ML19269E558

Requests Radiological Tech Specs Be Revised to Allow Personnel Access to Deinerted Drywell for Insp & Probable Repair of Defective Transient Incore Probe Guide Tube.Repair Work Will Take Place During June Plant Shutdown

ML19269E558
Person / Time
Site:	Cooper
Issue date:	06/21/1979
From:	Pilant J NEBRASKA PUBLIC POWER DISTRICT
To:	Ippolito T Office of Nuclear Reactor Regulation
References
TAC-11856, NUDOCS 7906290281
Download: ML19269E558 (4)

Text

. -

GENER AL OFFICE Nebraska Public Power District

" fEfh2EL" Mime"^ ""

June 21,1979 Director, Nuclear Reactor Regulation Attn: Mr. Thomas A. Ippolito, Chief Operating Reactors Branch No. 3 Division of Operating Reactors U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Expedited Change to Radiological Technical Specifications Cooper Nuclear Station NRC Docket No. 50-298, DPR-46

Dear Mr. Ippolito:

In acccrdance with the provisions specified in 10CFR50.90, the Nebraska Public Power District requests that the Radiological Technical Specifications for Cooper Nuclear Station be expeditiously revised to allow plant operation with containment atmosphere oxygen concentration greater than 4% by volume and no drywell-st ppression chamber differential pressure for one 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> period between the dates of June 22, 1979 and July 25, 1979.

This Technical Specification change is necessary to safely allow personnel access to tne de-inerted drywell for inspection and probable repair of a defective TIP guide tube. A preliminary determination by the CNS plant daff indicates that a TIP guide tube has become unfastened between the LPRM and the TIP indexer.

The addition of the following Radiological Technical Specifications is requested:

3.7.A.5.e The specifications of 3.7. A.5.a thru d are not applicable during one select 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> continuous period between the dates of June 22, 1979 and July 23,1979.

3.7.E.3 The specific 6t!ons of 3.7.E.1 and 3.7.E.2 are not applicable during one select 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> continuous period between the dates of June 22, 1979 and July 23,1979.

The following addresses concerns raised by the Staff during preliminary discussions relating to these expedited Technical Specification changes:

2146 084 7 0062902gj

Mr. Thomas Ippolito June 21,1979 Page Two NEED FOR TECHNICAL SPECIFICATION CHANGE AND REASONS FOR EXPEDITING The requirement of a plant shutdown to perform the drywell entry would offer the added risk of equipment malfunction due to the strain placed on the plant during shutdown and startup.

If the repair of the problem requires a forced shutdown of the plant for reasons such as obtaining parts, etc., it is far more advantageous to be shutdown in June rather than during the peak load period in mid-July.

Presently weather conditions in the midwest make the weekend of June 23 the opportune time, from the standpoint of load requirements, to reduce power and perform the drywell entry. The repair must be completed before mid-July when a control rod pattern change requires the use of the defective TIP guide tube. A plant shutdown in mid-July to perform the repair would have a significant impact on the generating capabilities for Nebraska Public Power District.

As can be seen from NPPD Annual Operating Reports, CNS supplies a significant portion of the generating capabilities available to NPPD. A plant shutdown for purposes of repair would require approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> off line and a resulting loss of greater than two effective full power days of operation. This is a significant economic penalty in terms of replacement power costs.

Although the preliminary determination is that only one TIP guide tube is unfastened, prudent operating practice dictates that an inspection be made at the earliest possible time to completely assess the situation.

SAFETY CONSIDERATIONS CNS has a backup means of hydrogen control in the event of a LOCA during the 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> time period. Although the ACAD system is not licensed to operate, the CNS plant operating staff is familiar with ACAD system operation. The capability of the ACAD system to control hydrogen throughout the entire course of any accident was demonstrated in our transmittal of April 5,1976.

The probability of a LOCA occurring during the 48-hour period is extremely remote; however, power will be reduced to approximately 40% to significantly reduce the severity of any accident. Present Technical Specifications allow de-inerting and lack of a drywell- suppression chamber differential pressure for a total of 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> during and after a shutdown, and the time period requested by this change presents no additional safety hazard.

2146 085

. s Mr. Thoinas Ippolito June 21,1979 Page Three As stated in our January 4,1979 letter in response to the Staff's letter of November 29, 1978, a review has shown that the containment purge isolation valves (24") are capable of closing against the dynamic forces of a LOCA.

Approved plant procedures govern personnel access to the primary containment under circumstances such as this evolution.

The dose rate in the area where the repair is expected will be approximately 100-200 mrem /hr. The actual inspection and repair is anticipated to take less than a few hours.

The safety significance of this proposed change has been reviewed by appropriate District personnel, and under 10 CFR Part 170, these changes are judged to be a Class III amendment. Payment in the amount of $4,000 is enclosed with this submittal.

Should you have any questions or require additional information, please contact me.

In addition to three signed originals, 37 copies of the proposed changes are also submitted.

Sincerely yours,

\k 0 M. Pilant Director of Licensing and Quality Assurance JMP/jdw:rs25/9 Enclosure 2146 086

Mr. Thomas Ippolito June 21,1979 Page Four STATE OF NEBRASKA)

)ss PLATTE COUNTY )

Jay M. Pilant, being first duly sworn, deposes and says that he is an authorized representative of the Nebraska Public Power District, a public corporation and political subdivision of the State of Nebraska; that he is duly authorized to execute this request on behalf of Nebraska Public Power District; and that the statements in said application are true to the best of his knowledge and belief.

A ~

a 'MT. Pilcnt Subscribed in my presence and sworn to before me thisf/_Mday of June 1979.

NOTARY PUBLIC /

My Commission expires / /fh .

ummsum.suew m MARLYN R. HOHNDOFF Ify Cene. Esp,0st.14.1s00 2146 087