IR 05000387/2005007

IR 05000387-05-007, 05000388-05-007; on 06/6-10/05 and 06/20-24/05 for Susquehanna Steam Electric Station Units 1 and 2; Engineering Team Inspection

ML052160257
Person / Time
Site:	Susquehanna
Issue date:	08/04/2005
From:	Doerflein L Engineering Region 1 Branch 2
To:	Mckinney B Susquehanna
References
IR-05-007
Download: ML052160257 (12)

Text

ust 4, 2005

SUBJECT:

SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 -

SAFETY SYSTEM DESIGN AND PERFORMANCE CAPABILITY INSPECTION REPORT NOS. 05000387/2005007 AND 05000388/2005007

Dear Mr. McKinney:

On June 24, 2005, the U.S. Nuclear Regulatory Commission (NRC) completed a Safety System Design and Performance Capability team inspection at the Susquehanna Steam Electric Station. The enclosed inspection report documents the inspection results which were discussed on June 24, 2005, with you and members of your staff.

The inspection examined activities conducted under your license related to safety and compliance with the Commissions rules and regulations, and with the conditions of your license. The inspection involved field walkdowns, examination of selected procedures, calculations and records, and interviews with station personnel.

Based on the results of this inspection, no findings of significance were identified.

In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRCs document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).

Sincerely,

/RA/

Lawrence T. Doerflein, Chief Engineering Branch 2 Division of Reactor Safety Docket Nos. 50-387,05-388 License Nos. NPF-14, NPF-22 Enclosure: Inspection Report Nos. 05000387/2005007 and 05000388/2005007

Mr. Britt

SUMMARY OF FINDINGS

IR 05000387/2005007, 05000388/2005007; June 6-10 and June 20-24, 2005; Susquehanna

Steam Electric Station Units 1 and 2; Engineering Team Inspection.

The inspection was conducted by five regional inspectors and an NRC contractor. No findings of significance were identified during the inspection. The NRC's program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, "Reactor Oversight Process," Revision 3 dated July 2000.

NRC-Identified and Self-Revealing Findings

None

Licensee-Identified Violations

None ii

REPORT DETAILS

REACTOR SAFETY

Cornerstones: Initiating Events, Mitigating Systems, and Barrier Integrity

1R21 Safety System Design and Performance Capability (IP 71111.21)

a. Inspection Scope

In selecting systems and components for review, the team focused on risk significance and considered the risk information contained in the NRCs Risk Informed Inspection Notebook for Susquehanna Steam Electric Station (SSES) Units 1 & 2. Using risk insights, the team selected the automatic depressurization system (ADS) and the high pressure coolant injection (HPCI) system and their respective components for review.

The review of the automatic depressurization system included the six automatically controlled safety-relief valves installed on the main steam lines inside primary containment. The team reviewed the automatic function, by action of an electric-pneumatic control system, of these dual purpose valves. The relief by normal mechanical action is intended to prevent over pressurization of the reactor vessel. The depressurization by automatic action of the control system was reviewed because it reduces reactor vessel pressure during small and medium size Loss-of-Coolant Accident (LOCA) scenarios in which the high pressure coolant injection system is not available.

The team specifically reviewed the design capability of major risk significant components of the automatic depressurization system including the ADS valves, ADS solenoids and the ADS nitrogen supply system. This review was performed to determine if the design basis was in conformance with the licensing commitments, regulatory requirements and design output documents. Operational procedures were reviewed to determine if the procedure could be implemented given the current system configuration. These procedures were compared against lesson plans, training, and simulator use to assure the plant configuration matched to training configuration.

Regarding the high coolant pressure injection system, the team focused on the steam turbine driven constant-flow pump assembly, associated system piping, valves, controls, and instrumentation located in the reactor building. The team inspected the HPCI suction piping from both the condensate storage tank and the suppression pool. The team also reviewed the HPCI injection line into the reactor feedwater line. In addition, the team inspected the HPCI system controls, such as the remote controls for valve and turbine operation.

Since the HPCI system is provided to ensure that the reactor core is adequately cooled in the event of a small break in the reactor coolant pressure boundary which does not result in rapid depressurization of the reactor vessel, a number of high risk sequences, such as station blackout, were considered during the inspection. In addition, since the HPCI system is designed to pump water into the reactor vessel for a wide range of pressures, the team evaluated HPCI performance capability for various backpressures.

The team reviewed the design and operation of the ADS and HPCI system. Specifically, the team reviewed the design basis documents, the Technical Specifications (TS), the Updated Final Safety Analysis Report (USFAR), and the ADS valve vendor manual.

The design output documents reviewed included piping and instrument drawings. The team performed this review to determine whether the system and component functional requirements during normal, abnormal and accident conditions were met and to ensure consistency with various design documents, design specifications and control diagrams.

For both systems, the team reviewed selected mechanical calculations and analyses to verify the appropriate input assumptions were used and that the assumptions applied to the current system and plant configuration. The team verified that adequate engineering methods were utilized and the technical bases supported the conclusions.

The team also selected some design and electrical calculations, and performed independent calculations to evaluate their adequacy.

The team evaluated system environmental conditions, including the effect of various design basis accidents, to verify plant conditions were bounded by the equipment qualification assumptions. A sample of preventive maintenance activities were reviewed to verify that maintenance was performed as scheduled and that environmental qualification was being maintained. The team evaluated a sample of surveillance and pre-operational test results to verify system capability. In addition, the team chose the intermittent steam-trap alarm to focus on the two-phase flow and flow accelerated corrosion in the steam-trap drain.

The team reviewed the control wiring diagrams of ADS and HPCI to verify, for example, that pump operation, including automatic initiation, conforms with the system operation described in the updated final safety analysis report. The review included control of valves critical to the correct operation of the systems. The team reviewed both alternating and direct current power distribution to ensure that a single failure of an electrical component or source did not impair the ability of the systems to perform their safety function. The review confirmed that sufficient instrumentation was provided to initiate automatic functions and to monitor the operation of the systems during a loss-of-offsite power (LOOP).

The team reviewed the Class 1E battery load calculation to verify that required loads had been correctly identified and to ensure that the batteries were capable of meeting the load requirements under worst-case duty cycles. Since station black out is a risk significant accident scenario for both ADS and HPCI, the calculations were reviewed specifically against the Susquehanna coping scheme. The team also reviewed the direct current voltage drop calculation and sampled recent battery performance tests to verify that adequate voltage was provided to the safety-related loads during worst-case loading. The team reviewed environmental qualification of motors and valves to verify that the motors and valves would be capable of performing their required safety function.

b. Findings

No findings of significance were identified.

4OA2 Identification and Resolution of Problems

a. Inspection Scope

The inspectors reviewed a sample of corrective action reports, as identified in the Documents Reviewed section, to verify that Susquehanna Steam Station personnel were identifying issues at an appropriate threshold, entering them in the corrective action program, and taking appropriate corrective actions. Also, the inspectors evaluated corrective actions to confirm that repairs and/or modifications to components had no adverse impact on the system design basis.

b. Findings

No findings of significance were identified.

4OA5 Other

(Closed) URI 05000387;05000388/2001004-03; Inclusion of SLC Design Modifications for ATWS Rule in the Design Bases of the Plant During the March 2001 safety system design and performance capability team inspection, NRC staff identified that the Standby Liquid Control (SLC) system would not obtain the assumed flow-rate specified under the Anticipated Transient Without Scram (ATWS) Rule as defined in 10 CFR50.62. The specific postulated scenario of concern was an ATWS with Loss-of-Offsite Power (LOOP) event. Non-cited violation 05000387;05000388/2001004-02 was subsequently issued. PPL took corrective actions by implementing physical hardware changes to correct the nonconforming condition. The NRC staff also opened an Unresolved Item (URI) in order to later review PPLs conclusion regarding the functional requirement of the SLC system with respect to the ATWS rule, the applicability of TS section 3.1.7 to the ATWS Rule in this case, and PPLs decision not to report the failure to meet the requirements of the ATWS rule.

The inspectors reviewed PPLs corrective actions responding to the URI. The team reviewed condition report (CR) numbers 316309, 316780, 321640, and 548025. The team found PPLs evaluation, including their completed and proposed corrective actions to be acceptable. These included licensing bases changes, enhancements to training regarding the interpretation of the ATWS requirements with respect to design bases, and hardware and procedure changes which fully addressed the concerns of the issue.

Based on the review of the above, the inspectors considered this unresolved item closed. No violations of NRC requirements were identified.

4OA6 Meetings, including Exit

On June 24, 2005, at the completion of the inspection, the team presented the inspection results to Mr. McKinney and other members of his staff. The team verified that the inspection report does not contain proprietary information. Any proprietary information that was provided or examined during the inspection was returned to the licensee upon completion of the inspection.

ATTACHMENT:

SUPPLEMENTAL INFORMATION

KEY POINTS OF CONTACT

Licensee Personnel

M. Adelizzi, Senior Engineer - Plant Analysis

P. Brady, Supervisor - Electrical and I&C Design

D. Brophy, Senior Engineer - Nuclear Regulatory Affairs

R. Centenaro, Mechanical Design Engineering

D. Gladey, Senior Electrical Engineer

S. Kartchner, Senior Engineer - Station Engineering / ADS System Engineer

J. Krais, Manager - Nuclear Design Engineering

B. McKinney, Senior Vice President and Chief Nuclear Officer

E. Miller, Senior Engineer - Nuclear Regulatory Affairs

J. Petrilla, Unit Supervisor - Operations

J. Vandenberg, Senior Engineer - Station Engineering / HPCI System Engineer

LIST OF ITEMS OPENED, CLOSED, AND DISCUSSED

Opened

None

Closed

05000387;

05000388/200104-03 URI Inclusion of SLC Design Modifications for ATWS Rule in the Design Bases of the Plant