ML16340D195

Responds to Concerns Expressed in Re Discharge of Radiation Into Atmosphere & Radioactive Releases to Pacific Ocean

ML16340D195
Person / Time
Site:	Diablo Canyon
Issue date:	02/18/1983
From:	Harold Denton Office of Nuclear Reactor Regulation
To:	Marilyn Evans CALIFORNIA, STATE OF
Shared Package
ML16340D196	List: ML16340D195
References
NUDOCS 8303040137
Download: ML16340D195 (28)

Text

Docket tlos.:

50-275/50-323 hIr. Harit Evans, Chairman Central Coarct Region California Regional Water guality Control Board 1102 A Laurel Lane San Luis Obispo, California 93401

Dear Hr. Evans:

This is in response to your December 24, 1982 letter to Chairman Palladino which has been referred to me for reply.

In your letter, you raised four concerns.

Our response to each of these concerns is delineated below.

Concern This Board raised the question of the removal of gaseous radioactive isotopes by the rain and/or fog and the possibility of them entering the ocean or other waters in the vicinity.

Hr. Denton advised us that the solubility of the isotopes is available in the International Critical Tables.

This is not an answer to the original question.

Has the HRC carried out the calculations to determine the potential removal of the gaseous radioactive isotopes by thig mechanism?

What are the results of these calculations7 If it has not been considered, we would like to know why not.

Response

The staff includes a calculation of dry deposition in its assessment of doses from routine releases of radioactive mater ial.

Our evaluation of the dispersion of the radionuclides in and the disposition of radionuclides from the atmo-sphere was based on Regulatory Guide 1.111, "llethods for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light-Water-Cooled Reactors,"

Harch 1976. Regulatory Guide 1.109, "Calculation of Annual Average Doses to I<an from Routine Releases of Reactor Effluents for the Purposes of Implementing Appendix I," March 1976 was used to perform dose calculations.

A copy of each of these Regulatory Guides are enclosed for your information.

The deposition calculations in these guides include deposition during fog conditions.

The removal rates of certain gaseous radioactive isotopes by rain or other types of precipitation are significantly greater than removal rates by dry removal processes.

However, the fraction of the time that measurable precipitation occurs.is small.

The staff has conducted generic calculations which take into-.account-increased deposition rates during periods of rain.

These results show -this has an insignificant effect on -total deposition and would not alter the zonclasians.reached for -individual~l~much as Diablo Canyon where only dry deposition processes are assumed.

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'IIr. IsI. Evans Concern

Second, we still have several concerns regarding the release of radioactive material to the Pacific Ocean.

Hr. Denton's answer to our questions regarding the use of a dilution factor in calculating allowable radioactive releases is not very reassuring.

It seems to us that the technology must exist to keep all radioactive material out of the cooling water discharge system.

Closed cooling system plants such as Rancho Seco in California must use a different rad-treatment

system, since discharge to a water body is not available.

Is cost the only Justification for not requiring such a system at Diablo Canyon?

Please define "as low as reasonably achievable" in the context of comparing the Diablo Canyon rad waste treatment system to that used at Rancho Seco.

~Res ense As stated in our letter of July 21, 1982, all required measures have been taken to process contaminated liquid effluents within the Diablo Canyon facility to minimize the release of radioactive material to the Diablo Cove.

The operating license for Diablo Canyon Nuclear Power Station, Unit Wo 1, as will the license for Unit 2 when issued, contains technical specifications for operation, limiting the concentration and the quantity of radioactive material in liquid effluents from the site.

It should be understood that radioactive liquid concentrations can be reduced by dilution; however, the quantities (curies per unit time) are not substantially reduced by dilution.

The equipment in the radwaste treat-ment system reduces the quantity and in effect, also reduces the concentration in releases.

In Section 11.0 of the Safety Evaluation Report dated October 16, 1974 and Supplement No. 6 dated July 1977 (copies attached),

we evaluated the radwaste treatment system to be used at Diablo Canyon, and concluded that Unit

.I and 2 can meet the concentration limits of 10 CFR Part 20 and the quantity requirements of Appendix I to 10 CFR Part 50.

Present technology exists to remove all of the detectable radioactivity in liquid waste streams.

The radwaste treatment systems at Diablo Canyon and Rancho Seco use demineralizers and evaporators that are very highly efficient and are capable of removing at least 99.99% of the radioactive material.

As a natural character-istic of this equipment, as the purity of the water is increased the ability for the equipment to remove additional contamination decreases.

Therefore, at low concentrations which would be typical of the Diablo Canyon system, recirculating the waste or adding additional equipment will not improve the purity of the waste and further treatment would not be practical.

As stated

above, when the quantity requirements have been met, normally the concentration limits can be met without dilution, but since dilution is available at Diablo Canyon it can be used.

In our evaluation of radwaste treatment systems at nuclear power stations, such as Diablo Canyon or Rancho

Seco, we were required by the Comnission's regulations, OFFICE)

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Hr. H. Evans w 3 specifically 10 CFR Part 50, Section 50.34a, to determine if the installed equipment can meet the present state of technology discussed above, resulting in a radioactive liquid effluent that is "as low as is reasonably achievable."

This term. means as lour as is reasonably achievable taking into account the state of technology, and the economics of improvements in relation to benefits to the public health and safety and other societal and socioeconomical consider-

ations, and in relation to the utilization of atomic energy in the public interest.

We concluded that the installed liquid radwaste system at Diablo Canyon did contain the required technology, that additional equipment would not be practical, and that the releases would be "as low as is reasonably achievable."

In the case of Rancho Seco, a similar evaluation was presented in amendments to the Operating License DPR-54, Docket halo. 50-312, although the plant was licensed prior to the adoption of the "as low as is reasonably achievable" requirement.

Further comparison with the cost-benefits of the two systems would be nonproductive since they are designed to meet requirements for their respective sites.

Concern Our third concern which the Board feels was not adequately addressed in tlr. Denton's response is the potential for a major release of radioactive waste to the Pacific Ocean as the result of an accident or other uncontemplated release at Diablo Canyon.

The plants'mmediate proximity to the Pacific Ocean underscores the need for a comprehensive evaluation of existing and potential safety systems relating to liquid pathways.

We believe that such an evaluation is critical.

~Res onse In our July 21, 1982 response we stated that under current Commission regulations, Diablo Canyon falls into a category of plants that would not require review for consideration of probabilities and consequences of accidents more severe than design basis events, including liquid pathway studies.

Notwithstanding the con-clusion yoted above, the staff has assessed the consequences of severe accidents at other> coastal sites and at offshore locations (e.g. Liquid Pathway Generic Study NUREG-0440, copy enclosed).

Because the conditions at the Diablo Canyon site do nest,differ significantly from the primary assumptions used for the evaluat)on's at other coastal

sites, the staff would not expect the consequences of a se4er'e,accident through the liquid pathway to be significant at Diablo Canyon.

Concern In your(I,eview of ear thquake safety and design errors at this facility, we again request/

'hat you make sure that all structures and piping which may result in accide

. 81 or unauthorized discharge to the Pacific Ocean be thoroughly inspected and au )ted independently, and where necessary, brought up to standards which wi'll p event chemical or radioactive contamination of the ocean.

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- i As you may know, an extensive'ndependent seismic design'erification program has been underway for more than a year under the direction of Teledyne Engineer-ing Services.

In addition, approximately 1000 technical members of the Pacific Gas and Electric Company and Bechtel Corporation are assigned full time to the resolution of the seismic discrepancies found at the plant.

Moreover, we have contracted with our consultant, the Brookhaven National Laboratory to conduct independent analyses of certain structures and piping systems.

Let me assure you that every effort will be made to confirm that the Diablo Canyon plant has been constructed in accordance with the required seismic design criteria and that any deficiencies found will be remedied to assure that the criter ia are met.

The liquid radwaste system and associated chemical treatment are not required to be designed to Seismic Category I standards,

however, they have been designed to the appropriate qua'Iity group classifica-tion as delineated in Table 11.1 of Section 11.0 of our Safety Evaluation Report (SER) dated October 16, 1974.

The liquid radwaste

system, which is located within a Seismic Category I structure, has been previously evaluated in Section 11.0 of our SER for potential radioactive liquid spillage at the Diablo Canyon site and it was concluded that the release would not result in concentrations exceeding a small fraction of the limits of 10 CFR Part 20 Appendix B, Table II, Column 2.

In view of the above considerations, it is our view tl)at the design features to minimize and control the release of radioactive effluents to the environment have been appropriately addressed.

Sincerely, M@ud Rgiied by H, A. DeiitOii

Enclosure:

As stated Harold R. Denton, Director Office of Nuclear Reactor Regulation Distribution:

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Si cerely,

Enclosure:

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I trust that the above information is resp nsive to your concerns.

incerely,

Enclosure:

As stated Harold R. Denton, Director Office of Nuclear Reactor Regulation Distribution w encl.:

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Let me assure you that every effort will be made to confirm that th iablo Canyon plant has been constructed in accordance with the require seismic design criteria and that any deficiencies found will be remedied assure that the criteria are met.

I trust that the above information i responsive to your concerns.

Sincerely,

Enclosure:

As stated Harold R. Denton, Director Office of Nuclear Reactor Regulation Distribu 'on w o encl.:

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I trust that the above information i responsive to your concerns.

Sincerely,

Enclosure:

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UNITED S PATES NUCLEAR REGULATORY COMMISSION WASHlNGTON, D. C. 20555

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Docket Nos.:

50-275/50-323 ter. Marit Evans, Chairman

'Central Coast Region Cal.ifornia Regional Water Quality Control Board 1102 A Laurel Lane San Luis Obispo, California 93401

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Dear h1r.evans:

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.This js in response to your December 24, 1982 letter to Chairman Palladino which has been referred to 'me for reply.

In your letter, you raised four

'oncerns.

Our response to each of these concerns is delineated below.

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yO Concern This<Board raised the question of the removal of gaseous radioactive isotopes by the rain andlor 4'og and>the possibility of them entering the ocean o'r other waters.in the vicinity.

fear. Denton advised us that the solubility of the is'otopes is available in the'International Critical Tables.

This is not an

" answer to 'the original question. 'as the HRC carried out the calculations to fetermine the poten'tial

'removal of the gaseous radioactive isotopes by thiPmechanism2 What are the results of these calculations?

If it has not been considered, we would like to know why not.

gc The staff includes a calculation of dry deposition in its assessment of doses from rodtine releases of radioactive mat'erialY Our evaluati h of the dispersion of the radionuclides in and the dis osition of 'radiqnuclides from the atmo-sphere was based on Regulatory Guide 1.111, "Methods for Es Transport and Dispersion of Gaseous Effluents in)Routine Re Water-Cooled Reactors,"

March 1976.

Regulatory Guide 1.109 of Annual Average Doses to Man from Routine Releases of Rea for the Purposes of Iisplementing Appendix I," March 1976 was dos calculations.

A copy of each of these Regulatory Guide Tl~

imating Atmospheric eases from Light-

"Calculation tor Effluents used to perform are enclosed n

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W.'h'~P The removal rates of certain gaseous ra'dio'active isotopes by r'ain or other types of precipitation are significantly greater than removal rates by dry. removal processes.

However,'he fraction of the time that measurable p

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Mr. M. Evans Concern

Second, we still have several concerns regarding the release of radioactive material to the Pacific Ocean.

Mr. Denton's answer to our questions regarding the use of a dilution factor in calculating allowable radioactive releases is not very reassuring.

It seems to us that the technology must exist to keep all radioactive material out of the cooling water discharge system.'losed cooling system plants. such as Rancho Seco in California must use a different rad-

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system, since discharge to a water body is not available.

Is cost the only justification for not requiring such a system at Diablo Canyon?

Please define "as low as reasonably achievable" in the context of comparing the Diablo Canyon rad waste treatment system to that used at Rancho Seco.

~Res ense As stated in our letter of July 21, 1982, all required measures have been taken to process contaminated liquid effluents within the Diablo Canyon facility to minimize the release of radioactive material to the Diablo Cove.

The operating license for Diablo Canyon Nuclear Power Station, Unit No 1, as will the license for Unit 2 when issued, contains technical specifications for operation, limiting the concentration and the quantity of radioactive material in liquid effluents from the site. It should be understood that radioactive liquid concentrations can be reduced by dilution

however, the quantities (curies per unit time) are not substantially reduced by dilution.

The equipment in the radwaste treat-ment system reduces the quantity and in effect, also reduces the concentration in releases.

In Section 11.0 of the Safety Evaluation Report dated October 16, 1974 and.Supplement No.

6 dated July 1977 (copies attached),

we evaluated the radwaste treatment system to be used at Diablo Canyon, and. concluded that Unit and 2 can meet the concentration limits of 10 CFR Part 20 and the quantity requirements of Appendix I to 10 CFR Part 50.

Present technology exists to remove all of the detectable radioacti sty in liquid waste streams.

The radwaste treatment systems at Diablo Canyon a

8 Rancho Seco use demineralizers and evaporators that are very highly efficie and are capable of removing at least 99.99% of the radioactive material.

As a atural character-istic of this equipment, as the purity of the water is increa ed the ability for the equipment to remove additional contamination decreas s.

Therefore, at low concentration~,recirculating the waste or adding additio/al equipment will not improve the p3rity of the waste and further treatment would not be practical.

As stated above,~'when the quantity requirements have been met, normally the concentration l>imi

-an-be-met-withou~iLutim.,

but if dilution is available uk2)>4+

. it can be used.

Cost, therefore, is not a primary facto In our eva1*uation of radwaste treatment systems at nuclear power stations, such as Diablo Canyon or Rancho

Seco, we were required by the Commission's regulations,

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Mr. M. Evans specifically 10 CFR Part 50, Section 50.34a, to, determine if the installed equipment can meet the present state of technology discussed above, resulting in a radioactive liquid effluent that is "as low as is reasonably achievable."

This term means as low as is reasonably achievable taking into account the state of technology, and the economics of improvements in relation to benefits to the public health and safety and other societal and socioeconomical consider-

ations, and in relation to the utilization of atomic energy in the public interest.

We concluded that the installed liquid radwaste system at Diablo Canyon did contain the required technology, that additional equipment would not be practical, and that the releases would be "as low as is reasonably achievable."

In the case of Rancho Seco; a similar evaluation was presented in amendments to the Operating License DPR-54, Docket No. 50-312, although the plant was.licensed prior to the adoption of the "as low as is reasonably achievable" requirement.

Further comparison with the cost-benefits of the two systems would be nonproductive since they are designed to meet requirements for their respective sites.

Concern Our third concern which the Board feels was not adequately addressed in Hr. Denton's response is the potential for a major release of radioactive waste to the Pacific Ocean as the result of an accident or other uncontemplated release at Diablo Canyon.

The plants'mmediate proximity to the Pacific Ocean underscores the need for a comprehensive evaluation of existing and potential safety systems relating to liquid pathways.

We believe that such an evaluation is critical.

~Res ense In our July 21, 1982 response we stated that under current Commission regulations, Diablo Canyon falls into a category of plants that would not require review for consideration of probabilities and consequences of accidents more severe than design basis

events, including liquid pathway studies.

Notwithstanding the con-clusion noted above, the staff has assessed the consequences of severe accidents at other coastal sites and at offshore locations (e.g. Liquid Pathway Generic Study NUREG-0440, copy enclosed).

Because the conditions at the Diablo Canyon site do not differ significantly from the primary assumptions used for the evaluations at other coastal

sites, the staff would not expect the consequences of a severe accident through the liquid pathway to be significant at D'iablo Canyon.

Concern In your review of earthquake safety and design errors at this facility, we again request that you make sure that all structures and piping which may result in accidental or unauthorized discharge to the Pacific Ocean be thoroughly inspected I

and audited independently, and where necessary, brought up to standards which irill prevent chemical or radioactive contamination of the ocean.

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~Res ense As you may I;now, an extensive independent seismic design verification program has been underway for more than a year under the direction of Teledyne Engineer-ing Services.

In addition, approximately 1000 technical members of the Pacific Gas and Electric Company and Bechtel Corporation are assigned full time to the resolution of the seismic discrepancies found at the plant.

Moreover,,we have contracted with our consultant, the Brookhaven National Laboratory to conduct independent analyses of certain structures and piping systems.

Let me assure you that every effort will be made to confirm that the Diablo Canyon plant has been constructed in accordance with. the required seismic design criteria and that any deficiencies found will be remedied to assure that the criteria are met.

The liquid radwaste system and associated chemical treatment are not required to be designed to Seismic Category I standards,

however, they have been designed to the appropriate quality group classifica-tion as delineated in Table 11.1 of Section 11.0 of our Safety Evaluation Report (SER) dated October 16, 1974.

The liquid radwaste

system, which is located within a Seismic Category I structure, has been previously evaluated in Section 11.0 of our SER for potential radioactive liquid spillage at the Diablo Canyon site and it was concluded that the release would not result in concentrations exceeding a small fraction of the limits of 10 CFR Part 20 Appendix B, Table II, Column 2.

In view of the above considerations, it is our view that the design features to minimize and control the release of radioactive effluents to the environment have been appropriately addressed.

Sincerely,

Enclosures:

As stated Harold R. Denton, Director Office of Nuclear Reactor Regulation

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'alifornia Regional llater equality Control Board TO:

Chairman'al ladino ACTION CONTROL COMPL DEADLINE INTERIM REPLY FINAL REPLY FILE LOCATION DATES 1

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264 DATE OF DOCUMENT 12 24 82 PREPARE FOR SIGNATURE OF:0 CHAIRMAN 0 EXECUTIVE OIRECTOR OFSCRIPTION

@LETTER I-I MEMO + REPORT + OTHER Concerns re Diablo Canyon Nuclear Power Plant SPECIAL INSTRUCTIONS OR REMARKS Ref:

EDO 12023 ASSIGNED TO CATE INFORMATION ROUTING ento NRR 1

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Inspector & Auditor Pollc Evoluetlon Incoming:

From To:

Subject:

Harit Evans Bd 12 24/82 dischar e of of radiat)on )nto of an accident at Diablo Canyon 0

Prepare reply for signature of:

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as a result

,r LJ,..Commissioner rt 4

I Cl,POO, GC, CL, SOL, PA, SECY, IA, PE 0

Signature block omitted C3 Return original of incoming with response XQk For direct reply 0

For appropriate action C3 For information Suspense:

Jan 13 Raa'I Off. Kp F~

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eAih'oo,.

Remarks:

docket NRC FORM 62A

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For the Commission:

'Send three (3) copies of reply to Secy Correspondence and Records Branch ACTIGN SLIP

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