ML20235H597

Evaluation of Pilgrim Offsite Dose Calculation Manual Through Rev 2

ML20235H597
Person / Time
Site:	Pilgrim
Issue date:	01/30/1989
From:	Simpson F IDAHO NATIONAL ENGINEERING & ENVIRONMENTAL LABORATORY
To:	Meinke W Office of Nuclear Reactor Regulation
Shared Package
ML20235H588	List: ML20235H597
References
SIM-16-89, NUDOCS 8902230667
Download: ML20235H597 (12)

Text

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ENCLOSURE

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/NEL Idaho National Engineering Laboratory January 30, 1989 Mr. Wayne Meinke ,

Radiation Protection Branch Mail Stop 11D23 U. S. Nuclear Regulatory Commission Washington, D. C. 20555 I

REVISED LETTER REVIEW OF ODCM REV. 2 FOR THE PILGRIM NUCLEAR POWER STATION

- SIM-16-89

Dear Mr. Meinke:

Attached is a revised letter report for the Pilgrim Nuclear Power Station A E: ODCM review. This letter report contains minor modifications to the I

l original report.  !

Very trul yours, F. B. Simpson Nuclear Sciences lkw .

Enclosure As stated:

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l E:902230667 890213 PDR P

ADOCK 06000293 PDC

[EGzG , . P.O. sox 1836 Idaho Falls, ID BN15

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,, JAN 3 01989 ,

• I EVALUATION OF PILGRIM ODCM UPDATED THROUGH REVISION 2 - SIM-16-89 Boston Edison Company (BECo), the Licensee for Pilgrim Nuclear Power Station (PNPS), transmitted a complete ODCM for PNPS, updated through Revision 2, to the NRC with a letter from R..G. Bird (BEco) to Document Control Desk (NRC) dated August 31, 1988. (Page 8, containing Section 3.2.2 and part of Section 3.2.3 was missing from the copy of the ODCM received for review and the fiche of the NRC NUDOCS file. For the purpose of this review, it was assumed that the missing sections are essentially the same as in Revision 1.)

This revision was transmitted with the Licensee's Effluent and Waste Disposal Semiannual Report (for January 1,1988 through June 30, 1988), as required by the Pilgrim Technical Specifications. As part of preparing.

Revision 2, the Licensee did some reorganizing, making the ODCM into a clearer and better organized document. Also, explanations and data which were added made the document more complete. Many of the dose equations were rewritten with more complete subscript notation to prevent possible confusion in their application. New dose equations were added to account for usually negligible doses (e.g., from swimming and boating).

In addition to the Licensee-initiated changes to the ODCM, the Licensee t ,

addressed discrepancies identified in the Technical Evaluation Report g p ,N (TER) included as an attachment to the Safety Evaluation (SER) transmitted i

• to BECo by a letter from R. H. Wessman (NRC) to R. G. Bird (BEco) dated i October 28, 1987. The SER requested that the concerns identified in the attached TER be addressed by the Licensee. A copy of the recommendations from the SER and the Licensees responses are attached as a convenient reference.

The Licensee specifically addressed each of the 21 concerns noted in the TER, numbering the concerns sequentially for convenient reference. Most of the concerns were addressed as recommended in the TER. Responses that did not address the concerns in the manner recommended in the TER are discussed below, using the Licensee's reference numbers:

1. The Licensee will continue to use the highest dose rate to any organ or any age group for the purpose of ensuring that the 1500 mrem /yr dose rate limit of Technical Specification 3.8.D is not exceeded. A proposed Technical Specification will be submitted to provide clarification. This methodology is more conservative than required by Technical Specification 3.8.D.

3. The ODCM does not contain simplified flow diagrams illustrating the treatment paths and the components of the radioactive liquid, gaseous and solid waste management systems. This is not required by the Lic~ensee's RETS or NUREG-0133, but is a recommendation of

" General Contents of the Offsite Dose Calculation Manual " Radio-logical Assessment Cranch Technical Position, Revision 1 February 8,1979. .

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The' Licensee's calculation of' doses due to liquid effluentsois

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essentially unchanged from Revision 2. Section 4.2 of the ODCM indicates that the methodology follows the recommendations of

. Regulatory Guide 1 109, and " Boston Edison Company, Pilgrim.

Station Unit Appendix I Evaluation, April 1977" is referenced for the' values of the " mixing ratios." The~ recommendation in'the-

-review TER to use the flow of the condenser with no mixing ratio as the dilution-flow was based on the_ fact that the methodology of

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NUREG-0133 does not' include provisions-for using;a " mixing ratio" in the equation for the dose due.to consumption of aquatic foods.

Regulatory Guide 1.109 does allow its use, but the use of a mixing 7

ratio of 0.2 in the dose. calculation for aquatic foods taken from the discharge canal is questionable,.even on the basis of the original Regulatory Guide 1.109, dated March 1976.

The original version of Regulatory Guide 1.109 included Table A-1, which identified points (locations) at which liquid concentrations should be c.alculated for determining doses to 'an individual. For doses due to aquatic foods these points were the discharge canal

• (with no recommended value for the mixing ratio), plus other points which were defined by mixing ratios of 0.2 and 0.1.

Because of the lack of dilution water in ~ addition to the condenser.

discharge, the most reasonable interpretation of the contents of-

, this table is that a mixing ratio of 1.0 should be used for ,

t '..

. aquatic foods from the discharge canal, whereas the Licensee is T f- using 0.2 (See ODCM Table A-3). Regardless, Regulatory /

Guide 1.109, Revision 1 does not contain recommended values of mixing ratios, so the values from the original Regulatory Guide 1.109 should not be used without other justification, (e.g...by calculations using the methodology of Regulatory Guide 1.113.).-

12. The concern stated in the TER about methodology in Section 6.1 for establishing the liquid effluent radioactivity monitor setpoint:

was apparently not completely understood by the Licensee. As

- described in the ODCM, the setpoint corresponds exactly to the concentration in the radioactive liquid being released, plus background. With this setting the monitor should alarm at least intermittently during the release since the flow rate in the effluent line does not affect the concentration at which the monitor alarms. This fact implies that the calibration of the monitor (following PNPS Chemistry Procedure 7.3.38) results in a setpoint corresponding to a higher concentration than intended, or that the ODCM description differs from the methodology actually used to establish the setpoint. (Another possible explanation, applicable if the background at the. monitor location is significant and the background is measured without water in the discharge line, is that the presence of the liquid effluent being monitored shields the detector from the background. In this case the monitor would respond mainly to the radioactivity of the liquid effluent, resulting in the monitor being effectively set to alarm at a concentration slightly greater that that measured in the tank being discharged.) It is recommended that the Licensee (2)

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determine the cause of the apparent inconsistency between the -

' description in the ODCM and the actual practice:that permits n release'of radioactive liquids without causing spurious alarms.

15. . It' is recommended that.the first sentence-of-the last_ paragraph j of 'the response to Concern No.- 15, dealing with dose projections, l be- added to the' 0DCM,- although this is not specifically required.

by the technical specifications'.

20. The Licensee changed Figure 8-1 of.the ODCM slightly and added descriptive wording to Section 3.1.3 to better describe the liquid effluent pathway. Although the response is- not equivalent ^

=to that recommended in Concern No. 20, it meets the requirements:

of the Licensee's . technical specifications and NUREG-0133.

Only Concerns 3, 5.12, and'15 discussed above appear to. call for additional action, with Concerns 5 and 12 being by far the most significant. Adding the sentence as recommended for Concern 15 would improve.the ODCM. With the exceptions noted in the above discussions of Concerns 5 and 12 the~ Licensee's ODCM is considered to be, in general, within the guidelines of NUREG-0133 and the calculational methods

-described in Regulatory Guide 1.109, Revision 1.

- DuriNg this review, the following relatively minor items were noted, which ,.

would be worth addressing in a future Revision of the ODCM: T e

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1. A "A" is:omitted from the next-to-last paragraph in Section 4.2.2.

2. The word "on" in the last sentence 'of Section'4.4 should 'be "or."

3. The last sentence of the fourth paragraph of Section 4.4 should require that any other method used to estimate the direct radiation' component of the total dose should'be described in the report for which it is used to perform the dose estimate.

4. The third paragraph of Section 5.0 refers'to " conservative" values for mixing ratios, although the mixing ratio for the discharge ~does not appear to be conservative (See coments above concerning Response 5).

The Licensee may wish to revise the bioaccumulation factors for phosphorus in Table A-1. The current "best values" recommended by the NRC staff are 3000. for freshwater fish, 600 for freshwater invertebrates, 870 for saltwater fish, and 900 for saltwater invertebrates. Also, Section 4.4 of the ODCM would still be consistent with the recommendations of NUREG-0473 if the consideration of other nuclear fuel cycle facilities were required only within a 5 mile (8 km) radius instead of the 50 mile radius now required by the ODCM.

This review was performed by T. E. Young. .

1kw (3)

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Attachment A Pilerim Wuclear Power Station's Offsite Dese Cateu1ation Manual Boston Edison Comeany's Reseense to Nuclear Reculatory C a ission Concerns Identified in the NRC's Technical Evaluation Reeort (TAC #63012)

The attached is a listing of the concerns listed in Section 4.0 of Supplement 1 to Appendix 0 of NRC letter to Ralph G. Bird from Richard H. Nessman, dated October 26. 1987. TheassociatedchangestothePNPSODCNorjustification for not making changes are listed following each item.

NRC Concern No. 1 In Section 4.1, it is oncertain if the dose rate to the child's thyroid is identified as the maximum organ dose since the bases statement in Technical Specification 3.8.D identified the infant age group instead of the child age group.

Response No. 1 A proposed Technical Specification revision to Section 3.8.D will be submitted followinII startup that will ,

provide clarification. The clar fication will indicate

• ' the current practice of considering all age groups in ,

the organ dose calculation for iodines and particulate 7 f' with a half life greater than 8 days, and Tritium. The /

age group with the maximum estimated organ dose will continue to be used to ensure dose rates from gaseous effluents are within PNPS Technical Specifications.

NRC Concern No. 2 In Section 3.1.3, the location of the environmental release point for liquid radwaste batch releases from -

sources other than the 11guld radwaste treatment system should be identified in the ODCM.

Response No. 2 The following clarification has been added to Section 3.1.3: .

"All batch releases which are not processed through the liquid radwaste treatment system are also discharged through the outlet to the circulating water discharge canal. These untreated liquid effluent releases also e.nter the Cape Cod Bay at the outfal.1 of .the discharge canal."

NRC Concern No. 3 Figures 3.1, 3.2, and 3.3 contain diagrams showing the radiation monitoring systems. These radiation monitoring system diagrams are illegible and should be replaced.

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.. Attachment A (continued)

Response No. 3 Figures for the radiation monitoring systems are n' ot required by NUREG-0133 or " General Contents of the i Offsite Dose Calculation Manual," Revision 1, issued by a tranch Technical Position from the Radiological Assessment Branch dated February 8, 197g. S'nce the information on the radiation monitoring systems recommended by the Branch Technical Position is contained in the text of ODCM Section 3.2. Figures 3.1, 3.2, and 3.3 have been deleted. The location of these drawings have been listed in the text of.0DCM Section 3.2 (i.e., Section 7.12 of the PNPS Updated FSAR).

NRC Concern No. 4 In Section 4.A. the option for determining the quantity-Cws in the concentration equation by " estimates based on '

pr!or experience" is not consistent with 11guld sampling Table 4.8-1 of the technical specifications.

Response No. 4 Section 4.A has been revised and renumbered as 4.1. The -

definition of Cwi has been changed to be consistent with liquid effluent sampling described in PNPS' Technical Specifications as follows:

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k f 'Cv1. Concentration of nuclide 1 in the 11guld waste  ;

discharge volume prior to any dilution as determined by current isotopic analysis for gama emitting nuclides and most recent results from pure beta and alpha emitters. (mC1/cc)."

NRC Concern No. 5 In the equations of Sections 4.5 and 4.C. the dilution flow is represented by *F" and *%* and should be replaced with the average condensir cooling flow for the period to change the di'ution flow to the average flow of the discharge canal during the reporting per' od.

Response No. 5 The use of a mixing ratto value was malatained to allow for additional dilution in seawater at a given location of interest. The value has been designated *N1 ' and is defined as follows:

'Mi is the string ratto (reciprocal of dilution factor) at location 1 of exposure or harvest of aquatic food, from Table A-3 (dimensionless);*

In addition, the dilution flow (F) has been replaced with the volumetric flow rate in liters /yr (V). The definition of V specifies suminl1 both the 11guld L

effluent and condenser cooling /d lution water volumes.

The revised units (liter /yr) resulted in thanging the conversion constant to be dimensionally consistent. The  !

change does not reduce the accuracy of the equation.

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4 m j Attachment A (continued) '

NRC Concern No. 6 In Sections 4.D through 4.L. it is not clear from the equations that simultaneous dose rate contributions from the main stack and the' reactor building vent are 1nciuded.

Nesponse No. 6 The equations in Sections 4.0 through 4.L have been t revised and now correspond to the equations in Sections 4.3.1 and 4.3.2. - The following clarification of existing practices for summation of the two dose rate contributions has been added to Section 4.3:

" Summation of the doses from the equations below should be performed for all significant pathways and all release points from which significant radioactive effluent releases have occurred (i.e. Main Stack and Reactor Sullding Exhaust Vent)." .

I NRC Concern No. 7 In Sections 4.H through 4.L the titles identify -

• Haiogens, particulate and others" instead of I

• 1odine-131, todine-133, tritium, and all radionuclides in particulate form with half Ilves greater than 8 days"..[t b Response No. 7 '

The titles in Sections 4.H throu h 4.L have been revised and now fall under the title in kection 4.3.2 which 1s:

" Gaseous pathway Annual Dose Rates for Iodine 131 and 133, particulate with Nalf-Life Greater than 8 days, and Tritium".

NRC Concern No. 8 In Section 4.H. the equation for the annual dose rate ~

from ground deposition contains an *1* in the denominator, whereas it should be A1 Response No. 8 The equation in Section 4.H has been revised and now corresponds to equation 4.3.2.1. The etssing lambda symbol has been included into the equation for the l annual dose rate from ground deposition.

NRC Concern No. g In Sec 7 the constants 1.2x10 ,

2.2x10jlons

. 5.5x104.3 7, andthrough 1.1x10 4.L.8 are not defined.

Reiponse No. g The constants in the equations in Sections 4.3 through  !

4.L have been changed. These constants are defined 'n Section 4.3.3 as follows:

• 1.19E7 - is equal to 1.00E12 pC1/C1 divided by 3.15E7 j sec/yr and multiplied by 1.00E3 g/kg and by 0.5 g H-3 in plant water per g H-3 in atmospheric water from  ;

Reference 23 (dimensionless) and by 0.75 g water per g plant (dimensionless) as calculated in Reference 1 equation C-9, (pCl-yr-g/Cl-sec-kg);

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Attachment A (continued) 2.18E7 - is equal to 1.00E12 pC1/Ci divided by 3.15E7 sec/yr and multiplied by 1.00E3 g/kg and by 0.11 0 Carbon /g plant pass from References 24 and 25 div ded by 0.16 9 Carbon /m3 of air as calculated in Reference 1 equation C-8, (pCi-yr-m3/C1-sec-kg);

5.71E7 - is the conversion factor to correct for activity units, time units, and elemental forms of radiciodines, equal to the particulate nuclide conversion factor 1.14E8 aultiplied by an elemental iodine fraction of 0.5 from Reference 26 (PCI-yr/Ci-hr);

1.14E8 - is the conversion factor to correct activit units and time units for particulate radionuclides, y equal to 1.00E12 pC1/C1 sultiplied by 1 yr/8760 hr, (pti-yr/Ci-hr);"

NRC Concern No.10 In Section 4.L. the definition for the quantity Og

,, e should not' include the word " annual" since.the air dose[

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' or air dose rate is already being considered "for the period".-

Response No.10 The appears now definitioninofSection Os in Section 4.3.3 as 4.L has been revised and follows:

"Os - is the annual release rate of nuclide 1 in gaseous effluents, (C1/yr);"

l The use of the word " annual" has been maintained for ,

i clarity and dimensional consistency. For purposes of performing calculations, all input and output values j (activity, use factors, dose rates) are normalized to a 1 year period to prevent inconsistencies in time factors. Thus, the air dose rate and the quantity Q1-definitions are consistent in that they are both expressed as an annual rate.

NRC Concern No.11 In Section 4.L. the time unit " hours" has been omitted from the definition for te. , ,

Response No.11 The definition of t. In Section 4.L has been revised and now appears in Section 4.3.3 as follows:

• te - is the time period that crops are exposed to radio-nuclide deposition during the growing season, from Table E-15 (hr);" l The time unit *(hr)" is now indicated in this definition.

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4 Attachment A (continued)

NRC Concern No. 12 In Section 6.1, the setpoint for the 11guld radwaste monitor is set to the level determined from the prerelease grab sample with no margin allowed. It is not clear if plant operation is consistent with the 00CM description since the monitor should be alarming continuously during a release, thus preventing the release.

Response No. 12 Technical Specification 3.8.8.1.a allows for the setpoint of the effluent monitor to be set to a more conservative level to allow for the discharge of radioactive liquid.

Pilgrim Station Procedure 7.9.2, " Liquid Radioactive Maste Discharge", directs the chealstry technician to

- recalculate the monitor trip setpoint ey utilizing form 1 CH - 11.A.2. This calculation uses detector efficiency and background, actual data of the discharge in -

question, and available dilution flow to determine an acceptable alarm setpoint that will allow the discharge and at the same time ensure that it will not exceed F. ~. 10CFR20 limits as prescribed in Section 3.g.A.1 of S.

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Technical Specifications. -

This methodology also ensures that the monitor does not inadvertently alarm continuously because of the conservative method used to determine the discharge flow rate of the tank.

WRC Concern No. 13 In Section 6.1.3, the documentation for estimating the monitor's efficiency ' based on prior release experience" is not referenced. -

f Reponse No. 13 The following sentence has been added to Section 6.1 l Item 3 to provide clarification and additional detail on efficiency determination:

"PNPS Chemistry Procedure 7.3.38 entitled.

' Determination of Conversion Factots for. Liquid PRM's',

de. scribes the method to determine the efficiency".

WRC Concern No. 14 'In Section 6 2, items 3) and 4) reference the equation of Section 4.0 and should reference the equations in Sections 4.F and 4.G Response No.14 Section 6.2 items 3) and 4) have been revised to reference the correct equations. These sections now reference Sections 4.3.1.3 and 4.3.1.4 for noble gas immersion total body dose and noble gas 1smersion skin dose, respectively. These sections correspond to the equations in Sections 4.F and 4.G.

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, ' Attachment A (continued)

NRC Concern No.15 A calculation should be included in the 00CM to project doses due to the release of radioactivity in liquid effivents to satisfy the requirement of Technical Specification 3.8.C.1 Response No.15 The equations used to project the monthly doses due to releases of radioactivity in 11guld effluents were given in Section 4.E and are now referenced in Section 4.2.

These equations as well as all other dose rate equations presented in the 00CM yield anual dose rate in erem/yr or eradlyr. The final result of any equation (s) must be )

scaled appropriately for the period of concern. Such j scaling is described at the introduction of Sections 4.2 and 4.3. For example, the following statement occurs in the introduction to Section 4.2:

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" Modification of final results is necessary for )'

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comparison to dose rate limits for periods different than one year. For comparison to monthly 11eits and quarterly limits, results would be scaled by 1/12 and 1/4, respectively. To determine the dose or dose comitment for a desired period, multiply the annual &-

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' dose rate by the fraction of the year for the dose t g: period desired." r For purposes of arciectino resulting dose estimates for the subsequent month, the release rates and concentrations are assumed to be equal to the previous sonth's release. Such a position was previously agreed upon in the RETS submittal and in associated meetings with Nuclear Regulatory Coenission staff.

NRC Concern No.16 A simplified diagram illustrating the solid waste treatment system is not included in the 00CN.'

Response No.16 A staplified diagram illustrating the solid waste treatment system is not included in the 00CM because Pligrim Nuclear Power Station does not have a solid vaste treatment system. ,

NRC Concern No.17 There is no separate section in the 00CM addressing the '

total dose limits of Technical Specification 7.5 with methodology for calculating the total dose from the liquid, gaseous, and direct radiation contributions.

tesponse No.17 A new section has been added to Section 4.0. Section 4.4, entitled, " Total Dose to a Nember of the Public",

which describes the methodology which was and is currently being utilized for calculating the total dose from the 11guld, gaseous, and direct radiation contributions. In addition, it addresses the conditions for when an assessment of the total dose must be performed.

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[ , .o l Attachment A (continued)

NRC Concern No. 18 The direction for Dunbury is NW of the plant site instead of *$SN-SH" as indicated in Table 7-3.

Response No. 18 The direction for the' Dunbury sampling location as well as all other sampling locations have been reviewed and .

t revised. The corrected distances and directions were i

! obtained by physical verification of exact positions of sampling location on maps, followed by ma computer and computer scaling techniques.p Thegeneration distances on and directions were obtained from the "to scale" digiti:ed maps shown in Figures 7-1 through 7-5.

1 NRC Concern ho. 19 Figures 7.1 through 7.4 are illegible and should be l replaced.

Response No.19 Figures 7.1 through 7.4 have been replaced. The new digitized maps showing the radiological environmental sampling and measurement locations appear as Figures 7-1 '

through 7-5.

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f NRC Concern No. 20 Figure 8-1 should be modified to show the one-inch and '

the two-inch discharge lines, the release pathway to the '

discharge canal, and the environmental release point for 11guid radwastes released without treatment.

Response No. 20 Figure 8-1 has been replaced with the corresponding figure from the PNPS Technical Specifications (Figure -

4.8-1).

it was not considered reasonable to modify the  ;

corresponding figure in PNPS Technical Specifications' to add this level of deta11. Instead a description of the one-inch low flow line and two inch high flow line was added to Section 3.1.3 as follows:

"The header provides controlled discharge through either a low flow discharge path or a high flow discharge path. The high flow path is normally used with a variable liqu' d radwaste effluent flow from 1-200 gpm.

The common discharge header extends from both the low

- and high flow-paths and is monitored for radiation prior to discharge".

The release pathway to the discharge canal and the environmental release point for liquid radvaste released without treatment were clarified in Section 3.1.3 as described in Response No. 2.

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. _o Attachment A (continued)

NRC Concern No. 21 Figure 8-2 in the 00CM shows the drywell- effuents being l re' ensed to the reactor building vent whereas Figure 4.8-2 in the Technict.1 Specifications shows these effluents being released to the main stack. The figures should be correct and consistent.

Response No. 21 Figure 8-2 has been replaced with the corresponding figure from the PNPS Technical Specifications (Figure 4.8-2), which is correct.

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