program (REMP). The REMP included eight environmental TLD monitoring locations installed just outside of the ISFSI fence to monitor the direct radiological impacts of the ISFSI at accessible areas. The monitoring locations were identified as IS-1 through IS-8. The TLDs used for those locations were the Panasonic UD-814 model which measure only gamma dose, unlike the four direct ISFSI TLDs which measured both gamma and neutron dose. We will refer to those eight TLDs as the fixed ISFSI monitoring locations. See figure 2, below, for the locations of all onsite environmental monitoring stations with respect to the ISFSI (near center of the figure). Figure 2, DCPP Onsite Environmental Radiation Monitoring Stations2 Five of the fixed ISFSI TLD monitoring locations showed relatively elevated readings. IS-3 through IS-7 have historically been sensitive to fuel loading and storage activities at DCPP. This latest monitoring data is consistent with previous data in that regard.

2 Figure 2 is from the 2010 Annual Radiological Environmental Operating Report DCPP Table 2, Annual Doses in mrem for Fixed ISFSI Monitoring Locations TLD Identifier 2013 Total 2014 Total 2015 Total IS-1 95.1 89.4 93.6 IS-2 98.0 87.6 98.0 IS-3 136.0 126.1 168.2 IS-4 345.2 357.7 408.6 IS-5 232.8 212.7 207.5 IS-6 214.0 189.0 190.3 IS-7 150.4 133.2 154.5 IS-8 88.0 84.5 91.7 A cursory look at other TLD locations in relatively close proximity to the ISFSI pad did not show any elevated readings (see IS-1, IS-2, and IS-8, above). A selection of three TLD monitoring locations that were a bit further out from the ISFSI pad than the fixed monitoring locations were selected to see whether influences from the ISFSI extended outward to an appreciable degree. Those three monitoring locations will be referred to as the boundary ISFSI monitoring locations (see Table 3, below). Table, 3, Annual Doses in mrem for Boundary Monitoring Locations TLD # Sector/Distance Pre-ISFSI Average3 2013 Total 2014 Total 2015 Total 4S1 NE/0.5 75.6 79.5 74.4 73.7 5S1 ENE/0.4 92.0 92.2 86.6 87.0 5S3 ENE/0.7 74.4 75.3 73.0 72.4 It can be seen that all of the monitoring locations remained stable over the past several years. Overall, for the monitoring periods of 2013, 2014, and 2015, it appears that any ISFSI related elevations in dose at boundary locations were minimal based on current and pre-ISFSI average values. All monitoring results fluctuated minimally around the average historical values.

Annual radiological environmental monitoring program (REMP) data documented the dose equivalent to any real individual located beyond the site controlled area was well below the 10 CFR 72.104(a)(2) requirement of less than 25 mrem per year above background. Annual monitoring data near the ISFSI boundary locations show that all accessible areas of the ISFSI fall below the 10 CFR 20.1502(a)(1)

dose limit for unmonitored workers, which is 500 mrem per year. Direct radiation impacts from the DCPP ISFSI met all regulatory requirements. (4) Records Related to Fuel Stored in the Casks NRC inspectors reviewed the records for one randomly selected previously loaded dry fuel storage cask at DCPP to determine if the licensee could readily retrieve the documents and to access whether the documents were being maintained as required by 10 CFR 72.212(b)(12). In addition, NRC performed a review of the dry fuel storage records for 12 casks loaded at the ISFSI, since the last NRC ISFSI inspection, to determine if the selected fuel for loading into the canisters met the requirements of the license and Technical Specifications (TS). The spent fuel 3 Average monitoring location yearly value in mrem based on historical pre-ISFSI monitoring time frame from 1987 to 2008. contents of the 12 most recently loaded HI-STORM 100SA casks (including four from the current loading campaign) were recorded in three documents, Engineering Calculation RE-20150415, "ISFSI Campaign Unit 1 Portion and Insert Selection," Rev. 1; Engineering Calculation RE-20150515, "ISFSI Campaign Unit 2 Portion and Insert Selection," Rev. 2; and Engineering Calculation RE-20160725, "ISFSI Campaign Unit 1 Portion and Insert Selection," Rev. 0, respectively. These documents contained MPC loading maps and fuel assembly specific information such as qualification data, identification, decay heat (kW), cooling time (years),

average U-235 enrichment (%), burn-up values (MWd/MTU), and other information. A complete set of forms was reviewed for the last 12 canisters that were loaded and two more canisters designated to be loaded during the current campaign.

The licensee was in compliance with all applicable Technical Specifications and FSAR requirements for spent fuel stored at their ISFSI and all regulatory requirements for retrievability of cask records. (5) Cask Temperature Monitoring Diablo Canyon's ISFSI Material License No. SNM-2511, Technical Specification (TS) 3.1.2 included surveillance requirement SR 3.1.2.1, which called for the verification that all casks' inlet and outlet air duct screens were free from blockage. This surveillance was required to be performed daily for all Holtec HI-STORM 100SA casks loaded at Diablo Canyon. The licensee performed the vent inspections daily, in step 18.2.1 of Surveillance Test Procedure STP I-1A,

"Routine Shift Checks Required by Licenses," Rev. 134 required the operator to record the surveillance data on Attachment OPT-102A-1, Rev. 37. NRC inspectors reviewed documentation for (randomly selected) weeks in August and December of 2015 and in April 2016. The licensee met the technical specification requirement for the daily verification of all four vents being clear for each cask. No issues were identified with DCPP's compliance to the TS 3.1.2 vent surveillance requirement for unblocked vents. (6) Corrective Action Program A review of the Corrective Action Program associated with the ISFSI operations and the cask handling crane. A list of Notifications issued since the last NRC inspection conducted in June 2015, was provided by the licensee. Of this list, 57 Notifications were selected by the NRC inspectors for further review. The conditions identified covered a broad range of issues. Based on the range of issues identified, the licensee demonstrated a suitably low threshold for placing issues into the corrective actions program. Corrective actions and final resolution of the issues were appropriate to the safety significance of the identified issues. No significant trends were identified during the review of the Corrective Action Program. The Notifications were processed in accordance with DCPP Procedure OM7.ID1,

"Problem Identification and Resolution," Rev. 49. No NRC safety concerns were identified related to the Notifications reviewed. (7) Preparation for Loading Activities The inspectors requested documentation related to maintenance of the spent fuel building cask handling crane, the annual maintenance of the licensee's special lifting devices, the annual maintenance of the licensee's Vertical Cask Transporter (VCT) and the calibration of various gauges/instruments associated with the licensee's current loading activities.

Documents were provided that demonstrated the fuel building cask handling crane was inspected on an annual basis in accordance with the requirements of the American Society of Mechanical Engineers (ASME) B30.2, "Overhead and Gantry Cranes," prior to the 2016 loading campaign. DCPP utilized Work Order (WO) 64130793 for the crane inspection. The annual crane inspection was completed in February 2016. Diablo Canyon's ISFSI FSAR Section 4.4.1.3.1 stated: The transfer-cask-lifting trunnions and the lift yoke are designed, fabricated, inspected, maintained, and tested in accordance with NUREG-0612, "Control of Heavy Loads," to ensure that structural failures of these items are not credible. NUREG-0612 Section 5.1(4) states: Special lifting devices should satisfy the guidelines of American National Standards Institute (ANSI) N14.6.

ANSI N.14.6 Section 6.3.1 stated that each special lifting device shall be subjected annually to either load testing and a visual inspection; or if the load testing is omitted, to dimensional testing, visual inspection, and nondestructive examination (NDE) of major load-carrying welds and critical areas.

DCPP had been performing dimensional and visual inspections on its lift yoke in accordance with the ANSI standard, but had not been performing the NDE on critical areas. The inspectors found that DCPP had been following Holtec (the cask vendor) guidance that the lift yoke did not have any critical areas and that NDE of the lift yoke was not required. Holtec provided DCPP with Response to Request for Technical Information (RRTI) 2655-2 which documented the vendor's position of why no critical areas existed and as such the NDE was not required. This position to not perform NDE on the lift yoke as part of the annual maintenance was identified by NRC Region IV inspectors as differing from other Region IV sites that utilize the Holtec systems. Other sites in Region IV do perform NDE inspections on their lift yokes in accordance with the ANSI standard on an annual basis. Since this appeared to be a non-conservative approach to the NRC regional inspectors and it did not match the maintenance activities associated with other Region IV Holtec users, the Region forwarded the information regarding the applicability of NDE inspections on the lift yoke to NRC Headquarters' Division of Spent Fuel Management (DSFM) for their assistance in this review. Until DSFM completes their review of this item, it is being tracked as an Unresolved Item (URI 72-26/1601-01). Following the identification by NRC inspectors, DCPP did perform a magnetic particle NDE examination on areas of the lift yoke and found no indications or defects. The annual maintenance as required by American National Standards Institute (ANSI) N14.6 for special lifting devices was completed for the following special lifting devices (SLDs): the HI-TRAC lifting trunnions, HI-STORM lift brackets, and the MPC lift cleats. Documentation reviewed included WO 64132844 for the trunnions, WO 64135530 for the brackets, WO 64115096 for the cleats. All tested equipment passed the visual inspection, the dimensional testing, and either the magnetic particle or liquid dye penetrant inspection (NDE inspections). Diablo Canyon License SNM-2511 TS 4.3.1.c. states, the VCT shall be designed, fabricated, inspected, maintained, operated and tested in accordance with applicable guidelines of NUREG-0612. NUREG-0612 Section 5.1.1.(6) requires cranes to be inspected in accordance with ASME B30.2 and Section 5.1.1.(4) requires special lifting devices to be inspected in accordance with ANSI N14.6.

Both requirements were applicable to DCPP's VCT. The licensee completed annual and frequent crane inspections in accordance with the ASME standard on its VCT. Prior to the 2016 loading campaign the annual maintenance was completed utilizing WO 68041872 and the daily inspections were performed under Procedure PEP DF-4, Attachment 1. Special lifting device inspections were completed on the VCT's canister downloading system in accordance with the ANSI standard prior to the 2016 loading campaign. The licensee performed a proof load test followed by visual inspections on the critical welds associated with the downloading system. The work was completed under WO 68041872. (8) HI-STORM 100 Cask Yearly Maintenance The Diablo Canyon ISFSI Final Safety Analysis Report (FSAR) Section 4.4.3,

"Storage Cask Repair and Maintenance," references to Section 9.2, Maintenance Program," of the HI-STORM 100 System. The HI-STORM 100 FSAR specified the HI-STORM maintenance schedule in Table 9.2.1. Among other tasks, the schedule required an annual visual inspection of the storage cask's external surfaces and identification markings for signs of damage or degradation. NRC inspectors reviewed the documentation related to the annual visual examination of DCPP's HI-STORM 100SA casks for 2016. Those documents included WO #64132253 and included filled out copies Procedure PEP DF-12, "HI-STORM Annual Inspection," and its Attachment 9.1, "HI-STORM Annual Inspection Data Sheet." In 2016, 13 out of 37 HI-STORM over packs required some level of vent screen maintenance and several of the older overpacks experienced fading painted surfaces, including dose survey targets, lid to body alignment markings, and pad to body alignment markings. Work orders were written to address all of the noted maintenance issues. The NRC inspectors determined that the licensee's yearly maintenance activities and records met the requirements of the FSAR. The casks were also visually inspected as part of the NRC ISFSI pad tour. All casks appeared to be in good physical condition. (9) Changes to the SNM-2511 License and FSAR At the time of the previous ISFSI inspection in June 2015, DCPP was utilizing ISFSI License SNM-2511, Amendment 3 and FSAR Revision 5. At the time of the current inspection, the site was operating under License SNM-2511, Amendment 5 (ML16104A373) and FSAR Revision 6. License SNM-2511, Amendment 4 (ML105041A057), issued on January 5, 2016, provided a security related update to the license. License Amendment 5, issued April 7, 2016, removed the term preferential loading from the Technical Specifications and improved clarity and human factors usage of the Technical Specifications.

Changes to the Diablo Canyon ISFSI FSAR to move from Revision 5 to 6 were largely to reflect changes made for the implementation of ISFSI License Amendment 3 and other updates. Since FSAR, Revision 6 was submitted to NRC in March 2016, it does not include the implementation of the current License Amendment 5, which was issued in April 2016. (10) Cask Loading Observations Various loading activities were observed by the NRC inspectors during the course of the routine ISFSI inspection. DCPP was in the process of loading canister #42 at the time of the inspection. The NRC inspectors observed the fuel movement activities to place spent fuel assemblies into canister #42. The licensee's staff was experienced in moving the spent fuel assemblies and was proficient in locating the correct assembly, verifying the assembly, moving the assembly from the rack to the canister, and inserting the assembly into the assigned canister slot.

Selected welding and non-destructive examination activities were observed during the loading activities associated with canister #42. An automatic welding process was used to weld the canister lid, which utilized one weld head to weld the lid-to-shell weld. The welders operated the equipment remotely in a low dose rate area. Hydrogen monitoring was performed during the welding of the root weld through the final pass. Additionally, the NRC inspectors observed the non-

destructive dye penetrant exams conducted on the lid-to-shell weld and the welds on the vent and drain port covers. Any welding defects that were found were repaired by the welders and subsequent NDE examinations of the area passed with clear results.

Other activities that were observed by NRC inspectors during the loading of canister #42 included the hydrostatic testing of the MPC, draining of the MPC, and drying of the MPC. Inspectors observed the heavy loads operations associated with moving the HI-TRAC transfer cask/MPC from the fuel building to a low profile transporter, movement of the HI-TRAC transfer cask/MPC with the VCT to the Cask Transfer Facility (CFT), downloading operations of the MPC from the transfer cask to the HI-STORM overpack, and movement of the overpack to the ISFSI pad. The licensee's cask handling crane and VCT were able to handle the heavy loads without any observed problems. b. Findings None. .2 Review of 10 CFR 72.48 Evaluations (60857) a. Inspection Scope DCPP's 10 CFR 72.48 screenings and evaluations for ISFSI program changes since the last NRC routine ISFSI inspection were reviewed to determine regulatory compliance.

DCPP evaluated their 10 CFR 72.48 screenings and evaluations using DCPP Procedure TS3.ID2, "Licensing Basis Impact Evaluations," Revision 42. DCPP had performed a number of procedure revisions under the 72.48 process since the last ISFSI inspection. NRC inspectors reviewed the 72.48 screens for seven of those procedure changes. Additionally, inspectors reviewed the 72.48 screens associated with four design change packages made within the ISFSI program. None of the screens led to a full 10 CFR 72.48 safety evaluation. All screenings were determined to be adequately evaluated. As part of the safety review inspection scope, the NRC inspectors documented that the licensee had made no 10 CFR 50.59 screenings or evaluations associated with the fuel building cask handling crane since the last ISFSI inspection.

b. Findings No findings were identified. 4OA6 Meetings, Including Exit Exit Meeting Summary On September 22, 2016 while on-site, the inspectors presented the preliminary inspection results to Mr. Jan A. Nimick, Senior Director of Nuclear Services, and other members of the licensee staff. Following an in-office review of your heavy loads maintenance program, the final inspection results were presented to Mr. Tom Baldwin, Site Services Director, and other members of your staff by telephone on October 27, 2016. The licensee acknowledged the inspection details presented. The inspector asked the licensee whether any materials examined during the inspection should be considered proprietary. No proprietary information was identified.

Attachment 1 SUPPLEMENTAL INSPECTION INFORMATION KEY POINTS OF CONTACT Licensee Personnel K. Brasco, Engineer, Dry Fuel Management S. Flickinger, Project Manager, Dry Fuel Management R. Hagler, Supervisor, Technical Services M. McCoy, NRC Interface, Regulatory Services J. Morris, Supervisor, Regulatory Services L. Pulley, Manager, Dry Fuel Management J. Strickland, Leader, Technical Services

INSPECTION PROCEDURES USED IP 60855.1 Operations of an ISFSI at Operating Plants IP 60857 Review of 10 CFR 72.48 Evaluations LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED Opened URI 07200026/201601-01, "Applicability of required NDE inspections on the Lift Yoke in accordance with ANSI N14.6" Discussed None Closed None

A1-2 LIST OF DOCUMENTS REVIEWED The following is a list of documents reviewed during the inspection. Inclusion on this list does not imply that the NRC inspectors reviewed the documents in their entirety, but rather, that selected sections of portions of the documents were evaluated as part of the overall inspection effort. Inclusion of a document on this list does not imply NRC acceptance of the document or any part of it, unless this is stated in the body of the inspection report. 4OA5.1 Other Activities Drawings NUMBER TITLE DATE Survey 50765 MPC-389 Post Bolt Down and ISFSI Pad Annual 09/03/16 Survey 50879 MPC-388 Bolt Down and CTF RCA Release 09/10/16 DC 6021754-38-1 MPC Cleat Rev. 2 DC 6021754-39-1 Diablo Canyon HI-TRAC Lift Yoke Ancillary #702 Rev. 0 DC 6021754-32-1 Holtec Purchase Specification for HI-TRAC Lift Yoke Rev. 5 Procedures NUMBER TITLE REVISION MP M-42-DFS.1 FHB Dry Fuel Storage Rigging and Load Handling Rev. 8 OP B-8H Spent Fuel Pool Work Instructions Rev. 45A PEP DF-1 MPC and HI-STORM Preparation Rev. 2 PEP DF-2 Multi-purpose Canister (MPC) Loading Rev. 2 PEP DF-3 Drying, Backfilling, and Sealing the MPC Rev. 4 PEP DF-4 Multi-purpose Canister Transport Rev. 3 PEP DF-6 Responding to Abnormal Conditions Rev. 1 PEP DF-9 PG&E Liaison Guidance Rev. 5 IDAP DF1.ID3 Cask Transport Evaluation Program Rev. 3 PCI GQP 9.2 Liquid Penetrant Examination/Acceptance Standards Rev. 9 PCI GQP 9.6 Visual Examination of Welds Rev. 15 PI-CNSTR-T-OP-230 Closure Welding of MPCs at Diablo Canyon Rev. 7 MSLT-DSC-HOLTEC Helium Mass Spectrometer Leak Test Procedure Rev. DC-00 OM.7ID1 Problem Identification and Resolution Rev. 49 TS3.ID2 Licensing Basis Impact Evaluations Rev. 42 STP I-1A Routine Shift Checks Required by License 04/23/2014 Design Basis Documents NUMBER TITLE REVISION SNM-2511 Materials License for Diablo Canyon ISFSI Amendment 5 ISFSI FSAR DC ISFSI Final Safety Analysis Report Updated Revision 6

A1-3 Miscellaneous Documents NUMBER TITLE NUPIC 24235 Holtec International NUPIC Audit 09/30/2016 FileNet #152150011 PG&E DCPP 2015 ISFSI and Fuels Audit Report 10/01/2015 Obs. Report 15197 DC Engineering Practices 09/19/2016 Obs. Report 6558 DC Radiation Protection 05/06/2015 2014 TLD 2014 Annual ISFSI TLD Report 2014 2015 TLD 2015 Annual ISFSI TLD Report 2015 2016 TLD 2016 Annual ISFSI TLD Report 2016 HOI-068880 Calibration Record 08/11/2016 Calc 9000040833 Fuel Assembly/Cask Loading for Unit 1 Campaign 1 06/19/2012 Calc RE-20160725 Fuel Assembly/Cask Loading for Unit 1 Campaign 6 07/25/2016 Calc RE-20150515 Fuel Assembly/Cask Loading for Unit 2 Campaign 5 06/25/2015 CMTR D65-65033 Certified Material Test Reports for Embed Coupler 04/28//2006 NDE UT-2 Ultrasonic Thickness Measurement Datasheet 08/16/2016 Holtec PP DS-258 Position Paper Fracture Toughness Considerations 05/29/2014 Holtec RRTI-2665 Request for Technical Information on Lift Yoke 10/10/2016 NDE MT-1 Magnetic Particle Examination Sheet for Lift Yoke 11/16/2016

72.48 Screenings and Evaluations (PADs/ Procedure Updates) NUMBER PROCEDURE TITLE REVISION/DATE DCP 1000025285 Design Change Package Anchor Stud Length 08/17/2016 DCN 2000001651 Design Change Notice Dry Cask Storage System 08/03/2016 DCP 1000025269 Design Change Package Dry Cask Storage System 08/14/2016 DCN 2000001673 Design Change Notice Storage Pad Embedded Struc. 08/18/2016 LBIE 50872463 Gouged Shim Plate 10/01/2016 Work Orders WO 64132253 WO 64132844 WO 64125530 WO 64114004 WO 64130793 WO 68042682 WO 68041872 WO 64115096 Condition Reports 50806538 50806718 50806741 50872735 50872461 50872464 50872463 50806538 50806718 50806741 50869610 50869197 50867370 50867369 50866772 50862393 50862392 50862391 50862187 50862186 50862185 50858137 50846786 50846298 50843797 50843007 50842893 50840383 50840382 50840229 50832257 50832136 50824413 50814558 50806719 50806714 50806559 50802610 50798798 50798124 50795763 50793370 50806558 50773261 50711216 50711075 50710898 50710229 50709971 50709708 50708491 50708482 50708370 50707391 50706835 50706355 50706314 50705943 50705752 50705608 A1-4 LIST OF ACRONYMS ADAMS Agency-wide Documents Access and Management System ANSI American National Standards Institute AREOR Annual Radiological Environmental Operating Report ASME American Society of Mechanical Engineers CAP Corrective Action Program CFR Code of Federal Regulations CR Condition Report CTF Cask Transfer Facility DCPP Diablo Canyon Power Plant DNMS Division of Nuclear Material Safety F Fahrenheit FSAR Final Safety Analysis Report IMC Inspection Manual Chapter IP inspection procedure ISFSI Independent Spent Fuel Storage Installation kW killo-watt mR milliRoentgen micro(µ)R/h microRoentgen per hour MPC multipurpose canister mrem milliRoentgen equivalent man MWD/MTU megawatt days/metric ton uranium NDE Non-destructive examination NRC U.S. Nuclear Regulatory Commission PAR Publicly Available Records QA quality assurance REMP Radiological Environmental Monitoring Program ROP Reactor Oversight Program RP radiation protection SA Short Anchored SNM Special Nuclear Material TLD thermoluminescent dosimeter TS Technical Specification VCT Vertical Cask Transporter WO work order

Attachment 2 LOADED HI-STORMs AT THE DIABLO CANYON ISFSI LOADINGORDER HI-STORM ID No. MPC ID No. Unit DATE ON PAD HEAT LOAD (kW) BURNUP MWd/MTU (max) MAXIMUM FUEL ENRICHMENT % PERSON-REM DOSE 1 103 20 1 6/23/09 18.847 44887.85 4.597 0.370 2 91 12 1 6/30/09 18.915 44351.86 4.611 0.274 3 80 10 1 7/8/09 20.121 44966.91 4.406 0.313 4 102 14 1 7/18/09 20.193 44028.93 4.403 0.245 5 93 17 1 7/26/09 20.211 44717.52 4.405 0.253 6 95 21 1 8/2/09 20.256 44999.07 4.405 0.239 7 78 65 1 8/10/09 20.293 44768.81 4.403 0.196 8 100 8 1 8/17/09 19.066 44966.11 4.398 0.169 9 322 127 2 5/13/10 19.599 44863.65 4.411 0.399 10 318 123 2 5/29/10 20.101 44785.9 4.405 0.319 11 320 126 2 6/6/10 20.155 44640.73 4.414 0.199 12 317 121 2 6/12/10 20.206 44921.61 4.422 0.161 13 319 124 2 6/19/10 19.579 44841.1 4.424 0.139 14 323 120 2 6/26/10 19.632 44962.69 4.426 0.153 15 321 125 2 7/3/10 19.647 44797.98 4.427 0.122 16 316 122 2 7/10/10 19.687 44710.2 4.427 0.140 17 513 168 1 1/30/12 12.54 47682.5 4.405 0.167 18 510 167 1 2/12/12 12.71 47845.3 4.397 0.111 A2-2 LOADINGORDER HI-STORM ID No. MPC ID No. Unit DATE ON PAD HEAT LOAD (kW) BURNUP MWd/MTU (max) MAXIMUM FUEL ENRICHMENT % PERSON-REM DOSE 19 506 169 1 2/19/12 13.07 47397.8 4.397 0.104 20 514 166 2 2/26/12 12.25 46111.5 4.008 0.075 21 516 170 2 3/5/12 15.38 47194.8 4.409 0.136 22 507 165 2 3/11/12 16.03 47017.7 4.407 0.134 23 508 173 2 3/17/12 16.48 46983.4 4.407 0.129 24 632 259 1 8/18/2013 17.446 46995 4.604 0.272 25 636 256 1 8/31/2013 19.448 48113 4.405 0.225 26 638 252 1 9/7/2013 19.594 48014 4.404 0.214 27 635 250 2 9/14/2013 15.095 46946 4.423 0.121 28 641 255 2 9/21/2013 16.431 47029 4.421 0.122 29 639 251 2 9/28/2013 16.137 47269 4.407 0.124 30 640 254 1 5/5/2015 18.240 52715 4.801 0.331 31 637 175 1 5/17/2015 18.666 52722 4.407 0.331 32 634 176 1 5/24/2015 19.580 52472 4.792 0.186 33 633 257 1 5/30/2015 26.900 55813 4.946 0.411 34 512 253 1 6/6/2015 25.870 55009 4.95 0.400 35 515 258 2 6/20/2015 26.954 55680 4.953 0.376 36 509 171 2 6/27/2015 26.777 54857 4.806 0.341 37 517 172 2 7/4/2015 26.775 54976 4.947 0.365 A2-3 LOADINGORDER HI-STORM ID No. MPC ID No. Unit DATE ON PAD HEAT LOAD (kW) BURNUP MWd/MTU (max) MAXIMUM FUEL ENRICHMENT % PERSON-REM DOSE 38 511 174 1 8/18/2016 17.897 56570 4.800 0.266 39 884 381 1 8/27/2016 18.591 56096 4.947 0.217 40 886 389 1 9/03/2016 17.924 55197 4.947 0.169 41 878 388 1 9/10/2016 25.861 54911 4.951 0.382 42 885 387 1 9/25/2016 25.856 53934 4.811 0.333 NOTES: Heat load (kW) is the sum of the heat load values for all spent fuel assemblies in the cask Burn-up is the value for the spent fuel assembly with the highest individual discharge burn-up Fuel enrichment is the spent fuel assembly with the highest individual "initial" enrichment percent of U-235 Casks 1-16 Decay Heat revision reference SAPN 50453662 Casks #1 through 8 were loaded to SNM-2511, License Amendment 0, and the Updated Final Safety Analysis Report, Revision 2.

Casks #8 through 16 were loaded to SNM-2511, License Amendment 1, and the Updated Final Safety Analysis Report, Revision 3. Casks #16 through 23 were loaded to SNM-2511, License Amendment 2, and the Updated Final Safety Analysis Report, Revision 3. Casks #24 through 29 were loaded to SNM-2511, License Amendment 2, and the Updated Final Safety Analysis Report, Revision 3 Casks #30 through 37 were loaded to SNM-2511, License Amendment 3 and the Updated Final Safety Analysis Report, Revision 5 Casks #38 through 41 were loaded to SNM-2511, License Amendment 5 and the Updated Final Safety Analysis Report, Revision 6 All casks are maintained under SNM-2511, License Amendment 5, and the Updated Final Safety Analysis Report, Revision 6.