ML19321A489

Response to Intervenor Mi Lewis Interrogatories on NUREG- 0680, TMI-1 Restart Evaluation. Related Correspondence

ML19321A489
Person / Time
Site:	Three Mile Island
Issue date:	07/18/1980
From:	Zahler R METROPOLITAN EDISON CO., SHAW, PITTMAN, POTTS & TROWBRIDGE
To:	Lewis M AFFILIATION NOT ASSIGNED
Shared Package
ML19321A483	List: ML19321A482 ML19321A489
References
NUDOCS 8007230514
Download: ML19321A489 (4)

Text

I BELATED CORRESPONDFECF O

V Lic 7/18/80 UNITED STATES OF AMERICA

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In the Matter of ) 4 $

) G l METROPOLITAN EDISON COMPANY Docket No. 50-289 '

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) (Restart) l (Three Mile Island Nuclear ) i Station, Unit No. 1) ) J LICENSEE'S RESPONSE TO INTERVENOR LEWIS INTERROGATORIES ON NUREG-0680, l "TMI-l RESTART EVALUATION" INTERROGATORY NO. SER-1 TO LICENSEE:

On Page 7-13 of AM 4 Para 7.3. 3'.1, "There is no bypass capa-bility around the filter unit."

Page 7 of Power Reactor Events Vol. 2, No. 2, March 1980, "This pressurized the ion exchanger and backed up radioactive water into the vent piping."

QUESTION:

The lack of a bypass is not investigated in the SER. What means is provided to overcome the accident sequence in the Power Reactor Events, p. 7, Vol. 2, No. 2, March 1980 and IE Cir.79-217 Will this accident sequence harm the vent header and possibly cause leaks?

RESPONSE

The interrogatory raises three distinct issues that are not directly related to one another. First, the interrogatory inquires into an occurrence at Calvert Cliffs, and asks whether such an occurrence could harm the vent header or cause leaks in the gaseous radwaste system. Second, the interrogatory inquires into various events reported in IE' Circular 79-21, and asks whether those l

. m u S ~/ Y

occurrences could harm the vent header or cause leaks in the

-gaseous radwaste system. Third, the interrogatory inquires into the lack of filter bypass capability. Each of these issues is discussed below seriatim.

(a) The following is extracted from page 7 of the NRC's

" Power _ Reactor Events, Vol. 2, No. 2, March 1980":

At Calvert Cliffs, the auxiliary building was evacuated on February 11, 1980 on receipt of gaseous radiation (Unit 1) , waste processing (Units 1 and 2), and main vent (Unit 2) alarms.

The Unit 2 No. 21 deborating ion exchanger had been open to the plant venting system in prepa-ration from (sic] transferring resin. However, its outlet valve to the volume control tank was not fully shut due to wire wrapped around the valve stem. This pressurized the ion ex-changer and backed up radioactive water into i the vent piping.

At TMI-1, the deborating demineralizer (liquid) also can be valved to the miscellaneous waste (liquid) storage tanks, which in turn can vent (gaseous) to the collection vent headers of the gaseous radwaste disposal system. However, the sequence of events at Calvert Cliffs bears no direct relation to the lack of filter bypass capability at TMI-1. The Calvert Cliffs sequence is not believed to have the potential for causing significant damage or leaks to the TMI-1 gaseous radwaste disposal system collection i

vent header. The TMI-1 plant system leak reduction program (and annual' integrated leak tests) described in Section 2.1.1.8 of the Restart Report specifically include the miscellaneous waste stcr-age tanks,-gaseous radwaste disposal system, and collection vent

-headers (Table 2.1-4). Moreover, the gaseous radwaste disposal

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system is provided with pressure relief capability to avoid over-pressurization and leakage. Ir the event of a leak, airborne process material from the gaseous radwaste-disposal system (and other systems and components located in the Auxiliary and Fuel Handling Building) will be filtered by the Auxiliary and Fuel Handling Building ventilation systems. It is for this reason that such ventilation systems should not be bypassed.

(b) With reference to IE Circular 75-21 (such circulars do not request that a response be submitted to the NRC), Section 2.1.1.8 of Licensee's Restart Report describes the following "means for overccming the accident sequence":

[R]eview and inspection of release paths, as identi-fied in IE Circular 79-21 and exemplified by the North Anna Unit 1 incident, were conducted. No modifications to existing systems and/or equipment were deemed to be necessary as a result of this review. There were, however, some minor mainten-ance items identified, such as the need for instal-lation of additional pipe caps or blanks on the downstream side of some system vent. drain, or test isolar. ion valves. These corrective measures will be completed prior to restart of TMI Unit 1.

(c) As explained in subsection (a) above, the Auxiliary and Fuel Handling Building ventilation systems are designed so that all air. flow under both normal and accident conditions would pass through the filters. This assures that air flow will always be filtered prior to release to the environment. Since charcoal and high efficiency particulate air (HEPA) filters degrade with use, the lack of a filter bypass could result in a shorter service life for the replaceable filter components. Amendment 55 to the TMI-l

Technical Specifications, issued by the NRC on June 10, 1980, re-quires periodic testing of the Auxiliary and Fuel Handling Build-ing filter system components to maintain high filter efficiency.

INTERROGATORY NO. SER-2 TO MED-ED:

Page 8-32, "The Licensee, however, has not yet provided leak-age measurement procedures to be used in the program." How can the Licensee establish "as low as practicable" when Licensee does not yet have a program in place to achieve this goal? Give defi-nite goals and timetables in your answer by which the leakage reduction program will proceed. Will this leak reduction program attempt to find the causa sine qua non for the 6 leaks in piping and 5 flange leaks an[d] 1 valve body leak in LIC 6/10/80 supple-mental response?

RESPONSE

Licensee's Restart Report describes a three-phase leak reduc-tion program (Section 2.1.1.8) . Phase I of this program includes the development of leakage measurement procedures. Work on the program continues, and Phase I is currently scheduled to be com-pleted within two months.

The six leaks (consisting of five flange leaks and one valve body leak) described in Licensee's supplemental response of June 10, 1980, are all located at TMI-2. As indicated in the supple-mental response, " Testing at TMI-l has identified no leaks in that Unit." The TMI-l leak reduction program is not intended to identify leakage or causes of leakage at TMI-2.

Respectfully submitted, SHAW, PITTMAN, POTTS & TROWBRIDGE By:

Robert Zahler Dated: July 18, 1980

_. . . .