ML18058A549

Application for Amend to License DPR-20,changing TS to Delete Requirements Re Iodine Removal Sys Hydrazine Storage Tank Since Use of Hydrazine No Longer Considered in Current Rev of SRP

ML18058A549
Person / Time
Site:	Palisades
Issue date:	06/12/1992
From:	Slade G CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18058A551	List: ML18058A549 ML18058A554
References
NUDOCS 9206250216
Download: ML18058A549 (6)

Text

consumers Power GB Slade ..

General Manager

~-~ POWERINli MICHlliAN'S PROliRESS Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 June 12, 1992 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 -* LICENSE DPR PALISADES PLANT - TECHNICAL SPECIFICATIONS CHANGE REQUEST - DELETION OF HYDRAZINE REQUIREMENTS.

The enclosed Palisades Technical Specifications change request proposes deletion of the requirements which relate to the Iodine Removal System Hydrazine Storage Tank. The use of hydrazine is no longer considered in the current revision of the Standard Review Plan. In addition, continued use of the Hydrazine Tank would require construction of a costly secondary containment for the tank's contents.

Palisades has an agreement with the Michigan Department of Natural Resources to provide secondary containment structures for all tanks containing polluting materials such as oils or concentrated solutions of acids, alkalies, or salts.

The Hydrazine Tank comes under this agreement. Due to the location of the Hydrazine Tank, the construction of a secondary containment for its contents would cost in excess of $100,000. Since the use of Hydrazine is no longer necessary to assure iodine adequate removal from the containment atmosphere, these funds could be used more beneficially in other ways.

This change is necessary to allow elimination of the hydrazine which presents environmental and health hazards and operational difficulties.

Attachment 1 to the change request contains the proposed Technical Specifications page and Attachment 2 contains the affected existing Technical Specifications page marked to show the proposed change.

It is requested that these changes be made effective upon approval.

~~

Gerald B Slade General*Manager CC Administrator, Region III, USNRC Resident Inspector, Palisades Attachments

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1 CONSUMERS POWER COMPANY Docket 50-255 Request for Change to the Technical Specifications License DPR-20 For the reasons hereinafter set forth, it is requested that the Technical Specifications contained in the Facility Operating License DPR-20, Docket 50-255, issued to Consumers Power Company on February 21, 1991, for the Palisades Plant be changed as described below:

I. Changes It is proposed that Specification 3.19 be changed to delete the requirements relating to the Iodine Removal Hydrazine Tank, T-102. In addition, it is proposed that the remaining requirements of Specification 3.19 be rearranged in an updated format.

A. Item 3.19.1.a, specifying T-102 volume, concentration, and pressure requirements, should be deleted.

B. Item 3.19.1.c, specifying system operability requirements, should be revised to delete reference to T-102.

C. Table 4.2.2, items 12.b.1, and 12.b.2, specifying surveillance requirements for tank volume and concentration should be revised to delete reference to T-102.

D. Table 4.2.2, item 12.c, specifying surveillance requirements for automatic valves, should be deleted. The only automatic valves in the Iodine Removal System are those associated with T-102.

II. Discussion A. Background Hydrazine (N 2H2 ) was added to T-102 in support of Technical Specification change Amendment 31, Increase Plant Power Level From 2200 MWT to 2530 MWT, dated November 1, 1977. Hydrazine addition to the containment spray solution was required to increase the calculated rate of iodine removal from the containment atmosphere and thereby maintain the calculated offsite and control room doses, which would increase with the power level increase, within limits.

Additional restrictions on T-102 level (volume) and pressure (nitrogen cover gas) were added by Amendment 40, Enhancements to the Performance of the Iodine Removal System, dated April 12, 1978, to ensure that hydrazine was added to the Safety Injection Refueling Water Tank (SIRWT) discharge at the proper rate. The system was enhanced by addition of a nitrogen back-up to control air for the T-102 discharge valves to ensure hydrazine injection capability in the event plant instrument air was not available.

2 Post accident pH control is provided by sodium hydroxide solution addition to the recirculated solution in the containment sump. The requirements for sodium hydroxide addition are unaffected by these proposed changes. The Iodine Removal System is described in Section 6.4 of the FSAR.

B. Reasons for Changes Revised analysis methods have shown the addition of hydrazine to the containment spray water to be unnecessary. Elimination of the addition of hydrazine to the containment spray solution is desirable for the following reasons:

1) Hydrazine is both toxic and a carcinogen. Its presence in the iodine removal system creates a personnel hazard any time testing or maintenance is performed on this system, or during cleanup following any event leading to containment spray actuation.

2) The hydrazine addition equipment requires considerable maintenance effort; the required nitrogen cover gas pressure range is narrow and the hydrazine tank outlet valves utilize both control air and back up nitrogen for control.

3) Hydrazine is caustic and therefore its presence in the iodine removal system is a threat to the surrounding environment and a generator of hazardous waste.

4) Minor leakage through the hydrazine tank discharge valves enters the SIRWT with undesirable effects on that tank's chemistry.

C. Effects of Changes Since the requirement for addition of hydrazine to our containment spray solution was added to the Palisades Technical Specifications, the nuclear industry along with the NRC has changed their position on the effectiveness of hydrazine in increasing the iodine removal rate.

In fact, the current revision (Rev 2) of the Standard Review Plan (SRP), Section 6.5.2, states that "experiments with fresh sprays having no dissolved iodine were observed to be quite effective in the scrubbing of elemental iodine even at a pH as low as 5." Requirements for sodium hydroxide, used for post accident pH control, are unaffected by the proposed changes.

The current revision of the Combustion Engineering Standard Technical Specifications, NUREG 0212, does not require the use of hydrazine for iodine removal. As stated earlier, the purpose of adding hydrazine was to increase the containment spray solutions iodine removal rate.

However, as is seen in the table below, iodine removal rates calculated in accordance with the current revision of the SRP have significantly increased without the addition of hydrazine.

3 Calculated Hydrazine Removal Rates RELATIVE DESCRIPTION SPRAY SOLUTION IODINE REMOVAL RATE ( hr* 1 )

El ementa 1 Particulate Rate based on previous Borated Water 0.42 1.0 revisions of the SRP Rate based on previous Borated Water revisions of the SRP + >50 ppm 10 1.0 with Hydrazine Addition Hydrazine Rate based on current Borated Water 20 4.43 revision of the SRP*

Rate based on current Borated Water revision of the SRP* + >50 ppm 20 4.43 with Hydrazine Addition Hydrazine

• Standard Review Plan, Revision 2, Section 6.5.2.

The reason for the increased removal rate when using the current SRP revision is that spray droplet surface area is now used to calculate iodine removal rate instead of spray solution chemical composition.

As can be seen from the table, the removal rates calculated using.the current SRP revision are unaffected by the addition of hydrazine.

Therefore elimination of hydrazine from our spray solution will not reduce the iodine removal rate coefficients used to calculate offsite and control room doses.

D. CONCLUSION The function of containment atmosphere iodine removal will be accomplished as well by the borated spray solution alone as with the addition of hydrazine. The present revision of the SRP elemental iodine removal rate coefficients, with or without hydrazine addition, have doubled from the values used in Palisades accident analysis.

Therefore deletion of the hydrazine additive will not create any significant hazards or reduce any margin of safety.

4 III. Analysis of No Significant Hazards Consideration Consumers Power Company finds the activities associated with this proposed Technical Specifications change involve no significant hazards and accordingly, a no significant hazards determination per 10CFR50.92(c) is justified. The following ev~luation supports the finding that operation of the facility in accordance with the proposed change would not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated.

The hydrazine tank was installed solely for mitigation of the effects of a Loss of Coolant Accident (LOCA); it functions only following initiation of containment spray. Therefore, the probability of an accident will be unaffected by removal of the hydrazine tank requirements.

The function of the hydrazine tank, when it was installed, was to increase the removal of iodine from the post LOCA containment atmosphere. The presence of hydrazine in the containment spray solution has no effect on the iodine removal rate coefficients, as calculated in accordance with the current version of the Standard Review Plan.

Hydrazine, at Palisades, is not used for control of post accident pH in the containment sump. Sodium hydroxide is added to the post accident solution in the containment sump. Removal of the hydrazine tank will not affect the functioning of the sodium hydroxide tank.

Therefore, the consequences of an accident are not increased due to the removal of the Hydrazine Tank.

Therefore, operation of the facility in accordance with the proposed change to the Technical Specifications would not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Create the possibility of a new or different kind of accident from any previously evaluated.

The hydrazine addition tank was required only as an aid to removal of iodine from the post LOCA containment atmosphere. It has no function in preventing occurrence of any accident. Deletion of the requirements for the hydrazine tank, and subsequent removal of the tank and associated piping, will not introduce any new operation conditions. It will not affect the capacity, functioning, or settings of any other equipment.

Therefore, operation of the facility in accordance with the proposed change to the Technical Specifications would not create the possibility of a new or different kind of accident from any previously evaluated.

5

3. Involve a significant reduction in a margin of safety.

The sole function of the hydrazine addition tank was to enhance the removal of iodine from the post LOCA containment atmosphere. Current methods used for calculation of iodine removal rates predict no such enhancement from the use of hydrazine addition. The rate of iodine removal, calculated using the methodology of the current revision of the SRP, would be higher than the removal rate, calculated by older methodology, which was found to be acceptable in the Safety Evaluation Report for Amendment 31 to the Palisades operating license.

Therefore, the proposed change to the Technical Specifications would not involve a significant reduction in a margin of safety.

IV. Conclusion The Palisades Plant Review Committee has reviewed this Technical Specifications Change Request and has determined that the change involves no significant hazards consideration. This change has been reviewed by the Nuclear Performance Assessment Department. A copy of this Technical Specifications Change Request has been sent to the State of Michigan official designated to receive such Amendments to the Operating License.

CONSUMERS POWER COMPANY To the best of my knowledge, information and belief, the contents of this Technical Specifications Change Request are truthful and complete.

B~ (] ,._..___~~

David P Hoffman, Vice Nuclear Operations Sworn and subscribed to before me this ~ day of ~ < 1992.

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Notary Public

\)~Uj~C,o, Michigan My commission expires C./0./9~