NG-96-1297, Application for Amend to License DPR-49,consisting of TS Change Request RTS-290,revising TS Table 3.6.B.2-1 to Raise Reactor Water Conductivity Limit to Support Implementation of Noble Metal Chemical Addition

Application for Amend to License DPR-49,consisting of TS Change Request RTS-290,revising TS Table 3.6.B.2-1 to Raise Reactor Water Conductivity Limit to Support Implementation of Noble Metal Chemical Addition

ML20115E027
Person / Time
Site:	Duane Arnold
Issue date:	07/05/1996
From:	Franz J IES UTILITIES INC., (FORMERLY IOWA ELECTRIC LIGHT
To:	Russell W NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20115E028	List: ML20115E030 NG-96-1297, Application for Amend to License DPR-49,consisting of TS Change Request RTS-290,revising TS Table 3.6.B.2-1 to Raise Reactor Water Conductivity Limit to Support Implementation of Noble Metal Chemical Addition
References
NG-96-1297, NUDOCS 9607160067
Download: ML20115E027 (7)

Text

_. -. ._-

IES Utilities Inc.

. 200 Forst Street S E.

PO. Box 351 l

' Cedar Rapids, IA 52406-0351 l Telephone 319 398 8162 Fax 319 398 8192 John F. Franz, Jr.

Vice President Nuclear I

July 5,1996 NG-96-1297 Mr. William T. Russell, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission j Attn: Document Control Desk Mail Station Pl-37 Washington, DC 20555-0001 l

Subject:

Duane Arnold Energy Center Docket No: 50-331  !

Op. License No: DPR-49 Request for Technical Specification Change RTS-290, Reactor Water Conductivity Limit Change for Noble Metal Chemical Addition

Reference:

NRC Letter to IES Utilities Inc.," Summary of May 6,1996 Meeting on ,

Noble Metals Chemical Addition", dated May 22,1996 I File: A-117, B-11c

Dear Mr. Russell:

In accordance with the Code of Federal Regulations, Title 10, Sections 50.59 and 50.90, IES Utilities Inc. hereby requests revision to the Technical Specifications (TS) for the Duane Arnold Energy Center (DAEC).

This proposed TS amendment will support the implementation of Noble Metal Chemical Addition (NMCA) at the DAEC as a method to enhance the effectiveness ofIlydrogen Water Chemistry (HWC) in mitigating Intergranular Stress Corrosion Cracking (IGSCC) in Boiling Water Reactor (BWR) vessel internal components. An overview of NMCA has been discussed between the NRC, IES and General Electric Nuclear Energy (see Reference).

\

~

9607160067 960705 }

PDR ADOCK 05000331 P PDR g47A /> (

An IES Industnes Company

Mr. William T. Russell

,. NG-96-1297 July 5,1996 Page 2 This proposed TS amendment will raise the reactor water conductivity limit in Table 3.6.B.2-1 for reactor operating modes in STARTUP and HOT SHUTDOWN from 2.0 micromhos per centimeter ( mhos/cm) to 10.0 pmhos/cm only during the application of NMCA. Additionally, Sections 4.6.B.2.c and 4.6.B.2.d will be modified to ensure chloride and acidly (pH) are monitored periodically during the NMCA. The application is anticipated to increase the conductivity above the current limii The reactor water conductivity will be restored to the limit specified in Section 3.6.B after the NMCA.

This TS change request solely evaluates the change of the reacte ... .c conductivity limit in support of the NMCA. A 10 CFR 50.59 Safety Evaluation addressing the implementation of NMCA is in progress separately. The preliminary evaluation has not identified any unreviewed safety questions or new equipment failures that could cause different types of operating transients or accidents. The final 10 CFR 50.59 Safety Evaluation will be completed prior to implementation of NMCA. A summary of the Safety Evaluation will be submitted in accordance with 10 CFR 50.59.

This proposed TS amendment has been reviewed by the DAEC Operations Committee and the Safety Committee. A copy of this submittal, along with the evaluation of No Significant Hazards Consideration, is being forwarded to our appointed state official pursuant to 10 CFR Section 50.91.

The NMCA will be performed with the plant in a Hot Shutdown condition during Refuel Outage (RFO) 14, currently scheduled to begin in October,1996. We therefore request approval of this proposed TS amendment effective September 30,1996, with implementation prior to plant shutdown for RFO 14.

Should you have any questions regarding this matter, please contact this office.

l l

Mr. William T. Russell NG-96-1297 July 5,1996 Page 3 This letter is true and accurate to the best of my knowledge and belief.

IES UTILITIES INC.

By k -t n

[ John F. Fra' Vice President, Nuclear z

State ofIowa (County) of Linn Signed and sworn to before me on this s day of OM ,1996, by bk N . Mr(Ln L .

dMrk/\ . hhhJ6n Notary Public iH and for the State ofIowa l ,! BEVERLY A.SANDERSON t l1. G . Il'l> I%k ll -l> I%

Commission Expires 1

Attachments: 1) Evaluation of Change Pursuant to 10 CFR Section 50.92

2) Proposed Change (RTS-290) to the Duane Arnold Energy Center Technical Specifications

3) Environmental Consideration

4) Safety Assessment JFF/IIT N \lowa\ Licensing \ng96\96-1297. doc cc: 11. Tran L. Liu G. Kelly (NRC-NRR)

II. Miller (Region III)

S. Brown (State ofIowa)

NRC Resident Office Docu

1 RTS-290 Attachment I to '

NG-96-1297 Page1 of4 EVALUATION OF CHANGE PURSUANT TO 10 CFR SECTION 50.92 I

Background:

Noble Metal Chemical Addition (NMCA) has been developed by General Electric Nuclear Energy (GENE) as a method to enhance the effectiveness ofIlydrogen Water Chemistry (IIWC) in mitigating Intergranular Stress Corrosion Cracking (IGSCC) in Boiling Water Reactor (BWR)

{

vessel internal components. Additionally, use of NMCA will allow lowering injection rates of l HWC which in turn reduces plant radiation exposure over the life of the plant. An overview of NMCA has been discussed between the NRC, IES Utilities Inc. and GENE during a meeting on May 6,1996.

The NMCA application will be performed with the Duane Arnold Energy Center (DAEC) in a llot Shutdown condition during Refuel Outage (RFO) 14 with fuel in the vesse!. The NMCA process involves injection of a platinum-rhodium solution into the reactor water at a very dilute i concentration of approximately 100 parts per billion (ppb) of platinum (Pt) and approximately 100 ppb of rhodium (Rh) for at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> at a reactor water temperature of approximately 250 degrees F. The residual ions from the chemical compounds are sodium (Na*), potassium (IC), hydroxide (OH'), and nitrate (NO'3). These residual ions have minor effects on IGSCC in reactor vessel internal components. Any potential risk ofincreased crack growth rate (CGR) due to the residual ions during the application period will be outweighed by the reduction of CGR during subsequent operation with the noble metals in place. GENE has determined that the addition of these ionic species during the NMCA will not cause the reactor water conductivity to j exceed 10.0 micrombos per centimeter ( mhos/cm). Normal Technical Specifications (TS) l limits will apply following the application of noble metals when the reactor is placed in a cold condition.

During the injection period, the noble metal chemistry compounds will decompose and deposit a very thin, discontinuous layer of the noble metal onto all wetted surfaces. These treated surfaces will then behave catalytically and promote the recombination of oxidants (oxygen and hydrogen peroxide) that arrive at the surface with hydrogen. This results in low corrosion potentials of components at a low hydrogen injection rate, llence, a noble metal treated surface will reduce the propensity for IGSCC.

The current reactor water chemistry limits in the TS for the DAEC are established to prevent damage to materials in the reactor vessel, primarily stainless steel and the zircaloy cladding.

Limits are placed on reactor water conductivity and chloride concentrations. Conductivity is limited because it provides an indication of abnormal conditions and the presence ofimpurities in the reactor water. Chloride limits are specified to prevent stress corrosion cracking of stainless steel. When the continuously indicated conductivity is in its proper normal range, acidity (pil),

RTS-290 Attachment I to NG-96-1297 Page 2 0f 4 chloride and other impurities which are not continuously monitored are also expected to be within their normal range. When conductivity becomes abnormal, chloride measurements are needed to determine whether or not chloride concentration is also out ofits normal range. A search of the DAEC Updated Final Safety Analysis Report (UFSAR) did not find any specific discussion related to the reactor water conductivity.

Thie TS change request solely evaluates the change of the reactor water conductivity limit in sup, ort of the NMCA. A 10 CFR 50.59 Safety Evaluation addressing the effects of NMCA is in progcess separately. The evaluation has not identified any unreviewed safety questions or new equipment failures that could cause different types of operating transients or accidents. The final 10 CFR 50.59 Safety Evaluation will be completed prior to the NMCA implementation. A summary of the Safety Evaluation will be submitted in accordance with 10 CFR 50.59.

IES Utilities Inc.. Docket No. 50-331.

Duane Arnold Energy Center. Linn County. Iowa Date of Amendment Reauest: Julv 5.1996 Descrintion of Amendment Reauest:

This proposed TS amendment will permit a higher value (10.0 mhos/cm) of the reactor water conductivity limit during the application period of NMCA when the reactor operating mode is in STARTUP or HOT SHUTDOWN. This will affect the DAEC TS, Table 3.6.B.2-1. Sections 4.6.B.2.c and 4.6.B.2.d will also be modified to ensure chloride and acidity (pH) are monitored on a frequency consistent with the elevated conductivity.

Basis for Pronosed No Significant llazards Consideration:

The Commission has provided standards (10 CFR Section 50.92(c)) for determining whether a significant hazards consideration exists. A proposed amendment to an operating license for a facility involves no significant hazards consideration if operation of the facility in accordance with the proposed amendment would not (1) 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 accident previously evaluated; or (3) involve a significant reduction in a margin of safety.

After reviewing this proposed TS amendment, we have concluded:

1) The proposed TS amendment will not significantly increase the probability or consequences of any previously evaluated accidents. l l

l RTS-290 Attachment I to NG-96-1297 j Page 3 of 4 l It is expected that during the NMCA application period, the reactor water conductivity will l

increase and exceed the conductivity limit of 2.0 mhos/cm specined in our current TS. Our current TS requires that whenever the reactor is in STARTUP or HOT SIIUTDOWN Mode, the conductivity shall not exceed 2.0 pmhos/cm for more than 48 continuous hours or be in HOT l SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

The expected increase in conductivity is due to the presence of noble metal chemistry in the reactor water and is appropriate during the application period. The deposited layer of noble metals is benencial for mitigating IGSCC in reactor vessel internal components. Other reactor i water chemistry parameters such as chloride and sulfate are not expected to change; pH is i expected to change but not out of the acceptable range. The reactor water chemistry parameters will be analyzed to ensure they are within the normal range, on a frequency consistent with the existing TS, Sections 4.6.B.2.c and 4.6.B.2.d when conductivity is elevated during the NMCA l application. I During and after the application, the Reactor Water Cleanup (RWCU) system will continue to operate to remove the excess ions from the reactor water and restore the reactor water conductivity to the limit specified in Section 3.6.B. Therefore, this proposed TS amendment will )

not signincantly increase the probability or consequences of any previously evaluated accidents.

l

2) The proposed TS amendment will not create the possibility of a new or different kind of accident. The proposed TS amendment will only permit a higher value of the reactor water conductivity limit during the application period of NMCA. The application is anticipated to increase the reactor water conductivity.

l l During and after the application, the RWCU system will continue to operate to remove the I

excess ions and restore the reactor water conductivity to the limit speciGed in Section 3.6.B. As l

is discussed above, the deposited layer of noble metals is beneficial for mitigating IGSCC in reactor vessel internal components. Therefore, this proposed TS amendment will not create the l possibility of a new or different kind of accident from any accident previously evaluated.

3) The proposed TS amendment will only permit a higher value of the reactor water conductivity limit during the application period of NMCA. The increase in conductivity is anticipated during the application and is appropriate. The deposited layer of noble metals is benencial for mitigating IGSCC in reactor vessel internal components. During and after the application, the RWCU system will continue to operate to remove the excess ions and restore the reactor water conductivity to the limit speciGed in Section 3.6.B. Therefore, no margin of safety is reduced as a result of the anticipated increase in conductivity due to the addition of the known noble metals.

l l

l

l l

RTS-290 Attachment I to l

, , NG-96-1297 Page 4 of 4 1

Based upon the above, we have determined that the proposed TS amendment will not involve a significant hazards consideration. I Local Public Document Room Location: Cedar Rapids Public Library,500 First Street SE, Cedar Rapids, Iowa 52401 )

Attorney for Licensee: Jack Newman, Al Gutterman; Morgan, Lewis & Bockius LLP, 1800 M Street NW, Washington, D.C. 20036-5869 l

l I

l i

l l

l

-