IR 05000062/1993005

Insp Rept 50-062/93-05 on 931129-30.No Violations Noted. Major Areas Inspected:Licensee Program to Repair & Seal Concrete Adjacent to Gate Around Large Access Facility in Reactor Pool

ML20059C067
Person / Time
Site:	University of Virginia
Issue date:	12/20/1993
From:	Blake J, Lenahan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20059C052	List: IR 05000062/1993005 ML20059C051
References
50-062-93-05, 50-62-93-5, NUDOCS 9401040351
Download: ML20059C067 (4)

Text

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UNITED STATES f# a nrog% NUCLEAR REGULATORY COMMISSION i

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"t REGION 11

E 101 MARIETTA STREET, N.W., SUITE 2900 a

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Report Nos.: 50-62/93-05 Licensee: University of Virginia Charlottesville, VA 22901 Docket Nos.: 50-62 License Nos.: R-66 Facility Name: University of Virginia Reactor (UVAR)

Inspection Conducted: November 29 - 30, 1993 Inspector: /4/co//>

J. J. Lenahan/ p' Date Signed

Accompanying Personnel: E. J. McAlpine Approved by: , / 2e 3 J. J. B1 Keg Chief Date Signed Materi gnd Processes Section Engine ring Branch Division of Reactor Safety SUMMARY Scope:

This special, announced inspection was conducted in the areas of the licensee's program to repair and seal the concrete adjacent to the gate around the large access facility in the reactor pool. The repairs were required due to an unidentified leak which was estimated at approximately 100 to 150 gallons per da Results:

In the areas inspected, violations or deviations were not identifie PDR G

ADOCK 05000062 pay

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REPORT DETAILS Persons Contacted Licensee Employees

• P. Benneche, Reactor Administrator J. Brenizer, Member, Reactor Safety Committee

• P. Farrar, Reactor Supervisor -

• R. Mulder, Director, University of Virginia Reactor (UVAR) Facility A. Reynolds, Chairman, Reactor Safety Committee Other licensee employees contacted during this inspection included operators, technicians, and administrative personne Other Organizations '

W. Dickinson, Polymer Representative, Furmanite

• Attended exit interview Repairs to Reactor Pool Background In late August the licensee noted an increase in the quantity of makeup water necessary to maintain the water level in the reactor pool. The licensee estimated the increase in makeup water to be approximately 100 to 150 gallons per day. The quantity of " normal" makeup water is difficult to estimate with any certainty, since it depends on -

temperature and humidity conditions in the building housing the reactor pool, weather conditions, the temperature of the water in the reactor pool, and reactor operating condition In September, the licensee noticed a small quantity of water leaking around the outside of one of the large access facilities at the bottom of the reactor pool. This seepage, which flowed into a floor drain, was estimated to be one to two gallons per day. The licensee re-examined-their make up water data and concluded that the seepage was caused by a leak from the pool, and that this leak was part of an unidentified.-

quantity of leakage of 100 to 150 gallons per day. The licensee concluded that the unidentified leakage was seeping into the building foundation, which flows into a pond down hill from the building. The .

licensee has been monitoring the pond since the leakage was identified to ascertain that no radioactive materials were leaking into the pon The licensee retained an outside contractor to attempt a repair on the pool leak. The inspector observed the repair activities, reviewed the '

licensee's 50.59 analysis, and reviewed the licensee's data for pool level makeup and estimated leakage quantities. Details of the -

inspection follow belo ,

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2 Observation of Repair Activities The inspector witnessed the repairs to the concrete adjacent to the gate for the large access facility from which seepage was identified. The repair method, which is proprietary, involves drilling of holes in the concrete and injecting a water-activated polymer material into the concrete to seal any cracks in the concrete. Prior to start of repairs, the contractor discussed the repair method with the licensee and discussed in general terms the spacing and diameter of the drill holes, and the expected depth of the holes. The licensee limited the depth of the holes to 12 inches, so that the pool wall would not be breache The thickness of the pool wall is 18 inches, so the 12 inch deep limit resulted in a minimum remaining pool wall thickness of six inches under the bottom of each drill hole. The inspector witnessed the drilling of each hole in the concrete in the pool wall. The inspector verified that the contractor had marked the drill bits to limit the hole depth to the stipulated maximum of twelve inches. The maximum drill hold depth was usually lli inches or less. The inspector also witnessed injection of the polymer material and the cosmetic repairs to the concrete to seal the drill holes and to patch other defects in the concrete around the large access opening. Approximately four hours after the repairs were completed, the inspector examined the pool wall around the large access opening and noted that the concrete appeared to be dry. Prior to the repairs, the concrete in this area had been damp. The inspector verified that licensee personnel maintained constant communications between the reactor operating deck and the site of the repairs, which was twenty-six feet below the operating deck. The communication were maintained using two-way radio .3 Review of Fuel Pool Data and 50.59 Evaluation The inspector reviewed the licensee's 10 CFR 50.59 analysis for the reactor pool leak repair. The analysis described the repair method and addressed the consequences of the repair method on the operation of the-reactor. The inspector concluded that the analysis met the requirements of 10 CFR 50.59 and the licensee's QA/QC program. The inspector also reviewed the minutes of the November 22, 1993 Reactor Safety Committee (RSC) meeting which approved the leak repair method. Review of the minutes disclosed that the RSC appeared to limit the. maximum depth of the drill holes to six inches. However, discussions with the facility director and two members of the RSC disclosed that the RSC specified that the holes could be no deeper than 12 inches, so as to maintain a minimum wall thickness of six inches. The RSC meeting minutes will be amended to clarify the committee's intend regarding maximum drill hole dept .

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3 t The inspector also reviewed the licensee's data for reactor pool makeup water added to the reactor pool since June 1,1993, and the records of reactor pool level reading obtained November 17 through the inspection date. This data gives an indication of the unidentified pool leakag The licensee uses a figure of 240 gallons for each inch of drop in pool 7 level . The inspector performed two independent calculations and ,

determined this figure was slightly conservativ .4 Conclusions After the initial repairs were completed, the quantity of leakage appeared to decrease. However, subsequent to the inspection, the '

licensee noticed a slightly wet area in the pool wall adjacent to the gate. The contractor returned to the facility and performed additional :

repairs. After the repairs were completed, the licensee indicated that their data for pool makeup water shows that the quantity of leakage has been reduced considerabl '

No violations or deviations were identifie . Exit Interview The inspection scope and results were summarized on November 30, 1993, with those persons indicated in paragraph 1. The inspector described-the areas inspected and discussed in detail the inspection result Proprietary information is not contained in this repor I