ML20128A658

Forwards Request for Addl Info Re Proposed Change 2 to TS to License DPR-22,modifying Gaseous Radwaste Sys & Adding Several Items Re Operation of Gaseous Radwaste Sys

ML20128A658
Person / Time
Site:	Monticello
Issue date:	06/03/1971
From:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
To:	Dienhart A NORTHERN STATES POWER CO.
References
NUDOCS 9212030417
Download: ML20128A658 (5)

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UNITED STATES ATOMIC ENERGY COMMISSION - w .m

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4 -Docket No. 50-263 y .

Northern States Power Company g ATTN: Mr. Arthur V. Dienhart w" Vice President klh Nicollet Mall Minneapolis, Minnesota 55401

, Gentlemen:

By letter dated April 1,1971, you submitted Proposed Change No. 2 to y the Technien1 Specifications of Provisional Operating License No. DPR-22 for the Monticello Nuclear Generating Plant E-5979. The purpose.of the m change is to modify the gaseous radwaste system and to add several items '

2 to the Technical Specifications relative to the operation of the gaseous g radwaste system.  ;

g As we discussed with your staff on May-ll,1971, we find that we need the additional infomation described in the enclosure before we can j complete our review of you.r application.

1 On the basis cf our preliminary evaluation we have concluded that the d proposed gasecus radwaste system will be an improvement over the existing k one. However, it may be that other systems being proposed for BWR's will be found to provide better performance than ;/our proposed system. (In your proposed change you make a eccparison only with a charcoal. delay system.) If such is the case, we may not be able to conclude that your system will achieve release levels that-are "as low as practicable".

The Commission has under consideration rule changes regarding effluent _

releases that may require additional or al'ernate modificutions to the Monticello gaseous radwaste system.

We will discuss the proposed changes -to the Technical Specifications with

$ you after we have finished our review of the proposed system.

Please contact us if you desire additional discussion or clarification of g '

the material ^ requested.

.A I Sincerely,

, Petex A. Morris, Director Division of Reactor Licensing 9212030417 710603

-PDR -ADOCK 05000263 fP, _PDR ,

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Northern States Power Company .,

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Enclosure:

Request for Additional Information >

cc: Gerald Charnoff, Esq.

Shaw, Pittman, Potts, Trowbridge and Madden l 910 17th Street, U. W.

! Washington, D. C. 20006 l

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i i REOUEST FOR ADDITIONAL INFORMATION RELATING TO

,. PROPOSED CHANCE NO. 2 TO MONTICELLO l

l TECHNICAL SPECIFICATIONS i

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1. From our meeting on your Change Request No. 2 on May ll, 1971, we understand that:

t a. All the equipment of the proposed waste gas system and the structure l in which it will be housed will be designed to withstand the Design I Basis Earthquake (seismic Class I), the Probable Maximum Flood (PMF) as defined by the Army Crops of Engineers, and the Design Basis Tornado (300 mph rotational and 60 mph translational winds with a 3 psi pressure drop in 3 sec);

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( b. You will provide us with data on the operation of the recombiner using BWR effluents (including trace amounts of iodine);

c. The equipment from the - ejector to the compressor will be designed i to 350 psig; i

l d. There will be a particulate filter upstream of the compressors;

e. You will explain how liquid discharges are handled from dilution stream and from the recombiner;

f. You will provide us with a list of changes made to the system since Change No. 2 was filed with the AEC;

g. You will revise the existing drawings in Change Request No. 2 to include all instrumentation; and

h. You will provide us with information explaining the operation of the unit under normal and abnormal conditions.

Please document the above listed items, and provide sufficient design details so that we can make an' independent evaluation of the adequacy of the design to meet these criteria. .

2. In Change Request No. 2 you state that "the shock wave of a hydrogen detonation could conceivably travel through the recombiner and underground holdup pipe up to the compressor suction." Designers of other similar systems have stated that there may be a possibility of a hydrogen explosion propagating throughout the system. It should also be noted that the flammable ,

concentration of hydrogen rises as the mixture is compressed. { '

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a. Explain why a hydrogen explosion th" ughm t tne system should not be considered, and

b. Explain your conclusion that the shock wave would not be propagated beyond the compressor suction.

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3. Deseribe the mechanical and/or electrical interlocks that will be installed j and explain the precautions that will be taken so that the wrong tank is not vented. Explain how you will reduce the potential for operator errors.

4. You have calculated the radiological consequences at the nearest site boundary of routine and accidental releases. Provide the meteorological L parameters and distences that were used to derive the atmospheric disper-sion factors for these calculations.

I 5. Evaluate the expected annual " fence post" doses at the most critical point l offsite due to releases from 1) containment purging, 2) steam turbine gland seal leakage, 3) HPCI turbine testing, 4) plant ventilation systems,

5) plant startup, 6) leakage from the proposed pressurized off-gas system,

7) liquid radioactive waste system vents, and 8) direct radiation shine f rom unenclosed tanks containing radioactive fluids. Present the bases for these doses including assumed scurce terms, rates and duration of re-l leases and type of release (ground level or elevated stack).

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6. Reevaluate the consequences of routine releases and accidental releases i

from the proposed off-gases system to include the dose contributions from

halogens and particulates. Present and justify all assumptions used to l make these evaluations. Include an analysis of accident doses that might be received by plant personnel and control room operators.

7. Clarify the statement on page 4 of the report entitled " Gaseous Radwaste System Modification Report" dated March 1971, that "The two remaining pro-cesses. . .were judged essentially identical with regard to environmental ef f ects , based on equal retention times. . ." .

8. Clarify what the 1% carryover refers to in Table 1 (Page 13) of the report mentioned in question 7.

9. Provide the design details of the proposed gas compressors that will provide capability for essentially cero leakage. What type of valves will be used and what is the expected leakage through the stem?

10. Provide design details of the air ejector off gas monitor and the stack monitors to show that representative samples of the noble gases, halogens and particulates can be obtained and that these monitors have sufficient sensitivity to detect plant releases at levels which will allow you to i

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l be confident of remaining within the new plant Technical Specifications limit (which will not allow an instantaneous release in excess of the i calculated maximum allowable annual average release of 0.27 Ci/see noble l gases and 2.4 uC1/sec of halogens and particulates with half lives greater than 8 days). '

31. k'here will the ventilation system f or the off-gas system building dis-charge? What type filtration and radiation monitoring system will be included in the system to limit, monitor, and record the potential releases from this building?

12. The storage room for the waste gas storage building will not be accessible when any of the tanks are pressurized. Discues the safety implications of this design feature. Include operational situations which would require remedial action to avert an accident or to avert a significant release of radioactivity and provisions (such as interlocks and alarms) that would prevent access of unauthorized personnel.

13. Provide a scaled plot plan indicating the location of the proposed facility relative to the stack, site property boundary, restricted area boundary, the exclusion radius and the nearest residence.

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