ML20112J686
| ML20112J686 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 05/31/1996 |
| From: | Borst F PUBLIC SERVICE CO. OF COLORADO |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| P-96044, NUDOCS 9606200395 | |
| Download: ML20112J686 (7) | |
Text
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O Public Service' P.O. Box 840 Dene,co m b a 16805 WCR 19 1/2; Platteville, Colorado 80651 June 17, 1996 Fort St. Vrain P-96044 U.
S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Docket No. 50-267
SUBJECT:
QUARTERLY SUEMITTAL OF THE 10 CFR 50.59 REPORT OF
- CRANGES, TESTS AND EXPERIMENTS FOR FORT ST.
YRAIM DECOMMISSIONING
REFERENCE:
NRC Letter dated November 23, 1992, Erickson to crawford (G-92244)
Gentlemen:
This letter transmits the quarterly 10 CFR 50.59 Report of Changes, Tests, and Experiments affecting Decommissioning of the Fort St.
Vrain (FSV)
Nuclear Station.
The attached report includes a description of each change, test and experiment as well as a summary of the safety evaluation. This report covers the period of February 16, 1996 through May 31, 1996.
This report is being submitted pursuant to condition (b) (2) of the
" Order Approving Decommissioning Plan and Authorizing l
Decommissioning of Facility", transmitted in the referenced letter, which states the following:
"The licensee shall submit, as specified in 10 CFR 50.4, 4
a report containing a brief description of any changes, tests and experiments, including a summary of the safety evaluation of each.
The report must be submitted quarterly."
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'P-96044' June'17, 1996 Page 2 If you have any questions concerning this report, please contact Mr. M. H. Holmes at (303) 620-1701.
Sincerely, h/u Y L h W Frederick J, Borst j
Decc miss Dning Program Director FJB/JRJ Attachment cc:
Mr. Michael F. Weber, Chief Decommissioning and Regulatory Issues Branch Regional Administrator, Region IV Mr. Robert M. Quillin, Director Radiation Control Division Colorado Department of Public Health and Environment
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June 1996 QUARTERLY 10 CFR 50.59 REPORT OF CHANGES, TESTS AND EXPERIMENTS FOR FSV DECOMMISSIONING
Background:
The following is a brief. discussion of 10 CFR 50.59 changes to the Fort St. Vrain (FSV) facility or procedures as described in the Decommissioning Plan (DP) and tests and experiments not described in the DP, in the time period from February 16, 1996 through May 31,-1996.
The. quarterly decommissioning reports are submitted pursuant to Paragraph (b) (2) of the FSV Decommissioning Order (issued in NRC j
letter dated November 23,-
- 1992, Erickson to Crawford), which I
states:
"The licensee shall submit, as specified in 10 CFR 50.4, a report containing a brief description of any changes, tests and experiments, including a summary of the safety evaluation of each.
The report must be submitted quarterly."
Chanaes to the FSV Facility or its Procedures as Described in the Decommissionina Plan There were no changes to the FSV facility as it is described in the DP during this reporting period. There were changes to the updated FSV Final Survey Plan (FSP), discussed in Section 4 of the DP.
The l
preface to the FSP contains criteria that permit implementation of 4
certain revisions to the FSP without prior NRC approval.
A safety evaluation was performed on recently proposed FSP revisions which determined these criteria were met, as discussed below.
j 1.
Changes to the FSP to Eliminate Requirements for Redundant Exposure Rate Measurements FSP Section 4.3.3,
" Measurement Frequency",
was revised to i
I eliminate redundant / duplicate exposure rate measurements in suspect affected areas.
Section 4.3.3 called for a minimum of 30 exposure rate measurement.s in each survey unit.
In Reference 1 the NRC approved a reduction in.the exposure rate measurement frequency in suspect affected areas from one measurement every 1 X 1 meter grid location to one i
measurement every four square meters.
This exposure rate l
measurement frequency is in accordance with the guidance of draft r
NUREG/CR-5849 (Reference 2),. which states:
"If gamma emitting radionuclides are among the potential contaminants, exposure rate measurements at 1 m 'from floor and lower wall surfaces are performed at a frequency of 1 systematic measurement per every 4 1
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m.". PSCo proposed this revision to the FSP in Reference 3.
2 The proposed change to the Final Survey Plan incorporates the exposure rate measurement frequency approved by the NRC, using the guidance of draft NUREG/CR-5849, requiring exposure rate measurements every 4 square meters in suspect affected areas, and eliminating the requirement for a minimum of 30 exposure rate measurements in a survey unit.
There is no guidance in draft NUREG/CR-5849 for a minimum number of exposure rate measurements in a given survey unit.
A survey unit consisting of 40 square meters could have 100%
coverage with as few as 10 exposure rate measurements, and taking an additional 20 measurements for the purpose of achieving a total of 30 would be superfluous.
Section 5.2.5 of the FSP identifies the equation for demonstrating that the mean of individual measurements in a survey unit is below the guideline value at the 95% confidence level.
The number of measurements in the survey unit is a parameter in this equation, and a sufficient number of measurements will need to be taken to demonstrate compliance with the 95% confidence level requirement.
This FSP change does not affect the statistical requirements of Section 5.2.5, and it is possible that exposure rate measurements could be required in addition to the one per 4 square meters in order to demonstrate compliance with the 95% confidence level requirement.
Another area of redundancy exists where the spatial distribution of required exposure rate measurements overlaps.
Where a survey unit specifically defined for the floor abuts a survey unit defined for the lower wall surfaces, there is overlapping of required exposure rate measurements and collection of exposure rate measurements within the two survey units effectively results in duplicate measurements.
The exposure rate measurements collected at the approved frequency one meter from the surface of the floor satisfy some (or all) of the exposure rate measurements required from the surfaces of the lower wall.
Rather than require two exposure rate measurements from the same point, one to satisfy the floor survey unit and a separate measurement to satisfy the wall survey unit, a single exposure rate measurement will be permitted to satisfy the requirements at the location point for both survey units.
The proposed change states: " Exposure rate measurements collected at a spacing of 1 measurement for each 4 square meters at a distance of 1 meter, from more than one surface, will satisfy the measurement requirements for each surface."
A similar redundant exposure rate measurement situation exists when equipment and systems are defined as one survey unit and the floors and walls of the room containing the equipment are in a separate survey unit.
The exposure rate measurements to be taken at one meter from the surface of equipment are often duplicated by exposure rate measurements required to be taken one meter from the 2
floors and walls of the room.
In nearly all instances, exposure
- r' ate measurements collected at-the approved frequency from the surface of the floor serve to satisfy the exposure rate measurement requirements for the equipment contained in the area. The proposed change would help eliminate duplication by permitting a single exposure rate measurement to be used where it applies to both the floor (and/or walls) of the room and the equipment surfaces.
The proposed change states: " Exposure rate measurements for equipment are not required when located in other survey units and the effective exposure rate measurement requirements are met."
It was determined that the FSP revisions described above do not constitute an unreviewed safety question and meet the following 1
additional criteria defined in the FSP that authorize PSCo to make changes to the FSP without prior NRC approval:
o The proposed revisions do not require changes to the Decommissioning Technical Specifications.
o The' proposed revisions do not reduce the required survey frequency for the classification of a survey unit.
o The proposed revisions do not increase the action levels for conducting investigation and followup surveys.
o The proposed revisions do not affect the statistical treatment of survey data in a manner which could reduce the confidence that the site meets the criteria for unrestricted use.
Based on the above, it was concluded that the FSP revisions to eliminate redundant / duplicate exposure rate measurements in suspect affected areas do not constitute an unreviewed safety question, and may be implemented without prior NRC approval in accordance with the FSP requirements.
2.
Changes to the FSV FSP to Eliminate Chain-of-custody Requirements for Final Survey Data The proposed change affects FSP Section 3.5.1.g,
" Chain of Custody", which states:
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" Procedures contained within the FSV Decommissioning Project Radiochemistry and Radiation Protection Manuals will establish responsibility for custody of samples and survey data between l
the point of measurement or collection until final results are obtained.
Survey data will be maintained in the possession of the individual, under direct surveillance or secured."
l The proposed change eliminates the chain of custody requirements for survey data, based on controls provided by the instrumentation 1
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and purvey documentation reviews used for collecting final survey
' data.
Requirements that apply to chain of custody of samples are j
not being changed.
Section 4.1.1 of Draf t NUREG/CR-5849, Reference 2, makes no mention of data custody, only the custody of samples under the heading
" Sample Chain-of-Custody".
Data generation, handling, evaluation, l
computations and reporting are discussed in this section under the heading " Data Management", but no recommendations or mention is j
J made concerning data chain of custody. This proposed change to the FSP is in accordance with the requirements for data management specified in Draft NUREG/CR-5849.
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Data from final survey measurements taken b the field is recorded l
using the Ludlum model 2350 Data Logger, where it is stored until j
downloaded to a computer.
If a 2350 is left unattended in the field, prior to downloading data, there is no function that allows editing of the stored data, it can only be reviewed.
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Operational functions of the Ludlum model 2350 Data Logger must be input through a communications device and these operations require multiple commands that are not possible without training on the operation and use of the 2350.
Parameters which govern the detector operations are checked prior to and directly after data i
collection.
Technicians trained on the 2350 possess the level of knowledge to determine if data has been compromised.
The detector 2
parameter settings cannot be changed without an access code.
During the review process, after data has been downloaded to a j
- computer, the responsible technician verifies the data to be accurate.
Data is also reviewed by one of the Field Operations coordinators before the survey is deemed acceptable.
In past characterization and final surveys at FSV over 1600 downloads of the data logger have been performed.
Based on interviews with those directly responsible, no instances of loss of measurement data have occurred of a nature that would have been prevented by maintaining custody of the data logger at all times j
from point of measurement until data downloading.
l It was determined that the FSP revisions described above do not j
constitute an unreviewed safety question and meet the following additional criteria defined in the FSP that authorize PSCo to make changes to the FSP without prior NRC approval:
i l
0 The proposed revisions do not require changes to the j
Decommissioning Technical Specifications.
o The proposed revisions do not reduce the required survey frequency for the classification of a survey unit.
0 T a proposed revisions do not increase the action levels for conoacting investigation and followup surveys.
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,o The proposed revisions do not affect the statistical treatment of survey data in a manner which could. reduce the confidence that the site meets the criteria for unrestricted use.
Based on the above, it was concluded that the FSP revisions to I
eliminate the chain-of-custody requirements for survey data do not constitute an unreviewed safety question, and may be implemented without prior NRC approval in accordance with the FSP requirements.
j Tests or Erneriments Not Described in the Decommissionina Plan No tests or experiments were conducted this reporting period that are not described in the DP.
References 1.
NRC letter, Pittiglio to Crawford, dated December 21, 1995 (G-95224) 2.
NUREG/CR-5849, " Manual for Conducting Radiological Surveys in Support of License Terminat. ion, Draft Report for Comment",
dated June 1992 3.
PSco letter, Fisher to Weber, dated October 12, 1995 (P-95077) l l
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