ML20136E729
| ML20136E729 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 10/31/1985 |
| From: | Hufham J TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-85, REF-PT21-85-495-000 PT21-85-495, PT21-85-495-000, NUDOCS 8511210567 | |
| Download: ML20136E729 (3) | |
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TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 374ot 400 Chestnut Street Tower II BSNPV 7 n10: 05 Ock.ober 31, 1985 BLRD-50-438/84-38 BLRD-50-439/84-35 U.S. Nuclear Regulatory Conunission Region II Attn:
Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Dr. Grace:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 -DEFICIENT CATALYST BED IN CONSIP, INCORPORATED, HYDROCEN ANALYZERS - BLRD--50-438/84-38. BLRD-50-439/84 REVISED FINAL REPORT The subject deficiency was initially reported to NRC-0IE Inspector P. E. Fredrickson on May 18, 1984 in accordance with 10 CFR 50.55(e) as NCR BLN NEB 8412. This was followed by our interim report dated June 19, 1984 and final report dated November 28, 1984. Enclosed is our revised final report.
We consider 10 CFR Part 21 applicable to this deficiency.
The revision of the date for completion of the corrective action was discussed with NRC-0IE Region II Inspector Al Ignatonis on October 3, 1985.
If you have any questions, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours.
TENNESSEE VALLEY AUTHORITY j.a. bmt
. W. Hufham, Manager LicensinS and Risk Protection Enclosure ec:
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 8511210567 85 PDR ADOCK 0 38 pg S
An Equal Opportunity Employer
ENCLOSURE BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 DEFICIENT CATALYST BED IN CONSIP, INCORPORATED, HYDROGEN ANALYZERS BLRD-50-438/84-38 BLRD-50-439/84-35 NCR BLN NEB 8412 10 CFR 50.55(e)
REVISED FINAL REPORT Description of Deficiency It has been identifed that the containment hydrogen analyzers catalyst beds on Bellefonte Nuclear Plant (BLN) units 1 and 2 may have a limited or diminished useful life. This is due to poisoning by fission-fragment iodine
,in a post-loss of coolant accident (LOCA) containment atmosphere. The hydrogen analyzers and catalyst beds were manufactured by Comsip, Incorporated, Whittier, California (Consip). This deficiency was discovered from thermodynamic calculations performed by Comsip and others. These calculations utilized a larger post-LOCA containment fission-fragment iodine concentration (as high as 0.02 mm mercury) than was earlier assumed. Comsip estimated that the effective catalyst bed life may be as short as ten days. TVA was notified of this condition by NRC IE Information Notice 84-22 and by Comsip's 10 CFR 21 notification. This deficiency was caused by an assumed value for fission-fragment lodine concentration which may have been too low in some cases.
Safety Implications The containment hydrogen analyzers are used to detect the presence and concentration of the post-LOCA containment atmosphere hydrogen concentration.
This information is used by the control room operators to manually operate the hydrogen recombiners and/or the hydrogen purge system as described in the BLE FSAR section 6.2.5.
The deficiency, if not corrected, could result in an inaccurate hydrogen gas analyzer reading following a LOCA. This could allow the hydrogen gas concentration in containment to exceed allowable limits (which could result in combustion or detonation of hydrogen gas) due to operator inaction.
Combustion of hydrogen inside containment possibly could adversely affect the operation of essential safety-related equipment, result in doses to plant personnel greater than 10 CFR 20 limits, or result in offsite doses greater than 10 CFR 100 limits.
Corrective Action The existing containment hydrogen analyzers catalyst beds will be removed and replaced with catalyst beds of new configuration. This work will be performed per engineering change notice (ECN) 3140. The new catalyst beds are designed to function in a post-LOCA containment atmosphere and have shown no degradation after five months of continuous testing. The new catalyst beds are
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manufactured by Comsip. The use of these new catalyst beds will assure that the hydrogen gas analyzers can provide accurate post-LOCA containment hydrogen concentration information for a period exceeding 100 days. One-hundred days of post-accident operation is required by TVA's Office of Engineering calculation NEB 831227 201.
To prevent recurrence of this deficiency, Comsip initiated testing to gather empirical data regarding fissien-fragment iodine production in a post-LOCA containment atmosphere. This new catalyst bed is the result of the Comsip testing. No further action to prevent recurrence is required.
After the submission of the final report on this deficiency TVA was apprised by Comsip that the replacement catalyst beds may be poisoned by exposure to compounds of sulphur or halogens. Therefore, TVA will not install the replacement beds until approximately six months before fuel load for each unit.
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