ML20085E936
| ML20085E936 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 10/09/1991 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20085E924 | List: |
| References | |
| NUDOCS 9110210280 | |
| Download: ML20085E936 (3) | |
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o UNITED STATES
~'g NUCLEAR REGULATORY COMMISSION S_
WASHINoToN; D. C. 20656 p8-t
- %,.....,,A SAFETY' EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 17810 FACILITY OPERATING LICENSE NO. OPR-49 IOWA ELECTRIC LIGHT AND POWER COMPANY
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CENTRAL IOWA POWER COOPERATIVE CORN BELT POWER COOPERATIVE OUANE' ARNOLD ENERGY CENTER l
DOCKET NO. 50-331 1.0- INTRODUCTION By letter _ dated February 13,1990,. lowa Electric Light and Power Company-requested changes to the Duane Arnold Technical Specifications (TS) which consist _o_f: adding new-paragraphs 3.14.E and 4.14.E BASES and adding-this:
new information to Tables 3.14-1 and 4.14-1.
The changes concern the limit.
for the quantity of radioactive-material contained in low-level-liquid-
-radwaste tanks.
The proposed changes would allow each radwaste tank to 4
contain up.to 50 curies of radioactive material (from 10 curie limit in the
' currant TS) excluding tritium and dissolved 'or entrained noble sases.
The current 10 curie limit was. based on the. generic limit specified in the Standard' Radiological Effluent 15 for the outdoor liquid radwaste tanks.
2.0 ' EVALUATION.
To-meet anticipated radwaste storage needs : the licensee _- has constracted an onsite-low-level radwaste processing and storage facility.(LLRPSF).
The TLLRPSF=will'contain-3 liquid radwaste tanks:
(1) a 4,000 gallon capacity
>sampla tank (installed),-(2) a 7,000~ gallon capacity spent: resin holdup tank
- (installed),:and (3) a 70,000 gallon capacity radwaste surge tank (to be-_
installed).
The LLRPSF is not designed for the operating basis earthquake in_accordance-with the guidance provided in Section 5.0 of Regulatory Guide 1.143.
Accordingly, the staff treated the tanks in the-LLRPSF as outdoor tanks R
without surrounding liners or walls or area drain collection provisions, as-delineated in:.Section 15.7.3 of.the Standard Review Plan (SRP).
The_ sample-tank = receive's liquid radwaste from the. floor drain system in the LLRPSF processing area only. This area is not expected to contain
'significant levels of. radioactivity..The'_ surge tank will receive, among other liquid radwastes, backwash radwaste frota the reactor water cleanup 9110210280 911009 PDR -ADOCK 05000331 p
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. filter /demineralizers which will contain the highest level of radioactivity.
Therefc.e, the staff selected the future surge tank with 70,000 gallon capacity as the failed component in the LLRPSF for evaluation of the offsite consequences for postulated radioactive releases due to liquid-containing tank failure.
The staff assumed the anticipated iadionuclide inventory in the surge tank based on the expected failure fuel fraction that corresponds to 0.025 Ci/sec offgas release rate after a 30-minute delay consistent with the guidelines provided in SRP Section 15.7.3.
The staff further assumed that the surge tank in the LLRPSF will f ail instantaneously, releasing 56,000 gallons of its entire contents (80 percent of the tank capacity) to the soil, that the released liquids will percolate through the soil into the ground water, and that subsequent movement of the ground water will be directly toward the Cedar River.
The licensee has installed the retention basin and sluice gate to prevent any surface runoff of the failed tank contents.
In its evaluation, the staff accepted the licensee's estimated transit time of 1,000 days for the radioactive material to reach the Cedar River from the LLRPSF.
The transit time is cased on data obtained by the 1icensee from their well production studies performed at the Ouane Arnold site.
The data basis included a permeability of 0.01 cm/sec for the sand and clay soil mixture, an effective porosity of 15 percent, a flow gradient of 5 feet per 650 feet, and a distance of 1500 feet to the river from the LLRPSF.
No removal credit for dilution, dispersion, filtration, or ion-exchange of radionuclides was given during intrusion into ground water and ground water transport to the river.
The licensee calculated a dilution factor of 225 in the river using the guidance provided in NUREG-0868, "A Collection of Mathematical Models for Dispersion in Surface Water and Groundwater," dated June 1982.
The site-specific parameters used to calculate the dilution factor are 15 miles downstream distance to the municipal water intske from the potential release point, 1.65 feet per second average river water velocity, 400 feet river width and 5 feet river depth.
Using the dilution factor of 225 and the radwaste transit time of 1,000 days, the staff calculated the expected radioactivity concentrations at the Cedar Rapids Municipal Intake in the event of an uncontrolled release of the surge tank contents, and found that the resulting concentrations at the intake will be well below the maximum permissible concentrations specified in 10 CFR Part 20, Appendix B, Column 2.
Thecontrolyngradionuclideisstrontium-90withthe expected concentration of 1.6 x 10 pCi/cc (5 nercent of the limit) at the intake.
Since an uncontrolled release of the surge tank contents will not result in violation of 10 CFR Part 20 limits, the staff finds the increase in the limit for radioactive materials in the low-level liquid radwaste tanks to be acceptable.
"Ex3:n.,
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Iowa State official was notified of the proposed issuance of the amendment.
The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
S This amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or changes in a surveillance requirement.
The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative 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 (56 FR 31438).
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 CONCLUSION
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 o
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 Centributor:
Jay Lee Date:
October 9, 1991 L
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