ML20136C150
| ML20136C150 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 12/19/1985 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8601030152 | |
| Download: ML20136C150 (3) | |
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TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENN ESSEC 3,7401 SN157BLookoutPlaM[ggG p g e.
December 19, 1985
/g BLRD-50-438/85-30 BLRD-50-439/85-28 U.S. Nuclear Regulatory Commission Region II Attention:
Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Dr. Crace:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 -CALCULATED ACCIDENT RADIATION DOSE NEAR THE MECHANICAL EQUIPMENT AREA EXHAUST AIR CLEANUP UNITS IS INCORRECT -
l BLRD-50-438/85-30, BLRD-50-439/85 FINAL REPORT l
l The subject deficiency was initially reported to NRC-OIE Inspector Al Ignatonis on November 20, 1985 in accordance with 10 CFR 50.55(e) l as SCR BLN NEB 8507.
Enclosed is our final report.
If there are any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY J
. Hu am ger of Li)ensing H
Enclosure cc:
Mr. James Taylor, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Records Center (Enclosure)
Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500 Atlanta, Georgia 30339
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ENCLOSURE BELLEFONTE. NUCLEAR PLANT UNITS 1 AND 2
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CALCULATED ACCIDENT RADIATION DOSE NEAR THE MECHANICAL EQUIPMENT AREA EKHAUST AIR CLEANUP UNITS IS INCORRECT BLRD-50-438/85-30 AND BLRD-50-439/85-28 SCR.BLN NEB 8507 10 CFR 50.55(e)
FINAL REPORT Description'of Deficiency-TVA drawing 3BWO219-00-30 defines the accident radiation environment near the 3
. auxiliary building mechanical equipment area exhaust air cleanup units.- The drawing states that the integrated dose in this area is 1.4E6* rads postaccident. This value does not include doses from fission products deposited on the high-efficiency particulate air (HEPA) filters following a loss of coolant accident (LOCA). This problem was discovered on Bellefonte Nuclear Plant (BLN) during a generic review for SCR BFN NEB 8504 and NCR WBN NEB 8421 which were identified on Browns Ferry Nuclear Plant and Watts Bar Nuclear Plant, respectively. Similar analyses on the'Sequoyah Nuclear Plant 1
(SQN) had shown doses as high as 1.0E8 rads in close proximity to the HEPA filters. The SQN doses were in the range 1.0E6 to 1.0E8 within the room containing the filter system. Based on engineering judgment, it is anticipated that results in this range will be computed for the BLN filter units.
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The omission of the filter radiation contribution from the enviromental dose determination was due to a failure by design personnel to recognize the significance of the filter as a source of radiation to equipment in the area.
Safety Implications Equipment which would be affected by the error consists of safety-related equipment located within approximately 20 feet of the filter units. Beyond that distance - _as determined by the SQN analysis -- the 100-day integrated accident dose should be below 2E6 rads. Two: situations may be present:
1.
The equipment may be qualified-to the location-specific dose it will
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experience, in which case the error-is principally a documentation problem.
2.
The equipment is unqualified to the radiation environment. In this'
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case, the potential exists for the components to fail as a result of the accident and render the corresponding accident mitigation system inoperative or in a degraded performance state which could adversely affect safe plant operation.
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- Read 1.4E6 as 1.4 x 106 e
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. Corrective Action TVA will perform a postaccident radiation analysis for all of the plant ventilation filters to determine the dose to be used for equipment qualification. The revised radiation dose will be listed on the environmental drawings, and each filter area will be assessed to determine what components may be affected by the revised dose. Location-specific radiation analyses will be performed as required for components which do not appear to be qualified. Components which are not qualified tc the radiation environment will be requalified, replaced, relocated, or shielded as appropriate. All corrective action to resolve this deficiency will be completed by six months before fuel load.
The engineers involved in the original analyses are no longer in the Radiation Protection Section (RPS).
Current RPS personnel are aware of the potential for high radiation doses as a result of postaccident fission product plateout 4
- within ventilation filter systems. Since the entire scope of this deficiency has been identified for all TVA nuclear plants, no additional action to prevent recurrence is required.
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