ML17300A842
| ML17300A842 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 05/14/1987 |
| From: | Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 161-00212-JGH-D, 161-212-JGH-D, TAC-65290, NUDOCS 8705210465 | |
| Download: ML17300A842 (14) | |
Text
REQULATO INFORMATION DISTRIBUTION STEN (RIDS)
ACCESSION NBR: 8705210465 DOC. DATE.: 87/05/14 NOTARIZED:
NO DOCKET 0 FACIL:STN-50-528 Palo Verde Nuclear Station>
Unit li Arizona Publi 05000528 AUTH. NAME AUTHOR AFFILIATION HAYNES> J. Q.
Arizona Nuclear Pouer Prospect (formerly Arizona Public Serv REC IP. NANE RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Forwards addi info re util 870510 proposed emergency Tech Spec change re secondary.
sos liquid waste.discharges to onsite evaporation ponder per 870512 telcon to/N-,- Licitra.
DISTRIBUTION CODE:
A001D COPIES RECEIVED: LTR ENCL 'IZE:
TITLE:
OR Submittal:
General Distributi,on NOTES: Standardized plant. N. Davis. NRR: 1Cg.
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Arizona Nuclear Power Project P.o. BOX 52034
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PHOENIX. ARIZONA85072-2034 May 14, 1987 161-00212-JGH/DAL U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C.
20555
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 1
Docket No.
STN 50-528 (License No. NPF-41)
Response
to NRC Information Request Regarding Proposed Emergency Technical Specification Change Secondary System Liquid Waste Discharges to Onsite Evaporation Pond File: 87-F-005-419.05 87-056-026
Reference:
(1)
Letter to E.
E.
Van Brunt, Jr.,
- ANPP, from E.
A. Licitra, NRC, dated May 12, 1987.
Subject:
Request for Additional Infor-mation on License Amendment Request for Palo Verde Onsite Ponds (TAC No. 65290)
(2)
Letter to USNRC (Document Control Desk) from E.
E.
Van Brunt, Jr.,
(ANPP) dated May 10, 1987 (161-00204)-EEVB/JRP).
Subject:
Proposed Emergency Technical Specification Change Secondary System Liquid Waste Discharges to Onsite Evaporation Pond
Dear Sirs:
In a telephone call with M. Licitra (NRC) on May 12,
- 1987, ANPP was requested to provide some additional information regarding the referenced letter.
This informa-tion request was forwarded to ANPP on May 13,
- 1987, by Reference 1.
Our response to this information requested is attached.
Very truly yours, J.
G. Haynes Vice President Nuclear Production JGH/DAL/ls Attachment CC:
0.
M.
E. E.
G.
W.
E. A.
R.
P.
J.
B.
A. C.
De Michele Van Brunt, Jr.
Knighton Licitra Zimmerman Martin Gehr (all w/a)
)g.gag 9e<<<<
Ooh 87052104b5 870514 PDR ADOCK 05000528 F
" PDR
I I
attachment to 161- 00212 ATTACHMENT 1'RC UESTION:
For the postulated event discussed in the bases for Specification 3/4.11.1.1, provide the results of the. analysis which demonstrates that the acceptance criteria for offsite exposure are met at any time during the life of the nuclear station.
This analysis should assume that the concentration Sb-124 in the discharged waste water is at the requested activity level until March 31, 1988.
ANPP RESPONSE As discussed in item E of the attachment to the referenced letter the addition of Antimony -124 to the evaporation pond over the period specified does not involve a significant reduction in the margin of safety, because the proposed change does not affect the design basis of the plant.
The existing limits for concentrations of radioactive material discharged from secondary system liquid waste to the onsite evaporation ponds will remain at 5x10-7 uCi/ml for principal gamma emitters.
Releases of Sb-124 may be allowed to exceed 5xlO-7 uCi/ml but will be limited to 10 CFR 20, Appendix B, Table II, Column 2
concentration for the period of this Technical Specification (which expires at 2400 hours0.0278 days <br />0.667 hours <br />0.00397 weeks <br />9.132e-4 months <br /> on March 31, 1988.)
This will allow PVNGS to maintain a dose to the public of less than 500 mrem per year from accumulated particulates in the evaporation ponds after the three units have been operating for 40 years.
Therefore, the contribution of Antimony to the post-40 year accident analysis dose would be negligible (less than 1 millirem per year/see Attachment 2) relative to the dose from the isotopes of the original analysis on which this Technical Specification is based.
This is consistent with the design basis of the facility.
A previous study of the evaporation pond requirements showed that the PVNGS ponds should not dry out during the 40 year plant life (Based on 65 inches per year evaporation rate-ref.
FSAR 2.4.8.2.2 and 2.4.8.3).
Therefore, wind deposition and resultant ground contamination does not occur.
Flows to the existing pond will continue until no more pond space is available (19 ft depth).
The ANPP recent forecast shows the current pond to be full by about March 28, 1988 (an additional pond is currently under construction).
If flow to this existing pond ceased at the time of pond fill, complete pond evaporation would conservatively take about 3.5 years (no credit for reduced evaporation with increasing pond TDS concentration).
The Sb-124 will have decayed away long before pond dry out, and no additional unrestricted area dose due to Sb-124 discharge would occur.
4 l
Attachment to 161- 00212 In addition the pond presently under construction is expected to be completed in the last quarter of 1987.
Assuming a September 1 completion, with plant discharges directed to the new pond only, the existing pond will have filled to a depth of about 12 ft by September 1.
Therefore, based upon the 65 inch per year evaporation rate, any remaining Sb-124 in the dried sludge would provide a negligible contribution to offsite dose.
Again no wind deposition would occur since the pond will not dry up under this conservative assumption.
At the same time the new pond depth will continue to rise, because the total unit input (including cooling tower blowdown) will exceed the evaporation rate.
For these reasons, it has been determined that the change does not involve a
significant reduction in the margin of safety.
(2)
Since the addition of Sb-124 to the onsite pond could represent a potential new release path for offsite exposure, discuss how Appendix I requirements are met for the proposed change to the Technical Specifications.
ANPP RESPONSE:
The response to Question 1 conservatively concluded that the ponds will not dry up during the period when Sb-124 is above the lower limit of detection (LLD).
The Sb-124 being discharged to the pond occurs as a (dissolved) solid.
This solid is left behind when evaporation takes place.
Since the ponds will not dry out before LLD is reached, as previously discussed, there is no new release path created.
No other release path will occur during the period when the Sb-124 is discharged to the pond and while Sb-124 is above the LLD.
Therefore, since no new release paths are available, there is no additional exposure or Appendix I impact created by this addition of Sb-124 to the pond.
PVNGS will remain well within the Appendix I criteria.
Other potential release paths such as a pond liner failure or a
failure are not considered in the bases to Technical Specification These potential release paths are,
- however, bounded by the analysis in FSAR Section 2.4.13.3.
pond dike 3/4.11.1.
described
I Attachment to 161-00212 ATTACHMENT 2 Dose from standing on Antimony-124 accumulated in evaporation pond for 1 year.
Assum tions Expected volumetric discharge flow rate of secondary wastes from Unit 1 to evap-oration pond is 57,640 gallon/day.
Sb-124 concentration in this flow is 2E-05 pCi/ml Case I Discharge duration 292 days Pond dryup time, 34 years or 1277 days Case II Discharge duration (5/24/87 to 9/1/87) 100 days Pond dryup time, 2.2 years or 803 days.
il Both cases Surface area is 255 acres 255 acres x 4046 meter
/acre 2
= 1.03 E+06 meter 2 Calculation Half life of Sb-124 is 60 days.
-1 Decay constant
= X =.693/60
= 1.16 E-02 day quantity accumulated at time of initial occupancy is:
(concentration)(flow rate)(buildup factor)(decay term)
[ ~
Attachment to 161-00212 Case I Quantity accumulated
=
(2E-05 pCi/ml)(5.764 E+04 gallon/day)(3.785 E+03 ml/gallon)(1B-06 pCi/
pCi)
(1/ ~ )(1
-(1.16E-02)(292))(
-(1.16E-02)(1277))
=(4.36&.09)(1-.03)(3.74E-07)(86.2) 1.36 El.05 pCi Divided by surface area:
1.362+05/1.03 E+06 = 1.3 E-01 pCi/meter 2 Times dose factor:
(1.3 E-Ol pCi/meter )(9.8 E-09 mrem/hour/pCi/meter
)
2 2
=1.3 E-09 mrem/hour For one year:
(1.3E-09 mrem/hour)(8,760 hour/year)
= 1.1E-05 mrem
~l
.'ttachment to 161-00212 Case XI Quantity accumulated
=
(2E-05)(5.764 E+04)(3.785 8+03)(1Et06)(1/1.16E-02)
(1
-(1.16 E-02)(100))( -(1.16F 02)(803))
=(4.36E'+09)(86.2)(1 e
)(e
= (3.76 E+11)(1-.31)(9.14E-05)
= 2.37 E+07 pCi Divided by surface area:
2.37EI-07/1.03E}06
= 23 pCi/meter 2 Time dose factor:
(23 pCi/meter )(9.8E-09 mrem/hour/pCi/meter 2
2
= 2.3 E-07 mrem/hour For one year:
(2.3E-07 mrem/hour)(8,760 hour/year)
= 2.0E-03 mrem
I t
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