ML023450244
| ML023450244 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 12/11/2002 |
| From: | Brockman K Division of Nuclear Materials Safety IV |
| To: | Quennoz S Portland General Electric Co |
| References | |
| +sispmjr200507, -RFPFR IR-02-002, IR-02-003 | |
| Download: ML023450244 (13) | |
See also: IR 05000344/2002002
Text
December 11, 2002
Stephen M. Quennoz, Vice President
Power Supply/Generation
Portland General Electric Company
Trojan Nuclear Plant
71760 Columbia River Highway
Rainier, Oregon 97048
SUBJECTS: (1) NRC UNRESOLVED ITEM NO. 50-344/0202-01
(2) CONFIRMATORY SURVEY OF CONTAINMENT
Dear Mr. Quennoz:
This refers to the subject Unresolved Item that was identified during the May 13-16, 2002,
inspection (NRC Inspection Report 50-344/2002-02) and the confirmatory survey that was
conducted during the August 5-15, 2002, inspection (NRC Inspection Report 50-344/2002-03).
During the May 2002 inspection, the NRC reviewed your staffs downward reclassification of
certain final survey units from the classification specified for these units in your approved
License Termination Plan (LTP). Although your license prohibits you from reducing scan
coverages for a given survey unit class, the License Termination Plan does not specifically
address downward reclassification of survey units; a condition which directly impacts scan
coverage for the reclassified survey unit. This issue was identified as an Unresolved Item. An
Unresolved Item is a matter about which more information is required to determine whether the
issue in question is an acceptable item, a deviation, a nonconformance, or a violation of NRC
requirements.
In reviewing the Unresolved Item, the NRC conducted a detailed review of your LTP, associated
implementing procedures, final survey results, NRCs confirmatory survey results as well as
interviews with personnel. In addition, the NRC met with Portland General Electric Company
(PGE) on July 10, 2002 to discuss the Unresolved Item and the issue of criteria for requiring
prior NRC approval for future final radiological survey activities. In response to the NRCs
concerns, your staff agreed to take several actions including providing NRC with advance
written notification of a proposed downward reclassification of a survey unit. Details of this
proposal were provided in PGEs letter to the NRC dated October 17, 2002. Consequently,
based on our further review of this matter, and consistent with your October 17, 2002 letter, we
consider Unresolved Item 50-344/0202-01 to be closed. A summary of our review of this item is
included in Enclosure 1 to this letter.
During the August 2002 inspection, the NRC conducted a confirmatory survey of the interior of
the containment structure. This survey was conducted by Oak Ridge Institute for Science and
Education, Environmental Survey and Site Assessment Program (ORISE/ESSAP), on behalf of
the NRC. As documented in the final ESSAP report, the confirmatory survey verified the
Portland General Electric Company -2-
radiological conditions of containment as reported by PGE and indicated that survey units were
classified appropriately as defined in NUREG-1575, Multi-Agency Radiation Survey and Site
Investigation Manual (MARSSIM), with one exception. NRC analysis of selected portions of the
confirmatory survey are provided in Enclosure 2 to this letter, and the final ESSAP report is
provided as Enclosure 3.
In the near future, PGE is expected to submit a final status survey report for the containment
structure interior to the NRC for review. The information provided in that report, as well as
information provided in the final ESSAP report and NRC inspections, will be used in the NRCs
determination of whether to approve the release of the containment structure for unrestricted
use. This decision will be provided to you under separate correspondence at a later date.
In accordance with 10 CFR 2.790 of the NRC's "Rules of Practice," a copy of this letter, its
enclosure, and your response (if any) will be made available electronically for public inspection
in the NRC Public Document Room or from the Publicly Available Records (PARS) component
of NRCs document system (ADAMS). ADAMS is accessible from the NRC Web site at
http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room).
If you have any questions concerning this inspection, please contact D. Blair Spitzberg, Ph.D.,
Chief, Fuel Cycle & Decommissioning Branch, at (817) 860-8191, or Mr. Robert J. Evans,
Senior Health Physicist, at (817) 860-8234.
Sincerely,
/RA MRShaffer Acting for/
Ken E. Brockman, Director
Division of Nuclear Materials Safety
Docket No.: 50-344
License No.: NPF-1
Enclosures:
1. Unresolved Item 50-344/0202-01
2. Confirmatory Survey of Containment
3. Confirmatory Survey of the Containment Building,
ORISE/ESSAP Report
cc w/Enclosures 1 & 2:
Lansing G. Dusek
Manager, Plant Support
Portland General Electric Company
Trojan Nuclear Plant
71760 Columbia River Highway
Rainier, Oregon 97048
Portland General Electric Company -3-
Chairman
Board of County Commissioners
Columbia County
St. Helens, Oregon 97501
David Stewart-Smith
Oregon Office of Energy
625 Marion Street NE
Salem, Oregon 97301
Lloyd K. Marbet
19142 S.E. Bakers Ferry Road
Boring, Oregon 97009
Jerry Wilson
Do It Yourself Committee
570 N.E. 53rd
Hillsboro, Oregon 97124
Eugene Roselie
Northwest Environment Advocates
133 S.W. 2nd Avenue
Portland, Oregon 97204
Douglas Nichols, Esq.
Vice President, General Counsel
and Secretary
Portland General Electric Company
121 SW Salmon Street
Portland, Oregon 97204
Michael B. Lackey
General Manager, Trojan
Portland General Electric Company
Trojan Nuclear Plant
71760 Columbia River Highway
Rainier, Oregon 97048
Portland General Electric Company -4-
bcc w/enclosure (via ADAMS distrib):
EWMerschoff
KEBrockman
DBSpitzberg
JLMinns, NRR/DLPM/PDIV-1
SWBrown, NMSS/DWM/DCB
SXSchneider, NMSS/DWM/DCB
JCDehmel, NMSS/DWM/DCB
CMCraig, NMSS/DWM/DCB
DTDiec, NRR/DSSA/SPLB
RJEvans
EMGarcia
FCDB File
MIS System
DOCUMENT NAME: S:DNMS\Fcdb\RJE\tn0202-URI.wpd Final: R:\_tn\2002\tn0202-URI.wpd
RIV:DNMS:FCDB NMSS:DWM:DCB NMSS:DWM C:FCDB D:DNMS
RJEvans JCDehmel CMCraig DBSpitzberg KEBrockman
/RA/ /RJEvans for via e /RJEvans for via e /RA/ /MRShaffer for/
12/03/02 12/09/02 12/09/02 12/10/02 12/10/02
OFFICIAL RECORD COPY T=Telephone E=E-mail F=Fax
ENCLOSURE 1
UNRESOLVED ITEM 50-344/0202-01
During the May 13-16, 2002, inspection (documented in Inspection Report 50-344/2002-02), the
NRC identified a number of concerns associated with the implementation of the final
radiological survey program in the decontaminated portions of the Reactor Containment
Building (Containment). The NRC determined that Portland General Electric (PGE) had
reclassified 18 survey units from MARSSIM1 Class 1 to Class 2, and designated the
reclassification of these survey units as initial, even though the Trojan Decommissioning Plan
and License Termination Plan (Trojan LTP) had already assigned an initial classification to
these areas at the time of its approval by the NRC. An Unresolved Item was identified in order
to determine whether the issues and approach used by PGE were acceptable practices, a
deviation, nonconformance, or violation. In addition, the NRC initiated a series of confirmatory
surveys in selected areas of the Containment and conducted an evaluation of the procedures
implementing the related elements of the final status survey program.
The NRC confirmatory surveys were conducted by Oak Ridge Institute for Science and
Education, Environmental Survey and Site Assessment Program (ORISE/ESSAP), under
contract with the NRC, during the August 5-15, 2002, inspection (NRC Inspection
Report 50-344/2002-03). The results of the confirmatory surveys indicated that the approved
Derived Concentration Guideline Level (DCGL) was exceeded in one area of the Containment
in which: (1) the survey unit classification had been down-classified because it was not
expected to contain areas exceeding the DCGL; and (2) the final surveys had failed to identify
the areas with elevated levels of residual radioactivity. The NRC was concerned because
PGEs final surveys had failed to identify areas exceeding the DCGL and that the survey units
did not meet the criteria for a change in classification. Details of the confirmatory survey are
included in the ORISE report2 which was issued in October 2002. A copy of the ORISE report
is attached as Enclosure 3.
During the October 7-10, 2002, inspection (NRC Inspection Report 50-344/2002-04), PGE
submitted to NRC inspectors additional information reflecting changes in final status survey
procedures that were prompted by the results of the earlier inspections of May 13-16 and
August 5-15, 2002. A review of the ORISE report along with information submitted by PGE,
indicated that the staff had enough information to address the Unresolved Item.
The NRC has reconsidered PGEs justification for reclassifying several survey units located in
Containment from a MARSSIM Class 1 to a Class 2 status in light of NRC confirmatory survey
results indicating that some portions of the areas located in the Containment were still above
the DCGL. The specific areas of concern to the NRC, as identified in prior inspection reports,
are addressed separately below.
1
Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM), NUREG-1575,
Revision 1, August 2000.
2
Confirmatory Survey of the Containment Building, Trojan Nuclear Plant, Rainier, Oregon,
ORISE/ESSAP, October 2002, performed under NRC contract.
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Regarding classification of survey units, PGE has maintained that the classification may be
assigned after remediation and prior to conducting final status surveys. The Trojan LTP allows
changes in survey unit classification using approved plant procedures prior to the start of final
status survey (LTP Section 4.2.4.4). The initial classification, listed in Table 4-4 of the LTP,
reflects the plants operational history and results obtained during characterization and
remediation. One procedure (RP 451, Final Survey Unit Design) addresses reclassification,
but the focus is on initial and upward reclassifications using professional judgment, along with
other information that may indicate that another classification might be more appropriate. The
process addressing upward reclassification was found to be acceptable and consistent with
MARSSIM. Regarding downward reclassification (i.e., from Class 1 to 2, Class 1 to 3, Class 2
to 3, or impacted to non-impacted), the LTP does not identify any data quality objectives to be
considered in the evaluation process.
The NRC maintains that any subsequent reclassification of plant areas should be identified as
revised since the LTP (Section 4.2.4.3 and Tables 4-2 and 4-4) indicates that the
classifications were the initial classifications. The classification of survey units is a critical
decision because it determines how much of any survey unit will be scanned, and this
determination carries more implications than sampling locations and number of samples taken
for analysis. It can be seen that if a Class 1 survey unit were reclassified as Class 2 with
insufficient radiological information and the scan coverage were reduced to less than
100 percent, there is the possibility that elevated levels of radioactivity could have gone
undetected and, consequently, a survey unit could be released with radioactivity still above the
cleanup criteria. In practice, radiological scanning provides the means to readily identify
locations where residual contamination levels exceed the DCGL. Accordingly, surface scan
coverage is one of the fundamental MARSSIM tenets and it should not be compromised.
MARSSIM specifically identifies criteria for assigning classifications. Sections 2.2, 2.5.2,
and 4.4 of MARSSIM indicate that areas characterized by contamination levels that are above
the DCGL prior to remediation; areas that were subjected to remediation or spills or leaks; or
areas where contamination levels are unknown must be classified as Class 1. The NMSS
Standard Review Plan (NUREG-1727, Appendix E, Section 1) reinforces this concept and
further states that areas that are on the borderline between classes should receive the more
restrictive classification. For these areas, PGE should have assigned the more restrictive
Class 1 designation, rather than Class 2, to the areas of the Containment either contaminated
at levels above the DCGL prior to remediation, or that were subjected to remediation or spills or
leaks.
In response to recent inspections and discussions with NRC staff, PGE has proposed3 an
alternative to provide the NRC with written notification prior to engaging in final surveys in
survey units that have been reclassified from Class 1 to Class 2, Class 1 to Class 3, or Class 2
to Class 3, as compared to Table 4-4 of the approved Trojan LTP. In its notification, PGE will
inform the NRC in no fewer than 14 calendar days prior to conducting any final status surveys
in affected survey units. The notification will include background information as to the
3
Letter from Mr. Stephen M. Quennoz, Vice President, Power Supply/Generation, to the U.S.
Nuclear Regulatory Commission, NRC Inspection Report No. 50-344/2002-02, Unresolved Item 50-344-
0202-01, Final Survey Unit Reclassification, dated Oct. 17, 2002, VPN-056-2002.
-3-
operational history and radiological information for the survey unit as the basis supporting the
change in classification. In support of that decision, PGE will take into account the fundamental
MARSSIM tenets on downward reclassification (Sections 2.2 and 5.5.3). The tenets include:
(1) a confirmation that no individual measurement would exceed the DCGL by using
measurements that provide a high degree of confidence; (2) a verification that contamination
profiles are absent of small areas of elevated activity; and (3) assigning a level of surface scan
coverage that is proportional to the potential of finding areas of elevated activity. PGE has
committed to revise the associated procedure (RP 451) in addressing the implementation of the
alternative approach. Under these conditions, the Staff finds the alternative approach
acceptable. In addition, the implementation of the revised procedure will be the subject of
future NRC inspections.
Recognizing that PGE is assembling similar information for areas of the Containment that were
not part of the confirmatory survey of August 5-15, 2002, the NRC staff will evaluate the related
results once it receives the final status survey reports from PGE. Any questions identified
during that review about sample results and removable surface activity levels will be handled as
requests for additional information (RAIs). Accordingly, Unresolved Item No. 50-344/0202-01 is
considered closed.
ENCLOSURE 2
CONFIRMATORY SURVEY OF CONTAINMENT
The NRC confirmatory surveys, conducted during August 5-15, 2002, focused on 25 out of 75
survey units located in the Containment. The 25 survey units were selected by the NRC based
on information provided by PGE, discussions held with PGEs staff, and walk-down of the
containment building. The NRC survey results indicated that, although most areas of the
Containment were below the applicable Derived Concentration Guideline Level (DCGL), some
measurements were found to be above the criterion. The survey results revealed that the
DCGL was exceeded in 5 areas, with 11 direct measurements above the limit. Table 1 provides
a list of survey units that were identified with small, discrete areas that exceeded the applicable
DCGL:
Table 1
Results of NRC Confirmatory Surveys Conducted in the Reactor Containment Building (a)
Survey Unit Section/Item Size (m2) Class Coverage (%)(b) Range of Results (c)
S01044E Sect. 17 & 18 591 2 50/60 0.2 - 2.3
S01044H Sect. 11 82 1 100 0.8 - 1.4
S01044J Sect. 13 & 14 81 1 22 1.2
S01044L Sect. 12 & Floor 110 1 100/90 0.5 - 1.30
S01195C Sect. 17 & 18 12 1 100/100 1.04
(a) The survey information is based on the final ORISE Report (Enclosure 3) and field data.
(b) Approximate percentage of area coverage by surface scan measurements.
(c) Rounded off results, expressed in multiples of the DCGL (22,000 disintegrations per minute per 100 square
centimeters, dpm/100 cm2). The results have not been corrected for the presence of naturally occurring radioactivity
in the materials and surfaces that were surveyed.
One Class 2 survey unit (S01044E) had a discrete area that exceeded the DCGL by a factor of
about 2.3. By definition, a Class 2 survey unit is not expected to have contamination exceeding
the DCGL. During the August 2002 inspection, the licensee confirmed the NRCs findings. The
initial actions taken by PGE included separating the survey unit into two units. The area with
the radioactivity above the DCGL was reclassified as a Class 1 survey unit, while the remainder
of the survey unit remained a Class 2 survey unit. This approach was determined to be
acceptable to the staff as a short term solution, pending the results of PGEs full investigation.
During the inspection of October 7-10, 2002, PGE submitted to NRC inspectors the results of
its evaluation4 and corrective actions. PGE confirmed via additional measurements that these
areas were indeed above the DCGL, a new Class 1 survey unit (S01044S) was carved out of
the Class 2 survey unit with the offending results, survey unit specifications for the prior survey
unit (S01044E) were revised to show this change, and a new survey was conducted in the new
4
PGE Memorandum from Mr. Larry Rocha to Ms. Gina Huey, NRC Inspection Follow-up Item
(IFI) 50-344/0203-01, FS-017-02, October 8, 2002.
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survey unit. The PGE survey results confirmed those of the NRC and reported yet other
elevated levels in the same vicinity. The results reported by PGE were found to be similar to
that of ORISE, ranging from 23,040 to 54,040 dpm/100 cm2. The sizes of the areas with
elevated radioactivity levels were reported to be very small, ranging from 0.01 to 0.8 square
meters (m2) and corresponding to about 0.01 to 0.80 percent of the total area of each survey
unit. In addition, smear samples taken in these area did not reveal removable surface
contamination levels that were above the limit of 2,200 beta dpm/100 cm2. The areas were
evaluated against the elevated measurements comparison test and found to pass the
associated criteria, using the Trojan LTP process and by applying As Low As Reasonably
Achievable (ALARA) concepts.
Among its findings, PGE stated that a more thorough evaluation of its operational and final
survey data might have concluded that an increase in scan coverage in the Class 2 survey unit
that failed the DCGL would have been warranted. Also, PGE noted that more detailed
instructions should have been given to the technicians who performed the final status surveys.
As a lessons-learned, PGE committed to revise its procedure (RP 453, Final Survey Data
Processing) to reduce the risk of missing areas with elevated activity levels. Collectively, the
NRC finds these corrective actions to be acceptable. The implementation of the revised
procedure will be the subject of future NRC inspections.
During the confirmatory survey, ORISE obtained five concrete samples that PGE had collected
and analyzed during the conduct of its own final surveys. Three steel samples (rebars) and one
steel sample taken from the steel liner, were obtained for analysis by high resolution gamma
spectrometry. In addition, 84 smears samples were taken on exposed surfaces. The results of
the concrete, steel, and smear samples were evaluated by the NRC:
- Concrete samples - The results for the five concrete samples were found to be under or
just above analytical detection limits. Radionuclide concentrations ranged from 0.27
to 0.84 picocuries per gram (pCi/g) for cobalt-57 (Co-57); from 0.24 to 0.80 pCi/g for
Co-60; from 0.02 to 0.20 pCi/g for cesium-137 (Cs-137); and from 0.61 to 1.86 pCi/g for
europium-152 (Eu-152). The results reported by PGE were noted to range from 0.188
to 0.772 pCi/g for Co-60, and from 0.69 to 1.88 pCi/g for Eu-152. PGE did not report
Co-57 and Cs-137 results for these samples since Co-60 and Eu-152 were deemed to
be the limiting radionuclides as defined in the derivation of the building-specific DCGL.
A comparison of the results indicates that PGE radionuclide concentrations are in
agreement with those of the NRC and below their respective DCGLs of 3.8 pCi/g for
Co-60, 11 pCi/g for Cs-137, and 8.7 pCi/g for Eu-152, as adjusted for surrogates, hard-
to-detect radionuclides, and the 10 percent rule in eliminating radionuclides (e.g., Co-57)
with minimal impacts on dose. Accordingly, the NRC finds PGEs concrete sample
results acceptable.
- Steel samples - The steel samples were analyzed by semi-quantitative screening using
high resolution gamma spectrometry. The analysis focused on the detection of Co-57,
Co-60, Cs-137, and Eu-152 using metal shavings collected from the bulk samples. All
results were found to be under their respective analytical detection limits, ranging from
0.37 to 1.3 pCi/g. The results reported by PGE range from -0.23 to 0.19 pCi/g for
Co-57, from -0.12 to 0.36 pCi/g for Co-60, from -0.15 to 0.04 pCi/g for Cs-137, and from
-0.13 to 0.03 pCi/g for Eu-152. A comparison of the results indicates that PGEs
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concentrations are in agreement with those of the NRC and below their respective
DCGLs of 3.8 pCi/g for Co-60, 11 pCi/g for Cs-137, and 8.7 pCi/g for Eu-152, as
adjusted for surrogates, hard-to-detect radionuclides, and the 10 percent rule in
eliminating radionuclides (e.g., Co-57) with minimal impacts on dose. Accordingly, the
NRC finds PGEs steel sample results acceptable.
- Removable surface contamination - A review of the smear/wipe data, indicates that the
results, taken at 84 locations, were either non-detectable or under the removable
surface contamination limit, i.e., #2,200 beta dpm/100 cm2 or #10 percent of the DCGL
adopted in the Trojan LTP. The results ranged from -4 to 120 dpm/100 cm2 for gross
beta radioactivity, determined using an automated gas-flow proportional counter.
Accordingly, the NRC finds that the approach used by PGE in demonstrating
compliance with removable surface contamination levels produces results that are in
agreement with its own results.