ML20106B141

Responds to NRC Re Violations Noted in Insp Repts 50-259/84-12,50-260/84-12 & 50-296/84-12.Corrective Actions:Steps Taken to Avoid Excess Water in Resin Liner Shipments

ML20106B141
Person / Time
Site:	Browns Ferry
Issue date:	08/17/1984
From:	Lambert D TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20106B139	List: ML20106B141 ML20106B144
References
NUDOCS 8410230003
Download: ML20106B141 (7)

Text

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TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 37401 Tower II g 0 g g nug t,ree August 17, 1984 U.S. Nuclear Regulatory Commission Region II ATTN: James P. O'Reilly, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323

Dear Mr. O'Reilly:

Enclosed is our supplemental response to R. C. Lewis' May 2, 1984 letter to H. G. Parris regarding our June 4, 1984 response to Inspection Report Nos. 50-259/84-12, 50-260/84-12, 50-296/84-12 for the Browns Ferry Nuclear Plant. This response provides supplemental information for Violations 1 and 2 as requested in your May 2 letter. A two-day extension to August 17 was discussed between Ross Butcher of your staff and Mike Hellums of my staff on August 15, 1984. If you have any questions, please call Jim Domer at FTS 858-2725.

To the best of my knowledge, I declare the statements contained herein are complete and true.

Very truly yours, TENNESSEE VALLEY AUTHORITY D. L. Lambert Nuclear Engineer Enclosure 0410230003 841003 PDR ADOCK 05000259 a

PDR An Equal Opportunity Employer

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A SUPPI,53GNrAL'AESPONSE b

~NRO INSPECTION RE90RT NOS.-

50-259/ 84-12, 50-260/ 84-12,* AND 50-296/ 84-12,

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RICHARD C. LEWIS' IEWGt TO H. G. PARRIS

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' - DATED MAY 2',1984

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i Snoolemental Resnonse Reanest (1):

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'Correstive actions whidhave been and will be taken to avoid further

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violations of excess water in resin liner shipments, including test results

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obtaiwd or tests planned (o ensure that your dowatering procedures are effective. and yost administrative controls to ensure that resin loading I

conforms to the test parameters.

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. Correctives 3 tens Which Will Be Taken to Avoid Further Violations

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Section 9Nof the Final Safety Analysis Report (FSAR) provides a general

, description of the Browns Ferry solid radwaste system.. Specific operational details reqsired to meet the safety design basis are omitted. Important in

,, these specific details is the correct connection and sequencing of liner filter' elements during the dewatering process. The multiple layers of filters

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internaI'to a liner are connected to a common vacuna pump. Water is extracted s

from the Assin' slurry in the;11ner until vacuum is broken. Then the next lower filter elements are valved'Ito the pumpsand dewatering continues. The f

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dowatering process is terminated when vacuum'is broken on the bottom layer of i

fliter elements. \\

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s An extensive any'stigatJon was conducted in[o the cause for the excess water e

discovered in two zasin liners in;0ctober-1953. Plant engineering and j

operating peyspaae1 \\eviewed the theories:resulting from the investigation.

The most planelblo thsory was that procednrat and administrative deficiencies resulted in fine 1 Yews'tering from a filtff element layer other than the bottcm. Liner hote osanections were not nalformly and clearly labeled and g

I operating-Anstructions were not explic.it is requiring final dewatering from

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4he bottom. Final dowatering from any other filter layer would leave a substantin quantity of water at the bottom of the liner at the time of l

shipmenQ The similar;,czce9 quantities of water found in the two liners (95 and 100 asilons) supports this theory.

Compounding these problems was the I

feat 'that Browns Ferry :M not have an effective quality control (QC) program to check the adequacy of de.,nering.

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,Another theory was formulated at the same time attributing the incident to mixing bead and powdered resin. The basis for this theory is that bead resin j

and powdered resia dewater differently.

Powdered, resin can be vacuum dewatered quickly and efficiently. The sus 11 particle size allows capillary action to draw water to the filters from great distan es.

Bead resta does not vacuum dewater "efflaiently. The large particle size supports gravity draining as opposed to capillary action. Because of this, when vacuum is broken there is no assurance that allithe water has been removed from tend resin that is not lamediately a'djacent to the filtergement.

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Bcth liners fcund to ec:tcin orsoss w tcr vero thscrizsd to coztain high e: centraticas of bacd rasin. Prict t,o shipeszt, ths oxact compositica of bead resin in both liners was not known. The concentration of bead resin in the liner returned to Browns Ferry was determined to be 20 to 25 percent.

Operating practice at Browns Ferry has been to mix bead and powdered resin in phase separators prior to filling liners. Subsequent QC tests ha~e indicated that liners can be successfully dewatered with bead resin concentrations up to 45 percent. To produce almost identical quantities of excess water (95 and 100 gallons), the bead resin concentration in each liner would have had to be in excess of 45 percent and identical. The theory that bead resin is responsible is highly improbable.

The experience and training of the operating personnel involved in the filling and dewatering of the two liners was investigated and determined to be -

adequate.

Our corrective action was to immediately label all waste package hose connections in a uniform and permanent manner. The radwaste operating instruction was revised to include detailed steps outlining the proper sequencing of liner filters during vacuum dewatering.

A QC program was established to periodically check the adequacy of dewatering.

Because of concern over the possibility of filling a liner with only bead resin, laboratory personnel were instructed to notify operations whenever a visual examination of a resin sample was found to contain an excessive concentration of bead resin. Those liners suspected of having an elevated concentration of bead resin were conservatively lef t under vacuum for an additional two hours. Recently a technique has been perfected to quantitatively determine the actual percent bead resin present in a liner.

The highest concentration of bead resin found in a liner using this technique is approximately 45 percent.

Twelve hours af ter termination of vacuum dewatering, this liner was again subj ected to vacuum. The resulting quantity of water extracted from the 45 percent mixture was less than that allowed by burial ground criteria. Liners

.th lower concentrations of bend resin had been successfully tested previously.

Because of concern over the concentration of bend resin in our liners, we plan to continue to make quantitative determinations on the amount of bead resin in liners loaded from phase separators having mixtures of bead and powdered resin.

If a concentration of bead resin is determined to be in excess of that previously tested for adequate dewatering, then that liner will be tested independent of QC frequency requirements.

It is felt that this additional corrective action will help ensure that the safety design basis for the solid radwasto system will be maintained.

Supplemental Resnonse Reauest (2):

10 CFR 50.59 evaluation of the change to the radioactive waste system concerring mixing of bead and powder resins, which is not addressed in the FSAR.

O Additions! Information for Consideration on 84-12-02 Section 9.3 of the FSAR contains both a written description of the solid radwaste system and a f.1 ow drawing ( figure 9.3-1 A). This figure agrees with the text and shows both bead and powdered resin slurries being routed to the common waste packaging area.

The figure contains small details such as hose connections, flush lines, and liner internals no; mentioned in the text.

Just occause these details are not mentioned in the text does not lessen their impor t a nce, nor does it prohibit their use in meeting the systems design basis.

It i s Browns Ferry's use of these small details that require further clarification.

Attachment A is a copy of figure 9.3-1 A marked to show how plant personnel attached a reinforced rubber hose to transfer bead resin to waste phase separators

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It is clearly evident that the connection was made through a flush line and flow was in a direction opposite to that sh own.

This configuration is still in use and is pre f erred by plant personnel. Because the f ree er.d of the hope can only reside in one phase separator at a time, administrative control over bead resin mixing is maximized.

Attachment B is a copy of figure 9.3-1A marked to show the use of permanently installed hose connections to route bead resin from the spent resin packaging outlet to a common line leading to all six waste phase separators (A - F).

The arrangement shown on attachment A was not evaluated to determine if en unreviewed saf ety que stion (10 CFR 50.59 evaluation) existed at the time of installation.

Once plant personnel tscame aware of this oversight, a 10 CFR 50.59 evalua tion wa s perf ormed.

The key f actor in performing the 10 CFR 50.59 evaluation was that the final resul+ f rom using the configuration shown in attachment A is the same as from using the approved configuration shown on attachment B.

Our evaluation was further confirmed in a memorandum from TVA Engineering Design that states:

The de sign of the radwaste system did not preclude mixing of bead resin and powdered resin in a liner prior to disposal.

An existing hose connection also allows upstream mixing in the phase separators.

The reasons for transferring bead resin to the phase separators and for mixing the resin types is explained in our original reply.

These reasons result from operating experience gained after the FSAR was completed.

The design of the solid radwaste system allows liners to be filled with either bead resin, powdered resin, or combinations of the two.

The liners and dewatering equipm ent see common for all types of filter material handled by the solid radwaste packaging syrtem.

Plant personnel using the installed equipment have the responsibility of meeting all federal and burial ground criteria.

Specific operating details and administrative controls necessary to meet these requirement s are contained in plant procedures not in the FSAR. This allows the flexibility 'o change these instructions based on experience and to reflect changes in regulations.

For instance, operating experience has demonstrated that the proper connection and sequencing of liner filter e

elements during the dewatering is important to meet the safety design basis.

Operating experience has also demonstrated the need to exercise the option to transfer bead resin into the phase separators.

The need for an unreviewed

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p cefoty questica datsreinatica is dependelt es tho details cf the pr pos:d

' changes..In this particular case, we believe that mixing of the resin types is within the scope of the FSAR description, and that an unreviewed safety question determination was not required.

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