ML20128G709
| ML20128G709 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 10/03/1996 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20128G673 | List: |
| References | |
| NUDOCS 9610090104 | |
| Download: ML20128G709 (3) | |
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UNITED STATES j
,j NUCLEAR REGULATORY COMMISSION 2
WASHINGTON, D.C. 3066NWC1
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4 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION i
RELATED TO AMENDMENT NO. 218 TO FACILITY OPERATING LICENSE NO. DPR-49 IES UTILITIES INC.
C.EHIR8L 10W8 fE18 LQQPIB811YE l
CORN BELT POWER COOPERATIVE l
DUANE ARNOLD ENERGY CENTER i-DOCKET NO. 50-331 4
4 1,. 0 INTRODUCTION By letter dated July 5, 1996, IES Utilities Inc. (the licensee) submitted a j
request for an amendment to the Technical Specifications (TS) for the Duane Arnold Energy Center (DAEC). The licensee requested an increase of the reactor water conductivity limit in Table 3.6.B.2-1 and several other changes i
in TS sections 4.6.B.2.c and 4.6.B.2.d, and the associated Bases to support the implementation of nobel metal chemical addition (NMCA). The licensee i
plans to perform NMCA when DAEC is in a Hot Shutdown condition during Refuel i
Outage 14 (RF0 14). The RF014 is scheduled to begin in October 1996.
The NMCA process was developed by General Electric Nuclear Energy (GENE) as a measure to enhance the effectiveness of hydrogen water chemistry (HWC) in mitigating the intergranular stress ccrrosion cracking (IGSCC) of reactor vessel internals in boiling water reactors (BWRs). The NMCA will deposit a very thin discontinuous layer of the noble metals on the component surfaces during the application period.
The treated surfaces will behave catalytically j
and promote oxidant-hydrogen recombination, which will allow the treated components to reach the low electrochemical corrosion potential (ECP) at low
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hydrogen injection rates. The low hydrogen injection rates will reduce the 4
plant radiation exposure over the life of the plant.
2.0 EVALUATION 2
The NRC staff has evaluated the following changes in the TS which were 1
proposed by the licensee to support the implementation of the NMCA:
l (1)
In Table 3.6.B.2-1, REACTOR COOLANT SYSTEM CHEMISTRY LIMITS (page j
3.6.6), the licensee proposed to add:
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(a) two asterisks to the conductivity limit for the STARTUP/ HOT
,i SHUTDOWN Modes and (b) a note of "** During Noble Metal Chemical Addition (NMCA),
10.0 pahos/cm is the limit.* to Table 3.6.B.2-1.
9610090104 961003 PDR ADOCK 05000331 P
i During the implementation of the MCA process, the conductivity is expected to increase and exceed the limit of 2.0 pahos/ca, because noble metal is beinq added to the reactor water.
The noble metal will form a thin discontinuous i
layer on the surface of the reactor internals which will enhance its resistance to IGSCC when mitigated with HWC. Noble metal in the coolant water i
is not expected to have any effect to the normal operation of reactor plant.
After completion of the NMCA process, the conductivity of the reactor water j
will return to the normal range allowed in the TS, because the excess noble i
metal is constantly being removed by the reactor water cleanup system. Since i
the increase of the conductivity limit is to support the implementation of the NMCA process and the excess noble metal will be removed after completion of i
the NMCA process, the NRC staff concludes that the proposed increase of the j
conductivity limit is acceptable.
j (ii)
In TS Sections 4.6.B.2.c and 4.6.B.2.d (page 3.6-4), the licensee i
proposed to add a monitoring frequency of at least once every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> for chlorides and acidity (pH) in reactor coolant during Noble Metal l
Chemical Addition (NMCA).
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The proposed additional monitoring of chlorides and acidity during the NMCA i
process is to ensure that the chlorides and acidity stay in the normal acceptable ranges when noble metal is being added to the reactor water.
j The NRC staff concludes that the proposed changes are acceptable.
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(iii) The licensee proposed to add the TS Bases for NMCA process l
(page 3.6-21) 1 i
The proposed addition in the Bases section dercribes the NMCA process and is editorial in nature. Therefore, it is acceptable.
i Based on the NRC staff's review, the staff concludes that the licensee's i
proposal to support the implementation of NMCA is acceptable. This is because i
the NMCA process will enhance the reactor internals in its resistance to IGSCC 1
and will also reduce the plant radiation exposure over the life of the plant i
when mitigated with the HWC. The increase in conductivity during the i
implementation of the MCA process involves no significant hazards and will i
not endanger public safety and health.
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3.0 STATE CONSULTATION
i In accordance with the Commission's regulations, the Iowa state official was l
notified of the proposed issuance of the amendment. The state official had no i
comments.
j 4.0 ENVIROMENTAL CONSIDERATIONS f
i This amendment changes a requirement with respect to installation or use of a i
facility component located within the restricted area as defined in 10 CFR Part 20 or changes a surveillance requirement. The staff has determined that j
the amendment involves no significant increase in the amounts, and no j
significant change in the types, of any effluent that may be released offsite, j
and that there is no significant increase in individual or cumulative 1
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. occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (61 FR 40020). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
5.0 CONCLUS(QH The staff has concluded, based on the considerations discussed above, that:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
W. Koo Date:
October 3, 1996