ML17306A213

Concludes That Actions Proposed by APS Re Revised Justification for Continued Operation for Postulated Rupture of High Pressure Seal Cooler Are Acceptable

ML17306A213
Person / Time
Site:	Palo Verde
Issue date:	10/09/1991
From:	Trammell C Office of Nuclear Reactor Regulation
To:	Conway W ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
References
TAC-79490, NUDOCS 9110210316
Download: ML17306A213 (8)

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Docket No. 50-528 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 October 9, 1991 Mr. William F.

Conway Executive Vice President Arizona Public Service Company Post Office Box 53999

Phoenix, Arizona 85072-3999

SUBJECT:

PALO VERDE NUCLEAR GENERATING STATION (PVNGS) UNIT NO. 1-REVISED JUSTIFICATION FOR CONTINUED OPERATION FOR POSTULATED RUPTURE OF HIGH PRESSURE SEAL COOLER (TAC NO. 79490)

We have completed our review of Arizona Public Service Company's (APS's or the licensee's) request to increase its administrative limit for equilibrium dose equivalent I-131 reactor coolant concentration from 0.2 to 0.4 microCi/gm for Palo Verde Unit No. 1.

This increase in allowable equilibrium iodine concentrations was requested by the licensee after reevaluations of the licensee's previous Justification for Continued Operation (JCO).

This reevaluation was performed to justify an increase in the administrative limit for equi librium dose equivalent I-131 to 0.4 microCi/gm until the next Palo Verde Unit 1 refueling outage, which is currently scheduled for February 1992.

By letter dated September 22, 1991, the licensee presented its justification for the requested change.

In this letter, APS noted that the JCO would be in effect only unti l the upcoming Unit 1 refueling outage in February 1992 and that the probabi lity of occurrence for this event was low, approximately 1.7 E-05 per reactor year.

In addition, the licensee noted that compensatory measures are in place to detect increased activity and take corrective actions and that exclusion area boundary doses are calculated to be less than 25% of 10CFR100 limits assuming an accident-generated iodine spike.

Until permanent design changes have been implemented, the licensee has implemented, as an additional precaution, routine sampling of the Nuclear Cooling Water (NC) system.

In the event that a leak from the NC system is detected from routine sampling or from continuous monitoring, a shutdown and cooldown within four hours would be performed.

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Mr. William F.

Conway This planned action provides added assurance against a flaw or unknown mechanism existing which could cause crack propagation in the cooler.

The leak detection capability will also ensure there is adequate time for operator action prior to the leak propagating to the point where the NC system would be overpressurized.

Finally, the licensee has indicated in its submittal that if the specific activity of the primary coolant exceeds 0.4 microCi/gm dose equivalent I-131 for more than 48 consecutive

hours, an orderly plant shutdown will be commenced and the unit will be in at least hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />; Based on our review, we find that the actions proposed by APS are acceptable to allow continued operation of Palo Verde Nuclear Generating Station, Unit I, with an allowable maximum reactor coolant system steady-state dose equivalent I-131 concentration of 0.4 microCi/gm.

This is applicable only unti 1 the next refueling outage of Palo Verde Unit I, on a one-time basis.

Sincerely, cc:

See next page Charles M. Trammell, Project Manager Project Directorate V

Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation

S

Mr. William F.

Conway Arizona Public Service Company CC:

Palo Verde Arthur C. Gehr, Esq.

Snell 5 Wilmer 3100 Valley Center Phoenix, Arizona 85073 James A. Beoletto, Esq.

Southern California Edison Company P. 0.

Box 800

Rosemead, California 91770 Senior Resident Inspector U.S. Nuclear Regulatory Commission HC-03 Box 293-NR Buckeye, Arizona 85326 Regional Administrator, Region V

U. S. Nuclear Regulatory Commission 1450 Maria Lane Suite 210 Walnut Creek, California 94596 Mr. Charles B. Brinkman, Manager Washington Nuclear Operations ABB Combustion Engineering Nuclear Power 12300 Twinbrook Parkway, Suite 330 Rockvi1 le, Maryland 20852 Mr. Charles Tedford, Director Arizona Radiation Regulatory Agency 4814 South 40 Street Phoenix, Arizona 85040 Chairman Maricopa County Board of Supervisors 111 South Third Avenue Phoenix, Arizona 85003 Jack R.

Newman, Esq.

Newman 5 Holtzinger, P.C.

1 il5 L Street, N.W., Suite 1000 Washington, D.C.

20036 Ignacio R. Troncoso Senior Vice President El Paso Electric Company Post Office Box 982 El Paso, Texas 79960 Roy P. Lessey, Jr., Esq.

Bradley W. Jones, Esq.

Akin, Gump, Strauss, Haver and Feld El Paso Electric Company 1333 New Hampshire Ave., Suite 400 Washington, D.C.

20036

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Nr. William F.

Conway This planned action provides added assurance against a flaw or unknown mechanism existing which could cause crack propagation in the cooler.

The leak detection capability will also ensure there is adequate time for operator action prior to the leak propagating to the point where the NC system would be overpressurized.

Finally, the licensee has indicated in its submittal that if the specific activity of the primary coolant exceeds 0.4 microCi/gm dose equivalent I-131 for more than 48 consecutive

hours, an orderly plant shutdown will be commenced and the unit will be in at least hot standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

Based on our review, we find that the actions proposed by APS are acceptable to allow continued operation of Palo Verde Nuclear Generating Station, Unit 1, with an allowable maximum reactor coolant system steady-state dose equivalent I-131 concentration of 0.4 microCi/gm.

This is applicable only until the next refueling outage of Palo Verde Unit 1, on a one-time basis.

Sincerely, ORIGINAL SIGNED BY cc:

See next page UTLON:

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Charles M. Trammell, Project Nanager Project Directorate V

Division of Reactor Projects III/IV/V Office of Nuclear Reactor Regulation FC 1

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