ML20216D890

IPEEEs Technical Evaluation Rept High Winds,Floods & Other External Events

ML20216D890
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Site:	Hope Creek
Issue date:	06/30/1999
From:	Hardin B NRC
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NUDOCS 9907300176
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Attachment 3 HOPE CREEK GENERATING STATION INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE)

TECHNICAL EVALUATION REPORT HIGH WINDS, FLOODS, AND OTHER EXTERNAL EVENTS (HFO)

Brad Hardin, USNRC June 1999 9907300176 990726 PDR ADOCK 05000354 P PDR I

HOPE CREEK GENERATING STATION INDIVIDUAL PLANT EXAMINATION OF EXTERNAL EVENTS (IPEEE)

TECHNICAL EVALUATION REPORT HIGH WINDS, FLOODS, AND OTHER EXTERNAL EVENTS (HFO) 1 INTRODUCTION Hope Creek Generating Station (HCGS) consists of a single unit, a General Electric BWR/4 with a Mark l containment. The plant is rated at a thermal power of a93 MWm. HCGS is owned and operated by Public Service Electric and Gas Company (PSE & d), and is located on the east bank of the Delaware River in Lower Alloways Creek Township in Salem County, New Jersey.

Salem is located on the same site. HCGS started commercial operation in December 1986.

2 SCREENING OF EXTERNAL HAZARDS Beginning with the list of external events found in the PRA Procedures Guide, NUREG/CR-2300, the HFO-related external events have been screened out either by compliance with the 1975 Standard Review Plan (SRP) criteria or by bounding analyses that demonstrate a core damage frequency (CDF) contribution of less than the IPEEE screening  !

criterion (i.e.,1E-6 per reactor year) or that the 10 CFR 100 offsite exposure limits are not exceeded. HCGS was designed as an SRP plant, and so its licensing basis conforms to the 1975 SRP criteria. The licensee used the progressive screening approach described in NUREG/CR-1407 and found that there were no plant-unique external events that pose a significant threat from severe accidents. Plant walkdowns confirmed that there were no plant changes since the issuance of the operating license that impacted on the HFO-related risk.

While the licensee determined that there were no vulnerabilities at HCGS associated with the HFO-related external events, two improvements were made as a result of the IPEEE review.

These two improvements are discussed in Sections 3 and 5 of this report.

3 HIGH WINDS The evaluation of high wind loading for HCGS was performed by comparison of the plant's design basis with SRP Section 3.3.1," Wind Loadings." The design basis wind speed for HCGS is 360 mph based on tornados having an annual frequency of exceedance of about 10#per year. The maximum wind speed of 360 mph is comprised of a rotational wind speed of 300 mph and a translational speed of 60 mph, with a pressure drop of 3 psiin conformance with Regulatory Guide 1.76. A spectrum of tornado missiles was evaluated that conformed to the SRP criteria. An evaluation was made regarding the potential for Non-Category 1 structures collapsing on or strikinn and damaging adjacant Category 1 structures with the conclusion that this was not an issue at HCGS. A walkdown was performed to evaluate hazards due to high winds, and, as a result, work was initiated to install a missile shield in front of Door 19 at the entrance to the Technical Support Center since the door was determined to be incapable of withstanding a tornado missile strike. With this improvement, it was concluded that no further significant unreviewed plant changes exist that would impact the plant hazard or licensing bases regarding high winds and tornadoes. In summary, it was concluded that HCGS conforms with the SRP criteria and that high winds and tornadoes do not represent a significant hazard.

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4 EXTERNAL FLOODS 1

The most critical combination of flood producing phenomena at HCGS results from the l postulated occurrence of the probable maximum hurricane surge with wave run-up coincident with the 10% exceedance high tide. This analysis results in a maximum wave run-up of 35.4 I

feet Mean Sea Level which could challenge some portions of the Reactor and Auxiliary Buildings and the Service Water intake Structure. HCGS safety-related systems and l components that are located below the postulated flood level are protected by enclosed reinforced concrete safety structures that are described in the licensee's IPEEE submittal.

Doors and hatches in the affected areas are either provided with a sensor to alarm in the main control room or will be administratively controlled to be closed before flood levels reach the elevation at which important systems could be compromised. The river water level is shown in the control room on a strip chart recorder and is also discernable through the plant computer. A walkdown was also performed, and it was concluded that there were no vulnerabilities due to l water ingress into safety related structures.

The licensee addressed Generic issue (GI)-103, " Design for Probable Maximum Precipitatior (PMP)," and determined that HCGS remained in compliance with the latest criteria, Roof ponding is controlled by roof design including special drainage openings on the one rectangular section of the Reactor Building. Surface flooding during the PMP was also evaluated, and it was concluded by the licensee that these challenges did not pose a hazard to the plant. Flooding from snow and ice accumulation and melt was also evaluated, and it was concluded by the licensee that snow and ice are not safety concerns for HCGS.

l 5 TRANSPORTATION AND NEARBY FACILITV ACCIDENTS The licensee evaluated aircraft impact accidents, road and rail accidents, and fixed facility accidents, including industrial facilities, military facilities, and pipeline accidents. No significant manufacturing and chemical plants, oil refineries, storage facilities, military facilities or transportation routes other than the Delaware River, or gas and oil pipelines are located within five miles of the plant.

The only major transportation route within five miles of the site is the Inter-coastal Waterway which is 1.5 miles (approximately 7900 feet) west of the site. The licensee has done an extensive analysis of river traffic hazards and concluded that the impact of an explosion on an explosive-carrying vessel at its closest point to the site in the shipping channel (about 5700 feet) would be negligible. The likelihood of an explosive-carrying ship impacting and damaging the service water intake structure was also judged to be negligible by the licensee.

In its submittal, the licensee reported that their IPEEE review did uncover an area involving a temporary increase in risk. During the review, it was discovered that some unauthorized shipments of explosives had occurred during the summer of 1996 on the Delaware River in the vicinity of the Hope Creek and Salem Generating Stations. These shipments, while limited, were not authorized appropriately by the U.S. Coast Guard, and procedures were established with the Coast Guard to prevent any such further shipments.