ML20206K616
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SAFETY EVALUATION REPORT PILGRIM NUCLEAR POWER STATION UNIT NO. 1 f
TECHNICAL SPECIFICATION CHANGE TO FACILITATE HYDR 0 GEN ADDITION TESTING P
By submittals dated February 1,1985 and February 15, 1985, the Boston Edison Company has proposed a Technical Specification change to permit a tcmporary increase in the Pilgrim Main Steam Line High Radiation scram and isolation setpoints to facilitate the testing of hydrogen addition water chemistry at their station. This proposed change is necessary to the test, since it is anticipated that Main Steam Line radiation levels may increase by factor of five over the routinely experienced dose rates during maximum 4
hydrogen addition rates.
i This evaluation was conducted to assure that the licensee has considered the radiological implications of the dose rate increase associated with N-16 equilibrium changes during hydrogen addition at i
BWR's, and to determine that the licensee has adequately considered radiation protection /ALARA measures for the course of the test in accordance with 10 CFR 20.l(c) and Regulatory Guide 8.8, "Information Relevant to Ensuring That Occupational Radiation Exposure At Nuclear Power Stations Will Be As Low As Is Reasonably Achievable."
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The licensee has indicated that normal radiation protection /ALARA practices and procedures for Pilgrim will be continued through the test. Additionally, main steam system dose rates will be monitored by surveys on a routine basis, particularly in accessible areas. An overall objective of the test is to determine general in-plant and site boundary dose rate increases as a result of hydrogen addition.
Additionally, specific locations where temporary shielding may be needed for long term implementation of hydrogen injection will be identified.
Fuel defects and failures will be monitored through the normal functions of the Main Steam Line Radiation Monitor (MSLRM), routine radiation surveys, daily primary coolant analysis, and the Steam Jet Air Ejector Off-Gas monitor. The trip function of the MSLRM for the design base rod drop accident will be preserved by performing test adjustments above 20% power.
J The staf f additionally discussed details of dose control measures and surveillance efforts planned for the test with licensee representatives. A similar test was proposed and conducted for the J
Dresden 2 facility following a staff review and approval of a similar Technical Specification change. The measures proposed for radiation protection /ALARA at Pilgrim are consistent with those utilized at Dresden during the successful tests at that unit, where no significant unanticipated, radiological problems occurred. The test conditions as identified by the vendor were also consistent with the observed conditions at Dresden 2.
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Based on the adequacy of the licensee's radiation protection /ALARA program, their utilization of special surveys to monitor dose rate increases on site and at the site boundary, the capability to monitor for fuel failures, the success of the initial effort at Dresden 2 and the consistency of that effort with anticipated results, and the licensee's discussion of specific radiation protection /ALARA measures to be utilized, we find that the licensee has the capability to assure worker radiological protection and keep doses as low as is reasonably achievable. Based on these capabilities and the licensee's planned actions, we recommend the Technical Specification change be approved as requested.
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2.3 METEOR 01.0GY hreeze occurrences; however, cince the data collected from this tower did not differ from that collected on the 220 foot 16 2.3.1 General meteorological tower, the obsenation, were discontinued.
The main fea tures of the wrather of castern The Pilgrim site mrtcorological data presented in this Mas ai husetts are sariety and changeabilit.s. The area lirs in report includes the first annual period from May,1968 a transition zone of westerly air currents which encompass through April,1969. The meteorological program at the q
the southward movement of polar air ma>>cs and northward site will continue through the summer of 1970.
mosement of tropical air masses. The area is frequently 4
1 situated in or near the tracks of low pressure systems during 2.3.3 Winds the Fall. Winter, and Spring seasons. As a tr> nit, the region Seasonal and annual wind roses for the 20 feet and has no dry season, with Summer precipitation noming in 220 feet tower level (100 and 300 feet MSI.) data at the the form of showers or thunderstorms. The coastline Pilgrim site are shown in Figures 2.31 through 2.310.The location of the site results in seasonal temperatures whic h predominate wind directional frequencies at the 220 feet
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are less extreme than inland locations due to on.shorr tower level (300 feet MSL) are in the sectors W.WNW, wimls in the Summer (scahreeze) and the presence of SSW.SW, WSW.WNW and WSW.WNW for Spring, Summer, i
relatively warm water in the Winter.
Fall and Winter resperthrly. Wimis ori ur in the SSW.WNW settors 53% of the time. The annual frequency of calm of Meteorological data are available fnim the on+ite l
weather station. Special sea breeze studies have bron 0.43%. The annual mean wind speed is 16 mph.
1 conducted to provide a better understanding of the local 2.3.4 Diffusiim Climatology
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wind regime.
The frnpient changes in wrather systems and the 2.3.2 Meteorological Field Program proxiniity of the ocean yield a thangeable wind velocity A meteorological tower has been in continnons op.r.
nyime which result in favorable atmospheric diffusion con ditions. The ocean's proximity results in a low ation since Mav.19fah The tower is 220 fert high and i, 1
located on grmmd at 80 feet rietation rrferred to mean 3ra I"'luency of inversion (stable) conditions with light winds.
p le el(MSh). The following ob.,enation., hase born made:
There are times, howeser, during the warm months of the j
year, that the waters off the Massachusetts coast are cold I.
Wind speed, direction and directional variability at compared to the land. When an rasterly wind develops, this 20 feet (100 feet MSL) and 220 fret (300 feet MSh) stable air will he advected over land resulting in somewhat j
using "Aerosaue" wind sensors.
less favorabic diffusion conditions.
2.
Temperatures at 5,110 and 220 feet (M,190 and 300 The coastline at the site generally follows a j
feet MSL) and temperature differences between northwest. southeast direction. Thus, the land breeze is 5 to 110 fret and 110 to 220 fret by means of intensified and the seahreeze is moderated by the regional resistance ty pe thermometers housed in aspirated solar wind pattern which is generally from the southwest radiation shirlds (offshore) in the summer. Ilowever, the site is situated so 3.
Occurrence or non. occurrence of precipitations by that any wimt from about 315 thnmgh north to 100* will means of a precipitation duration H nsor.
have an overwater trajertory upwimi of the site and an over in addition to the metroiological data, water land trajectory immediately downwind from the station.
t e m peratures obtained as part of the oceanographic Diffusion climatology has been analyzed from pnigram, described riscwhere, worr nord in the ora brerzr metrondogical data obtained at the Pilgrim site for the l
a nalpis. An infrarni radiometer survey of the hay was period May,1968 through April,1969. The most pertinent comlucted to assure that representathe water tempriatun s results are persented in the following tables and figures:
were ohtained.
i
- 1) Annual Stability Summary and Comparison of On April 2,1969, the lower anemometer on the tower Seasonal Inversion Frequenries, Tables 2.3.1 was raised from 20 feet to 70 feet (150 feri MSh) to obtain and,,. 3..,
more reprerrntative data during onshore llow regimes. Th"
- 2) Annual wind summaries, wind directional persistence data at the prnious Irvel was adversely affected by the and inversion persistance at 300 feet MSL, Tables arrody namie effect of the lluff along the brach to the cast.
2.3.3 through 2.3.10.
An a.blitional trmperature sensor and an "Arrovane"
- 3) Wind roses at 300 feet MSL by 16 compass points, wind,. ens..r was installed on June 20,1969, on a radio Figures 2.311 through 2.314.
tower at a 1.,rl 100 feet above grade (rInation of 370 feet
- 4) Wind directional variability and wind speed (o0E) by Msh). Gi tower is located on the south side of route 3A six wind speed ranges, Tables 2.3.1 la through 2.3.Ild.'
about do feet south-southwest of the reactor hiration.
These data give a direct measure of lateral diffusivity 16 I hi,in-ta'llation was intended to prmide additional data for and an indirect measure of vertical diffusivity, evaluatidn of psrudo fumigation conditions during sea Of particular interest at the Pilgrim site is the potential i
OO 2.3 1 Q\\
p PNPS behavior of a plume from an elevated relea e under the can occur during all s asms resulting from thunderstorms e
influen. e of an onehore wind (.-ca breeze) during gwriods in the late Spring and Summer, hurricanes during late when the water surface is appreciably colder than the land S u m mer and Fall and extratropical coastal cylones 3nrfare. The modification of a cohl, mer-water, stable (northeaster 3) during the Winter and Spring. Precipitation ainnam, into an unstable regime as it moses inland and is data for Plymouth, Ma-achusetts, is shown in Table 2.3.13.
heated can result in a pseudo-fumigation condition. This The monthly average and maximum snowfall, the phenomenon is discus-ed by Van der lioven in Reference 2.
nwximum 24. hour snow fall, and t!. average number of P>eudo fumigation behasior under sea breeze conditions days per month with a snowfall of 1.0 inch or more for was studied by a heries of smoke releases from tbe top of Ibton are shown in Table 2.3.14. Snowfall in the site the 220 foot tower (300 feet abmc mean sea level)during sirinity is generally less than ! bion.
the summer of 1969. The details of this sea breeze study A few times each Winter a weather situation favorable are reported in Appendix 1.
for ice glaze formation develops. The coastal location of the The radiological consniuences of the diffusion site reduces the likelihood of a glare. forming storm climatology are described in Appendis E.
compared to nearby inland locations. During the period of 2.3.5 Temperature record 1928 to 1936, the site area experienced between 6 and 8 aorms which depo <ited ice glaze 0.25 inch or more The temperature regime of the region is influenced by g;4 the proximity of the adjacent waters and as such shies not exhibit the wider diurnal an I seasonal variations of nearby 2.3.7 Storms inland locations. The average annual temperature at Tl. storm cycle in this area consists of northeasters in b
I1ymouth is 50 F with a high monthly aserage of 71*F in the Winter, thunderstorms in late Spring and Summer and E
July and low monthly aserage of 29 F in February. Th" hurricanes in the late Summer and Fall. Iligh winds in
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53 ear recon 1 of temperatures for Pty mouth is shown in 9
eaaern Massachusetts are most frequently aw>ciated with Tthie 2.3.12.
the northeasters. The maximum sustained 5-minute wind speed (not peak guets) recorded at Boston for each month 2.3.6 Precipitation are shown in Table 2.3.15.
The 20. foot level precipitation wind row for the j
Fifteen hurricanes classified as " extreme" have Pilgrim site is shown in Figure 2.315. The climatological affected the Massachusetts coastal area since 1635. In the
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Table 2.3.1 last 30 years, hurricanes classified as " extreme"(maximum
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ANNUAL STABILITY SU41\\lARY-PILGRI\\1 SITE winds greater than 136 mph) have occurred in 1938,1944, (Percent of Totai llours) 1954 (2 storms), 1955 and 1960, with a maximum sustained 5 minute wind of 87 mph at Ihton.
l Onslmre' Offshore Sescre tornado activity in castern Massachusetts is not
- Wind, Wind common. Thom8 shows a total number of seven tornadoes Cemdition NW.ESE SE.w N W Calm Total during the period of 1953-62 in a 1* square which includes the site. These torna h es did not inflict major damage. ihe
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Moderately Stable 3.8 12.1 0.2 16.1 proximity to the ocean and the terrain in the vicinity of the l
Slightly Stable' h.8 l13 0.1 21.3 site are unfavorable to severe tornado activity.
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j lh' Mmlerately plus Slightly Stable 10.6 26.5 0.3 37.4 2.3.8 Summary iloster Imersion The meteorology of the Pilgrim site is typical of a New
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Frniuency' 23.1 England coastal location with generally favorable I
atmospheric diffusion ronditions.
NOTE:
On-site wind and air temperature measurements taken f
- 1. Direction taken from 3 2.12pc rate exceeds t.5,00 feet MSL elevation.
over a one year period indicate that moderately stable or C per 100 meters.
3.11pse rate between -0.5 C and 1.5 C per 100 meters.
alightly stable atmoapheric conditions with on-shore winds C
are observed 8.7/c_.pf the time. These figures compare with I precipitation quantities in castern Massachusetta show that an inversion frequency of 23% for all wind directions for the region does not have a wet or a dry season. Monthly the North Atlantic States given by llosler.'
e.
averages vary from about 3 inches to 4V: inches at The most frequent wind directions are from SSW Plymouth. Summer precipitation is generally in the form of through WNW which are all offshore directions occurring showers or thunderstorms while most Fall, Winter and 53,Y of the time. The frequency of calm is 0.43E The site Spring precipitation comes from storms which track past experiences onshore winds 36% of the time and offshore the region. Large rainfall amounts in a short period of time winds 63.6% of the time.
2.3 2
PNPS For a ty pical 22h elegree sector, summarizing wind September,1938. A total of seven tornadoes base been
.lirection persistante: 52% of all cases obsened were for reported during the period 1953 through 1962 in a 1. degree only I hour. 72% were 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or less,90% were 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or
$1uare which includes the site; however, they inflicted less and 99% were 131:our or less. The longest period minor damage and could not be considered severe. liigh oh3encil was 39 hours4.513889e-4 days <br />0.0108 hours <br />6.448413e-5 weeks <br />1.48395e-5 months <br />, ai, i that was associated with an winds at the site are most freiluently associated with offshore wiml.
" northeasters."
Since 1938, six hurricanes classified as " extreme" have The effects of diffusion climatology at the site on radioactive discharges from the station are desenhed m passed the area. The masimum sustained 5 minute wind Appendix E, " Station llelease 1.imit Calculation,'.md spred reported at lloston due to hurricane was 87 mph in Section 14," Station Safety Analysis."
f Table 2.3.2 l
CO.\\lPARISON OF SEASONAL INVERSION FREQUENCIES (Percent of Possible flours)
Total l
Onshore Offshore llosler
- Wind, Wind Total
- 1. rersion
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Season NW.ESE SE.WNW Calm Winds Freiluency Winter 41oderately Stabit 2.3 5.7 0.1 11.1 Slightly Stable 5.7 10.7 16.4 i
Sub-Total II.0 16.4 0.1 24.5 20-40 Spring 4toderately Stable 3.3 12.4 0.2 15.9 i
Slightly Stable 5.5 11.6 0.1 17.2 j
f Sub-Total
- 11. 8 24.0 0.3 33.1 15 25 Summer 41oderately Stable 4.4 1 11. 0 0.2 22.6 Slightly Stable
- 11. 4 17.7 0.2 26.3 Sub-Total 12.!!
35.7 0.4 4 11.9 10 20 Full 41oderately Stable 5.11 12.2 0.1 1 11. 1 Slightly Stable
- 11. 3 1 11. 7 0.1 27.1 Sub-Total 14.1 30.9 0.2 45.2 2 0. 15 NOTE: Same notes as Table 2.3.1.
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- is more than 0 but less than 0.l*4 4
2.0-3
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Table 2.3.3 ANNUAL WIND SUMM ARY-PII. GRIM SITE-ELEVATION 300 FEET MSL MODERATELY STA8LE, LAPSE RATE EXCEEDS 1.5'C PER 100M j
(Percent of Observations, May 1%8-April 1969) f i
Wind Wind Speed (mph)
Direction 13 47 8 12 12 18 19 24 25 31 32 38 Total F
N
, 0.16 0.39 0.78 1.33 0.24 0.0 0.0 2.90 NNE 0.31 0.78 0.63 0.63 0.16 0.0 0.0 2.5 I e
NE 0.24 0.86 1.33 0.63 0.0 0.0 0.0 3.06 ENE 0.0 1.18 1.02 0.71 0.0 0.0 0.0 2.90 L
E 0.16 0.71 0.78 0.08 0.0 0.0 0.0 1.72 If ESE 0.08 1.10 1.02 0.08 0.0 0.0 0.0 2.27 i
SE 0.24 1.18 1.25 1.57 0.08 0.0 0.0 4.31]
{
SSE 0.24 0.86 0.86 1.49 0.55 0.0 0.0 4.00 t
S 0.0 0.31 1.65 1.25 0.31 0.0 0.0 3.53 I
SSW 0.24 1.80 3.92 7.21 3.29 1.65 0.08 18.18 SW 0.24 0.71 1.96 4.08 6.43 1.65 0.0 15.05 f
WSW 0.16 0.71 1.88 4.94 2.90 0.39 0.0 10.97 W
0.24 0.71 2.04 5.64 1.57 0.0 0.16 10.3&
j WNW 0.24 0.63 3.45 3.21 1.18 0.16 0.08 8.93 NW
- 0.08 0.86 2.12
~.27
~0.31 0.08 0.0 5'.72 '
I 2
NNW 0.08 0.63 0.94 0.78 0.16 0.0 0.0 2.59 I
Calm 1.02
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Total 2.66 13.40 25.63 35.89 17.16 3.92 0.31 100 C
NOTE: Total nu.nber of valid olucrvations is 1276.
f' Nurnber of mining olmervations is 193.
Cases this stability class are 16.1% of total obwrvations.
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PNPS Table 2.3.4 ANNUAL WIND SUMM ARY-PILGRIM SITE-ELEVATION 300 FEET MSL SLIGilTLY STABLE, LAPSE RATE BETWEEN -0.5'C AND 1.5*C PER 100M (Percent of Observations, May 1%8-April 1%9)
Wind Wind Speed (rnph)
's -
Direction 13 47 8 12 13 18 19 24 25 31 32 38 39 50 51 75 Total
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N 0.0 0.65 0.82 1.24 0.53 0.18 0.24 0.18 0.0 3.83 NNE 0.06 0.59 0.77 0.71 0.24 0.29 0.12 0.12 0.0 2.89 NE 0.12 0.59 0.71 0.29 0.18 0.24 0.29 0.0 0.0 2.42 C
ENE 0.12 0.65 1.47 1.30 0.18 0.12 0.06 0.12 0.0 4.01 E
0.06 1.06 1.06 0.53 0.41 0.47 0.06 0.0 0.0 3.65 ESE 0.18 0.71 1.53 1.00 0.47 0.29 0.12 0.0 0.0 4.30 SE 0.12 0.35 2.42 0.94 0.29 0.0 0.06 0.0 0.0 4.18 SSE 0.12 0.35 0.35 0.94 0.47 0.0 0.0 0.0 0.0 2.24 S
0.0 0.41 0.59 0.94 0.71 0.0 0.0 0.0 0.0 2.65 SSW 0.12 0.65 2.83 6.72 3.77 1.00 0.0 0.0 0.0 15.09 SW 0.06 0.12 1.00 3.18 3.59 0.71 0.06 0.0 0.0 8.72 WSW 0.06 0.53 1.77 4.18 3.12 0.35 0.06 0.0 0.0 10.08 W
0.18 0.71 1.77 5.66 4.60 0.82 0.41 0.06 0.0 14.20 WNW 0.12 0.47 2.24 4.66 1.89 0.59 0.18 0.0 0.0 10.14 NW 0.06 0.53 1.30 2.24 1.53 0.77 0.53 0.0 0.0 6.95 NNW 0.06 0.77 0.82 1.00 0.71 0.29 OE) 0.06 0.06 4.07 Calm 0.59 Total 1.41 9.13 21.45 35.53 22.69 6.13 2.47 0.53 0.06 100 NOTE: Total number of valid observations is 1697 Numler of missing olxsersations is 127 Cars this stability dass are 21.3% of total observations 2.3 5
r PNPS Table 2.3.5 ANNUAL WINO SUMM ARY-PILGRDI SITE-ELEVATION 300 FEET MSL NEUTRAL. LAPSE RATE HETWEEN -1.5 C AND -0.5 C PER 100M (Percent of Observations. May 1968-April 1969)
Wind Wind Speed (mph) l Direction 13 47 8 12 13 18 19 24 25 31 32 38 39 50 51 75 Total N
0.07 0.30 0.57 0.63 0.73 0.47 0.80 0.20 0.0 3.76 NNE 0.07 0.40 0.77 0.77 0.87 0.60 0.43 0.17 0.0 4.06 NE 0.20 0.60 0.70 1.50 1.40 0.50 0.10 0.23 0.07 5.30 ENE 0.10 0.53 0.87 1.77 1.10 0.37 0.17 0.30 0.07 5.26 I
E 0.10 0.50 1.37 1.27 0.47 0.07 0.13 0.0 0.0 3.90 ESE 0.17 0.80 1.33 1.27 0.60 0.43 0.20 0.0 0.0 4.80 SE 0.03 0.50 0.83 1.23 0.37 0.37 0.10 0.0 0.0 3.43 SSE 0.13 0.17 0.60 0.73 0.20 0.30 0.10 0.0 0.0 2.23 S
0.07 0.53 1.27 1.23 0.33 0.27 0.02 0.0 0.0 3.73 SSW 0.03 0.87 3.03 5.63 3.36 0.73 0.03 00 0.0 13.69 SW 0.20 0.37 1.27 2.10 1.43 0.67 0.0 0.0 0.0 6.03 WSW 0.07 0.33 1.23 2.66 2.83 1.17 0.27 0.0 0.0 8.56 W
0.17 0.50 1.50 3.83 2.86 1.90 0.60 0.23 0.0 11.59 WNW 0.07 0.57 1.63 2.86 3.36 1.53 1.07 0.0 0.0 11.09 NW 0.03 0.63 0.97 1.67 2.90 1.00 0.50 0.10 0.0 7.79 NNW 0.03 0.40 0.87 1.10 0.57 0.20 0.53 0.40 0.37 4.46
- Calm, 0.30 Total 1.53 7.99 18.79 30.25 23.38 10.56 5.06 1.63 0.50 10_0 NOTE: Total number of valid clarvations is 3002.
Number of missing olmervations is 129.
C scs this stability class are 37.8f of total observations.
2.3 6
PNPS j
l Table 2.3.6 ANNUAL WIND
SUMMARY
-PILGRIM SITE-ELEVATION 300 FEET MSL UNSTABLE, LAPSE RATE LESS TIIAN -1.5 C PER 100M (Percent of Observations, May 1968-April 1%9)
Wind Wind Speed (mph)
Direction 13 47 8 12 13 18 19 24 25 31 32 38 39 50 Total N
0.0 0.66 1.17 1.22 0.51 0.81 0.25 0.10 4.72 NNE 0.05 0.96 1.27 0.96 1.02 1.02 0.46 0.10 5.84 NE 0.10 1.12 1.93 1.22 0.56 0.36 0.10 0.15 5.53 ENE 0.15 1.27 2.13 0.76 0.41 0.05 0.0 0.05 4.82 E
0.25 1.37 1.68 0.30 0.20 0.05 0.0 0.0 3.86 ESE 0.10 1.32 2.69 1.27 0.10 0.05 0.0 0.0 5.53 SE 0.05 0.15 1.32 1.42 0.41 0.30 0.0 0.0 3.65 SSE 0.0 0.15 0.15 0.71 0.15 0.15 0.0 0.0 1.32 S
0.05 0.36 1.92 2.69 0.46 0.05 0.0 0.0 5.53 SSW
,0.15 0.15 3.91 5.48 2.69 0.96 0.25 0.0 13.96 SW
'[d5 0.30 1.27 3.71 2.18 0.66 0.15 0.0 8.32 WSW 0.0 0.05 1.98 3.10 1.68 0.66 0.0 0.0 7.46 W
0.0 0.46 1.17 2.23 2.89 1.37 0.30 0.0 8.43 WNW 0.0 0.51 1.32 2.03 2.59 2.18 0.41 0.0 9.04 NW 0.0 0.61 0.71 1.88 1.27 0.46 0.05 0.05 5.03 NNW 0.05 0.56 2.08 2.49 1.37 0.05 0.10 0.15 6.85 Calm 0.10
)
Total 1.02 10.36 26.70 31.47 18.48 9.19 2.08 0.61 100 4
NOTE: Total number of valid observations is 1970.
Number of missing observations is 164.
I Can this stability class are 24.8% of total observation.
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Table 2.3.7 ANNUAL WIND DIRECTION SUMMAltY llY STABILITY CLASS PILGRIM SITE-ELEVATION 300 FEET MSL (Percent of Observations, May 1968. April 1969)
Wind Moderately Sligh'ly All 1
Direction Stable Stahic Neutral l'n3 table Stabilities N
2.90 3J13 3.76 4.72 3.8 11 NNl'
- 51 2Jl9 4.06 5J11 4.00 NE 3.06 2.42 5.30 5.53 4.38 ENE 2.90 4.01 5.26 4J12 4.5 I E
I.72 3.65 3.90 3.!!6 3.49 ESE 2.27 4.30 4.80 5.53 4.47 SE 4.31 4.18 3.43 3.(>5 3.79 SSE 4.00 2.24 2.23 1.39 o a9 S
3.53 2.65 3.73 5.53 3.9 i SSW l11.1 8 15.09 13.69 13.96 14.78 SW I5.05 8.72 6.03 8.32
- 11. 6 2 WSW l0.97 1 0.011 11.5 6 7.46 9.00 W
1 0.311 14.20 l I.59
- 11. 1 3 I l.16 WNW 8.93 10.14 11.09 9.04 10.03 NW 5.72 6.9a
.. 9 5.03 6.60 NNW 2.59 4.07 4.46 6 313 4.67 Ca+'s 1.02 0.59 0.30
- 0. t 0 0.43 Total 100 100 100 100
% of total 16.1 21.3 37J1 21.8 100 NOTE: Each column adds independently to 100%. To obtain percent of total for any single category, multiply percent by percent of total for that column, e.g., N winds and moderately stable conditions occur 2 90% times 16.1%
of total or 0.47% of the total observations.
7943 valid observations,615 missing obaervations i
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PNPS Table 2.3.8a WIND DIRECTION PERSISTENCE IN 22.5 DEGREE SECTORS-PILGRIM SITE ELEVATION 300 FEET MSL (Persistence Duration in flours, May 1%8-April 1%9)
Wind Direction 1
2 3
4 5
6 7 8 9 N
97 31 16 12 1
1 2
NNE 98 29 16 6
1 7
1 1
NE 85 28 12 13 8 5 1
ENE 76 22 19 10 3 2 1 2
E 85 27 15 8
3 5 1 ESE 63 44 16 9
6 2 3 3 2 SE 93 26 17 10 4 3 1 1
SSE 82 18 5
2 3 2 1 S
99 40 17 5
1 2 3 3 SSW 109 61 52 19 21 8 7 9 6 SW 167 67 38 26 5 9 2-2 3 WSW 162 61 27 17 11 10 8 4 1 W
151 75 31 18 15 12 5 4 3 WNW 147 63 24 17 12 13 1 9 4 NW 133 49 22 13 7 5 4 3 NNW 110 34 23 11 2 4 4 Calm 24 1
1 i
Totals 1781 676 351 197 103 85 46 43 21 Table 2.3.8b WIND DIRECTION PERSISTENCE IN 22.5 DEGREE SECTORS PILGRIM SITE-ELEVATION 300 FEET MSL (Persistence Duration in ilours. May 1968 April 1%9)
Wind Direction 10 11 12 13 14 15 16 17 18 19 20 21 26 27 37 39 N
2 NNE I
I NE I
I I
ENE I
I I
i 1
1 1
E I
ESE I
I SE 1
1 SSE I
S 1
1 SSW 5
3 2
2 2
2 3
2 1
1 1
1 1
SW l
1 I
WSW l
5 1
W 3
4 2
1 2
2 1
)
WNW 3
2 1
1 1
1 1
NW 2
I I
I NNW 3
Calm Totals 18 21 10 9
7 5
4 5
4 2
0 1
2 1
1 1
2.3-9
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I PNPS Table 2.3.9 FREQUENCY DISTRIBUTION OF INVERSION PERSISTENCE PILGRIM SITE-TOTAL TOWER (Persistence Duration in llours, May 1%8-April 1969)
- llour, I
2 3
4 5
6 7
11 Frequ..ncy 159 63 38 36 20 24 21 Ill f lour, 9
10 11 12 13 14 15 16 Frcgucncy 9
il 19 21 30 12 16 15 llours 17 18 19 20 21 29 46 frequency Ii 4
2 4
5 1
1 NOTE: The longest inversion lasted 46 hours5.324074e-4 days <br />0.0128 hours <br />7.60582e-5 weeks <br />1.7503e-5 months <br /> and ended on July 2, 1968 at 1000 EST Table 2.3.10 ANNUAL WIND
SUMMARY
, ALL STABILITIES COMBINED
,3 PILGRIM SITE-ELEVAT10N 300 FEET MSL (Percent of Observations, May 1%8-April 1969)
Wind Speed in mph Direction 13 47 8 12 13 18 19 24 25-31 32 38 39+
Total N
0.05 0.48 0.81 1.02 0.55 0.42 0.42
- 0. I 4 3.88 NNE 0.10 0.64 0.87 0.78 0.65 0.54 0.30
- 0. I I 4.00 3
NE 0.16 0.77 1.11 1.03 0.78 0.33 0.13 0.13 4.36 ENE 0.10 0.M 1.33 1.25 0.55 0.18 0.08 0.15 4.51 E
0.14 0.87 I.28 0.68 0.31 0.14 0.06 0.0 3.49 ESE 0.14 0.96 1.66 1.02 0.35 0.24 0.10 0.0 4.47 5E 0.09 0.49 1.36 1.27 0.31 0.21 0.05 0.0 3.79 SSE 0.1 I 0.31 0.48 0.89 0.30 0.15 0.01 0.0 2.29 5
0.04 0.43 1.35 1.54 0.44 0.11 0.01 0.0
'I.91 SSW 0.11 0.88 3.35 6.90 3.27 0.99 0.09 0.0 14.78 SW 0.14 0.35 1.32 3.05 2.88 0.83 0.05 0.0 8.62 l
WSW 0.06 0.37 1.64 3.46 2.62 0.74 0.11 0.0 9.00 W
0.14 0.57 1.56 4.12 3.03 1.23 0.42 0.10 11.16 WNW 0.09 0.54 1.98 3.10 2.50
'I.27 0.55 0.0 10.03 NW 0.04 0.64 1.16 1.94 1.79 0.67 0.31 0.05 6.60 NNW 0.05 0.55 1.17 1.37 0.73 0.15 0.29 0.35 4.67 Calm 0.43 TOTAL 1.56 9.69 22.42 32.59 21.02 8.21 3.01 1.08 100 NOTE: Number of valid observations is 7945 Number of missing observations is 615 2.3 10
PNPS Table 2.3.11a Table 2.3.11c SIGMA.TilETA U.BAR, ALL STABILITIES, SIGMA TilETA U-BAR, ALL STABILITIES, ELEVATION 300 FEET MSL, PILGRIM SITE, ELEVATION 300 FEET MSL, PILGRIM SITE, M AY 1%8-APRIL 1%9 MAY 1%8-APRIL 1%9 (u = 13 mph)
(u = 812 mph)
Cumulative Cumulative 00g Frequency Percent Frequency Percent o0ii Frequency Percent Frequency Percent 0.0 7
11.7 7
11.7 0.0 0
0.0 0
0.0 0.05 13 21.7 20 33.3 0.05 27 4.2 27 4.3 0.1 19 31.7 -
29 65.0 0.1 37 5.7 64 9.9 0.2 15 25.0 54 90.0 0.2 35 5.4 99 15.3 0.3 3
5.0 57 95.0 0.3 93 14.4 192 29.7 0.4 2
3.3 59 98.3 0.4 110 17.0 302 46.7 0.5 1
1.7 60 100 0.5 96 14.8 398 61.5 0.6 89 13.8 487 75.3 NOTE: 00 in radians, p in reeters per second.
0.7 56 8.7 543 83.9 0.8 41 6.3 548 90.3 0.9 30 4.6 614 94.9 Table 2.3.llb I.0 8
1.2 622 96.1 SIGMA.TilETA U.BAR, ALL STABILITIES, i'1 12 1.9 634 98.0 ELEVATION 300 FEET MSL, PILGRIM SITE, 4
0.6 638 98.6 e
}{o M AY 1%8-APRIL 1%9 l3 3
0.5 641 99.1 (u
rnph) 1.4 4
0.6 645 99.7 1.5 0
0.0 645 99.7 Cumulative
.6 1
0 99 00ii Frequency Percent Frequency Percent 00 99 1.8 0
0.0 646 99.8 0.0 0
0.0 0
0.0 1.9 0
0.0 646 99.8 0.05 16 5.0 16 5.0 2.0 0
0.0 646 99.8 0.1 24 7.5 40 12.6 2.1 1
0.2 647 100 0.2 55 17.3 95 29.6 0.3 83 26.1 178 56.0 0.4 43 13.5 221 69.5 0.5 58 18.2 279 87.7 0.6 18 5.7 297 93.4 0.7 9
2.8 306 96.2 0.8 4
1.3.
310 97.5 0.9 5
1.6 315 99.1 1.0 0
0.0 315 99.1 1.1 1
0.3 316 99.4 1.2 1
0.3 317 99.7 1.2 1
0.3 318 100
)
2.3 11
PNPS Table 2.3.1Id SIGMA.TilETA U.BAR, ALL STABILITIES, ELEVATION 300 FEET MSL, PILGRIM SITE, M AY 1%8-APRIL 1%9 l
(Wind Speed in mph) 1 j
13 - 18 19 - 24 25 - 31 Cum.
Cum.
Cum.
00ii Frequency % Frequency % Frequency %
0.0 0
0.0 0
0.0 0
0.0 0.05 0
0.0 0
0.0 0
0.0 0.1 33 4.3 9
30 0
0.0 0.2 54 11.4 1
3.4 1
2.1 0.3 23 14.4 15 8.4 2
6.3 0.4 91 26.6 0
8.4 2
10.4 0.5 81 37.2 37 20.9 0
10.4 0.6 66 45.8 29 30.9 0
10.4 0.7 113 60.6 22 38.2 11 33.3 0.8 76 70.5 28 47.6 1
35.4 0.9 62 78.6 25 56.1 0
35.4 1.0 40 83.8 30 66.2 16 68.8 1.1 31 87.9 20 73.0 3
75.0 1.2 39 93.0 20 79.7 1
77.1 1.3 12 94.5 8
82.4 1
79.2 1.4 15 96.5 12 86.5 2
83.3 1.5 15 98.4 13 90.9 2
87.5 1.6 5
99.1 13 95.3 2
91.7 1.7 0
99.1 5
97.0 2
95.8 1.8 2
99.3 3
89.0 0
95.8 1.9 1
99.5 2
98.6 0
95.8 2.0 1
99.6 1
99.0 2
100 2.I I
99.7 I
99.3 2.2 0
99.7 0
99.3 2.3 1
99.9 1
99.7 3.3 11 100 0
99.7 3.7 0
0 1
100 2.3 12
j PNPS Tabic 2.3.12 TEMPER ATURES-PLYM0UTil, M ASS.
( F)
Jan.
Feb. Mar. A pr.
May June July Aug. Sept. Oct.
Nov.
Dec.
Annual Mean Maximum 38 38 45 55 66 74 79 77 71 62 52 41 58 Mean Minimum 25 23 29 37 46 55 62 61 55 46 37 29 41 Daily Average 30 29 37 46 56 65 71 69 62 53 43 33 50 Extreme Maximum 68 71 87 91 94 102 102 102 100 87 82 67 102 Extreme Minimum
-8
-14 0
15 27 33 44 41 32 23 10
-14
-14 Table 2.3.13 PRECIPITATION-PLYM0UTil, M ASS.
J an.
Feb. Mar. Apr. May June July Aug. Sept. Oct.
Nov.
Dec.
Annual Normal, Inch 4.22 3.46 4.53 4.13 3.43 3.34 2.92 4.22 3.90 3.53 4.50 4.05 46 Mean No. Days
>0.10 inch 7
6 8
8 7
6 6
4 a
6 7
9 82
>0.50 Inch 4
4 3
3 2
1 2
4 2
3 3
4 35 24.hr. Maximum, Inch 2.75 2.37 3.01 2.76 3.28 5.68 4.13 4.14 6.88 4.12 4.36 3.53 0
Table 2.3.14 SNOWFALL - BOSTON, M ASS.
Jan. Feb. M ar.
Apr. May June July Aug. Sept. Oct.
Nov.
Dec.
Annual Monthly Average, Inch 12 12 7
2 T
0 0
0 0
T 2
7 42 Monthly Maximum, Inch 36 35 33 28 T
0 0
0 0
1 18 27 36 24.hr. Maximum, Inch 15 16 13 9
T 0
0 0
0 1
12 12 16
^
Mean No. Days
>l.0 inch 4
3 2
0 0
0 0
0 0
2 II T - Trace
- - Less than 0.5 inch Table 2.3.15 M AXIMUM SUSTAINED 5. MINUTE WIND SPEED (BOSTON, M ASSACilUSETTS)
Month Year Direction Speed (mph)
January 1945 SW 66 d
February 1940 NE 58 March 1947 E
73 April 1935 NE 63 May 1935 W
55 June 1935 NW 46 July 1935 NW 52 August 1947 NE 52 September 1938 S
87**
)
October 1933 NW 63 November 1950 SE 80 December 1934 W
73
- Due to the hurricane of September 21,1938.
2.3 13 i.
. - ~..
PNPS IIEFEllENCES
- 1. Iloder, C. it., Climatological Estimates of Diffusion No. 5, S. l.t-Oct,1967.
Camditions in the United States, Nuclear Safety, luun, 11.
orna o o6abdides,. Monthly Vol 5, No. 2, Winter, 1963-1964.
W"' ' I' e r it e vie w, Vol. 91, No. 10 12, 1963, 2.
Van eie r lloven, A tmospheric Transport and Diffusion at Coastal Sites, Nuclear Safety, Vol. 8, pp 730 736.
2.3 14
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FINAL SAFETY ANALYSIS REPORT n
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ta e
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FIGURE 2.311
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%9 Neutral Lapse Rate U
o m
U 2 w" l
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- g, 5 Slightly Stable lapse Hate P' rim Site 4
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s
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SAFETY GROUP REPORT ON ENVIRONMENTAL ASPECTS OF THE PILGRIM STATION l
[
BOSTON EDISON, DOCKET NO. 50-293 i
s p
SITE AND ENVIR0! TENT A.
Geography The Pilgrim Nucicar Power Station is located 6.4 kilometers east of Plymouth, tbssachusetts.
It is on the western shore of Cape Cod Bay and just south of Plymouth Bay at a place called Rocky Point.
The 517 acre site can be described roughly as a rectangic about 700 meters wide by 3000 meters long, with the long axis oriented northwest to southeast parallel to the Cape Cod Bay shore.
The reactor building is near the northeast corner about 150 meters from the ocean, and the turbine building is southwest of the reactor about 7000 meters from the nearest inland site boundary.
t An important change since the construction permit review is that the stack has been moved further from the southwest boundary and is now clocer to the northwest boundary and the Bay.
In addition the stack is now 100 feet higher than the original design.
The dominant topographic feature in the area is the Pine Ilills, a ridge west of the site uhich runs from its northern boundary at Plymouth Bay to the south for about 6 kilometers.
From the shoreline on the northeast side the land rises to a maximum onsite height of about 90 meters above Mean Sea level (FGL) at e
i
Meteorolony The semipeninsular location on the northeast coast is the principal determinant of the major meteorological characteristics of this site.
llistorical records from Plymouth indicates that northeastern temperature extremes are moderated by the ocean heat sink.
Records at Plymouth indicate total precipitation is fairly uniform from month to month and annual rainfall is not unusually high.
Boston records indicate snowfall also is not unusually high.
The storm cycle in the area consists of thunderstorms in spring and summer, possible hurricanes in late summer and fall, and north-casters in the winter.
Although tornado frequency is not as high as in some other parts f
of the country, it is sufficiently high that the applicant has designed to protect against them, using criteria acceptabic to us, namely a design basis wind with a 300 mph tangential velocity e
and a 60 mph transverse velocity.
The prevailing westerlies generally should result in relatively good annual dif fusion characteristics, carrying gaseous ef fluents out over Cape Cod Bay, traveling about 30 kilometers before reaching Cape Cod, llowever, in spring and summer, when the water surface is relatively cooler than the land mass and produces appropriate conditions for sea breeze development, the combination of stabic lower air, onshore winds and differential heating as the air moves inland can produce fumigation conditions for gaseous material released from the plant. The occurrence of e
scabreeze - fumigation conditions has been documented by a special sm'oke release study by the applicant during the summer of 1969.
The problem is further accented by the sharp rise in elevation as the air meets the Pine Hills Ridge.
In our accident analyses we have assumed fumigation for the initial two hour period.
The applicant has been conducting an onsite meteorological program since liay 1968.
The program involves the use of a 220 foot tower (to 300 feet MSL, the height of the original stack.)
The data is adequate to determine that for the initial period, type F stability and 1 meter /sec wind speed are sufficiently conservative.
~
l l
t 1
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l.
1 I
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e-0, 7
.. PILGRIM STATION PRIMARY COOLANT RECIRCULATION SYSTEM CHEMICAL DECONTAMINATION 1.
INTRODUCTION Pilgrim Nuclear Generating Station is located on the northern shore of Cape Cod near Plynouth, Massachusetts.
The Pilgrim plant is a 670 iWe boiling water reactor (SWR) which is operated by Boston Edison Company (BECo). Pilgrim went commrcial in December 1972. Previous inservice inspections (ISI) revealed several welds in the primary coolant recirculation system (PCRS) piping that were failing due to intergranular stress corrosion. Therefore, BECo personnel determined that the PCRS would have to be replaced during the 1983-84 ref ueling outage. General Electric (GE) was contracted by BECo to oversee the pipe replacement operation. Job preplanning reviewed methods whereby wor ker dose could t]e minimized. Two options that would significantly affect man-rem savings.were chemical decontamination of the PCRS and surf ace decontamination of the drywell.
The vendor chosen for the chemical decontamination was IT Nuclear Services (IT).using the Dow NS-1 chemical system. The surface decontamination was to be performed by other contract personnel.
This report describes (a) the plant cn,emical decontamination experience, (b) decontamination factors (OFs) obtained, (c) the jobs performed on the PCRS.af ter the
~
decontamination, (d) man-rem savings, and (e) other pertinent information.
2.
PLANT PCRS DECONTAMINATION EXPERIENCE 2.1 Operational Sequence General Electric contracted IT to perform a chemical decontamination of the PCRS during the 1983-84 refueling and maintenance outage. Pilgrim station was shut down December 10, 1983, and IT personnel arrived onsite mid-December to prepare for a chemical decontamination on December 26.
S-N
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-r
, - + -
.c 7
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m
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The chemical decontamination process to be used was Dow NS-1, a proprietary process developed to remove oxide films inside PCRS piping.
IT's equipment was skid mounted and consisted of four skids, one for chemical addition and filtration, one for the recirculation pump, one for chemical cleanup using a reverse osmosis (RO) process, and the last one for process control.
All of the IT skids were located inside the secondary containment building along the trackway to the equipment hatch. The recirculation pump skid was placed near the equipment hatch while the other three skids were located nearer the trackway doors. A surge tank and a shielded radwaste shipping container were also used in the process.
The chemical addition and filtration skid and the R0 skid were enclosed by a shield wall of concrete block. The R0 units were designed to remove the metalic ions and process chemicals at the end of the decontamination with the concentrated solution going into the shielded shipping container. Process heating was supplied by BECo via a temporary boiler and a steam heat exchanger. All of the process skids and FCRS were interconnected using flexible rubber hoses.
Process procedures called for a two-loop decontamination to be performed.
The first loop was the discharge piping, ring header, and risers; the second loop was the suction lines, reactor water cleanup (RWCS) lines in the drywell, and residual heat removal (RHR) system piping in the drywell.
The flow path of the first loop was from one discharge pipe up through the ring header and out through the opposite discharge pipe. The risers were filled and drained through the use of a surge tank. The second loop was from one suction line through the annulus and back out the opposite suction line. The RWCS and RHR lines were also decontaminated during the second loop decon by use of side flow loops off the suction lines.
System liquid levels were maintained using visual checks of fluid level in tubing that was connected between the recirculation pumps and a reference point of in terest.
During the preoperational phase, there were several delays in schedule as a result of-refueling complications, decontamination equipment malfunction, coordination of plant personnel, and plant support operations.
Several of 2
the significant problems are discussed in Section 2.5.
As a result of these problems, the actual chemical decontamination did not start until January 29, 1984 The systs was brought up to temperature and pressure, i.e., 250*F and 30 to 35 psig, early on the 29th, with the first NS-1 injection into the system late in the evening of the 29th. Daring the next 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> four batches of NS-1 chemicals were injected.
The decontamination solution was circulated in both the discharge and suction loop components over the next four days until Thursday February 2.
On Thursday the system temperature was decreased to 115 to 130*F and the system depressurized.
When the system temperature and pressure were stabilized a copper removal step was performed. By late Thursday the chemical decontamination was complete, and the chemical removal step was initiated using the RO units.
Within a short time period the flow through the RO units decreased significantly, and it was determined that another chemical removal
. technique would need to be employed. Final resolution of the problem was to bring ion exchange resin columns onsite and pass the system liquids l
through the resin beds to remve metal ions and chemical components.
During the cleanup phase approximately 300 gallons of contaminated water were released to the torus. This water was later cleaned using Chem-Nuclear ion exchange resins.
2.2 Material Removed During the PCRS decontamination, samples of the circulating solution were obtained by IT personnel. Initially, the samples were taken on a two-hour schedule and then later at three-hour intervals.
These samples were analyzed by IT chemistry personnel for metal ions, chemical parameters, and 60Co activity.
The results of the sample analyses were used to maintain proper chemistry, evaluate metal ion removal, and determine activity removed. A final sample was obtained at the end of the decontamination steps, prior to cleanup, for 10 CRF Part 61 analysis requirements by an outside vendor. The results of the radionuclides removed are listed in Table Bl.EI) 3
~
The following statements summarize the data in Table 81.
55 o
Fe accounts for 39% of the total activity removed.
60 o
Co accounts for 49% of the total activity removed.
o Total activity renoved from the system 93 C1.
o Total gamma emitting activity removed from the system 56 Ci.
60 o
Co accounts for 81% of the gamma emitting activity removed.
TABLE B1 RADIONUCLIDES REMOVED DURING PCRS CHEMICAL DECONTAMINATION Radi onuclide PCRS Total Ci 54Mn 3.86 55Fe 36.20 58 Co 3.25 60 Co 45.71 63Ni 2.38 0
)
Zn 0.89 Other 0.81 Total 93.10 l
4
.?
2.4 Waste Generated 2
During the chemical decontamination operation two types of wastes were generated.[2] Waste liquids that were highly concentrated wera generated j
from the use of the R0 units.
Approximately 1300 gallonsEI) of liquid 3
were created from R0 operation. Al so, 90 f t of mixed bed resins (i.e.,
anion and cation) were generated in cleaning the remaining decontamination so lu tion. These two waste forms were solidified by Chem-Nuclear using 3
their mobile solidification unit.
Of the resin, approximately 35 f t were held to be solidified with resins generated in a reactor water cleanup system decontamination performed by Pacific Nuclear.
The final volume of PCRS cement solidified wastes was 480 f t3 from the liquids and 127 f t from the resins.
Both waste forms were later sent to Barnwell, South Carolina, for burial.
I 2.5 Problems Encountered During the preoperational phase of the chemical decontamination there were many situations that arose that resulted in schedule delays. These I
situations were not all directly related to the chemical decontamination process but were either steps that had to be performed to clear the way for the decontamination or other plant operations.[3] These situations will I
not be itemized; however, a lesson to be learned from the plant experience is that scheduling and coordination of activities needs to be closely followed and coordinated with al1 personne1.
Situations that arose and resulted in long delays (i.e., greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />) in the chemical decontamination schedule were many.[4,5]
A cooling heat exchanger on the chemical injection skid did not pass a preoperational test.
It was found that several of the tubes had failed as a result of shipping the heat exchanger with fluid inside. A new heat exchanger was located and installed. There was also a disagreement early on with the liquid level indicator readings between BECo and IT. The disparity was resolved by having a survey crew brought in to establish correct elevations.
5
j There were many clamp f ailures on the rubber flexible hoses that were used J
to interconnect all skids and the PCRS. A decision was made to replace all of the rubber flexible hoses with either stainless flexible hoses or to replace the rubber hose clamps.
It is interesting to note that all f ailures were at connections and not in the body of the hose. A final hose connection f ailure resulted during the pre-decontamination heatup. A flexible rubber hose line located near the reactor head area was used to provide the 30 to 35 psig nitrogen overpressure for the decontamination process.
When the other hose clamps f ailed, and prior to this f ailure, a decision was reached not to replace this line as replacement would necessitate depressurizing the system, refilling the reac tor vessel, and i
removing some shielding. However, during the hot function test the hose clamp f ailed when the systen was at 255 F.
The f ailure caused system depressurization and a resultant loss of temperature. The replacement of the rubber hose with stainless flexible hose required complete system cooldown and refilling of the reactor vessel, with the vessel being drained and the system repressurized before the decontamination could proceed.
Another problem area was with the decontamination system pumps. The recirculation pump seal f ailed, was replaced, and f ailed a second time.
After the second failure the pump was replaced by a BECo-owned pump that was onsite. When the new pump was started, the power load from the pump tripped the circuit breaker. A new service was brought in and the 1
recirculation pump was tested ~successfully. However, during the preoperational testing, it was found that the output pressure of the chemical injection pump was not large enough to overcome the recirculation pump backpressure.
This problem was solved by replacing the chemical injection pump with a larger pump.
A last failure to be discussed occurred at the end of the chemical decontamination. The R0 units initially functioned as normal, but flow through the units dropped off until it was obvious the system cleanup would extend too long into critical path time.
Therefore, it was decided to have ion exchange units brought onsite by Chem-Nuclear to finish cleaning the chemicals and metal ions out of the circulating solution. It was felt that 6
the R0 skid f ailure was the result of an overpressurization in the R0 units during a preoperational pressure test of the system.
The f ailure also impacted the final waste handling process as both liquids and resins were l
finally solidified.
3.
DECONTAMINTION FACTORS 3.1 Plant Data Radiation surveys of the PCRS piping were performed by BECo health physics staff, and by IT and GE personnel both pre and post decontamination. Each group used a different survey instrument for their measurements.
BECo personnel used t.n Eberline R0-2 which is a GM survey meter; IT used a Ludlum model 360 with a high range probe that was put in a 2-in. lead shield with a 3/8-it'. collimated hole; and GE used an Eberline PRS-1 with
]
an HP220A probe. The MP220A probe is a small GM detector in a 2 tungsten j
shield.
BECo personnel surveyed 19 points both pre and post decon wnile l
IT and GE personnel surveyed 13 points both pre and post decon.[6] The results of these neasurements are listed in Tables B2 and B3 for the BECo and IT/GE surveys, respectively. There were some general area surveys made both pre and post decontamination; however, the surveyed areas were not the same both pre and post decontamination.
Figure B1 has been included to i
assist the reader in survey point correlation.
Applicable decontamination data from Tables B2 and B3 are shown in Figure B2. Figure B2 is a schenatic of the PCRS piping, included as a j
comon format for all sites visited during our study. Table B4 lists the median value DFs and ranges for the (a) risers, (.b) suction and discharge pipes, (c) pump suction and discharge elbows, and (d) total system.
The median values are determined by nunerically ranking ~ the individual DFs and using the central value.
A review of the data in Tables B2 and B3 shows significant differences in the pre-and post-decontamination neasurements for the same survey points.
7 l
TABLE B2 PILGRIM RECIRCULATION PIPING DECON SURVEY RESULTS (BECo Data)
A Looo B Leco Initial Final Initial Final Survey Point, (mR/hr)
(mR/h r)_
DF Survey Point (mR/hr)
(mR/h r)
DF N2D Top 6 00 35 17 NlA Back 6 00 40 15 Middle 650 50 13 N2K Top 1,000 150
- 6. 7 Bottom 500 50 10 Botto m 900 140 6.4 N2C Top 800 50 16 N2J Top 800 100 8
Middie 750 120 6.2 Bo ttom 800 50 16 Bottom 250 60 4
N2H Top 600 45 13.3 N2h Middle 1,000 3 20 3
Middle 800 120 6.7 Bottom 800 140 5.7 Bottom 270 50 5.4 N2F Bottom 800 60 13.3 Ringheader Side 500 60 8.3 End 350 60 5.8 Pump Outlet 400 80 5
Discharge Line 400 40 10 after MOSA 23-f t Elevation TABLE B3 PILGRIM RECIRCULATION PIPING DECON SURVEY RESULTS (IT/GE Data)
A Loop B Loop Initial Final Initial Final Survey Point (mR/hr)
(mR/hr)
DF Survey Point (mR/hr)
(mR/hr)
DF N2A Bottom 110 73 1.5 N2F Middle 110 22 5
Bottom 80 18 4.4 Inlet to Pump 345 49 7
Ringheader Side 80 18 4.4 before M04A N2H Middle 110 20 5.5 Bottom 100 18 5.5 Pump Inlet 476 192 2.5 Pump Inlet 140 54 2.6 after M04A before M04B Pump Inlet 1 30 70 1.9 Pump Outlet 268 42 6.4 after M04B after MO5A Pump Outlet 316 205 1.5 before M05B Discharge Line 340 11 31 23-f t Elevation 8
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T'hese differences are the result of the different instruments and shield configurations used to perform the surveys. There are also differences in the measurements within each table for a similar survey point. These differences may be due to associated piping that was not decontaminated or had high external contamination. There is little that can be said concerning comparisons of the data between the two tables due to the lack of identical points surveyed by both BECo and IT/GE.
One point that can be made is that in general the DFs calculated on Table 83 are smaller than the DFs in Table B2 for the same locations.
This is probably due to the use of the IT detector with its small collimated shield. An arithmetic (DF )
A and weighted harmonic (DF ) mean DF were calculated for smaHer system H
subsections using applicable data in both tables, and are listed in 1
Table 85. These values can be compared to the single DF of 10 reported A
by GE or a DF f 9.3 and DF f 12.7 calculated by au% ors.
Rey can A
H also be compared to the median DFs listed in Table B4, where the median DFs are smaller in most cases.
TABLE B5 ARITHMETIC AND WEIGHTED HARMONIC MEANS 0
Subsection Description A
H Risers 10 7.1 Ringheader 8.3 7.7 Suction Elbows at Vessel 15
- 15
- Suction / Discharge Piping 10*
10*
(verticle runs)
Suction / Discharge Piping 3.6 2.7 (near recirculation pumps)
Single measurement.
l 12 i
In general, the reporting of DFs by subsections tends to nore clearly depict the actual decontamination effectiveness of the system, as can be seen by comparing the DF of 12.7 for the single value DF to the riser g
and ringheader DF s which are smaller but yet where most of the g
naasurement data were obtained. An extrene is seen in comparing the 12.7 DF to the suction / discharge piping near the recirculation pumps H
where DF was 2.7.
g During the insulation removal, several sections of insulation were brought out that were highly contaminated (i.e., > 200 mR/hr at contact), also there were several sections of nondecontaminated piping that were removed that were contributing to the drywell background. Therefore, IT personnel requested that several pieces of the PCRS piping be sent to them af ter renoval from the drywell in an attempt to determine how effective the chemical decon was.
Table B6 lists the ranges of the DFs by subsections from the plant data and the IT laboratory measurements.[7] As can be seen, the lab DFs are significantly greater in all subsections except for the riser elbows, indicating there were significant background inter-ferences in the pre-and post-decontamination neasurements.
TABLE B6 RANGES OF PLANT AND LABORATORY DFS S ubs_ec_ti on P1 ant DF Laboratory DF Riser Elbow 7 to 16 8 to 16 Riser 3 to 13 47 to 100 Ringheader 6 to 13 21 to 31 Suction / Discharge 5 to 10 11 to 100 1
13
3.2 Man-Rem DFs Plant Data A man-rem DF was calculated by GE[6] using comparisons of average dose per unit tine received by the survey personnel both pre and post decon.
The average dose per hour was 195 mrem /hr pre decon and 66 mrem /hr post decon. This results in a man-rem DF of 2.9.
3.3 EG&G Data There were no neasurements made by EG&G Idaho personnel at Pilgrim station as this decontamination was the first observed decontaminatial. As a result of the experience gained during the observations, EG&G Idaho personnel were able to determine what types of measurements they would start to make during future observations.
4.
ALARA CONSIDERATIONS Prior to performing the chemical decontamination, other techniques were reviewed which would add to the total man-rem savings.[8] Some of the techniques that were implemented were removing the f uel, having the vessel cavity full of water, removing the peripheral control rods, and driving the inner control rods into the vessel approximately four feet. Changing the position of the control rods moved the stellite bearings, which in an older reactor have been neutron activated to produce many curies of 60Co, farther from the safe end penetrations of the risers and suction nozzles.
Also, as earlier mentioned, an in-depth evaluation on decontaminating the drywell surfaces was perforned. The result of this evaluation was that an estimated 133 man-rem could be saved by performing a drywell surf ace decon.
GE personnel estimated that it would require 3840 man-rem to remove and replace the PCRS piping without any decontamination. They estimated that with a chemical decon of the PCRS, it would require 898 man-rem, and with an added drywell decon it would require 130 man-rem to remove and replace 14 3
the PCRS piping. The actual dose expended in performing the PCRS pipe replacement was 1785 man-rem.
This figure is higher than the GE estimate partly because of extensive nozzle repair that was not scheduled at the time of the GE estimate. A breakdown of the total man-rem expended by craft is listed in Table 87.E93 The nan-rem expended by IT personnel in performing the chemical decontamination was 6.11 man-rem, and the highest individual dose was 0.97 man-rem.El3 Final man-rem savings estimated from the chemical decontamination and drywell decon was 3500 man-rem.
Table B7 MAN-REM AND MAN-HOURS EXPENDED IN PCRS PIPE REPLACEMENT Job Performed Man-R em Man-Hours Chemical Decon 53.0 5229 Mobilizati on 30 1.3 16505 Pipe Removal 107.2 6832 Pipe Replacement 526.3 38603 1
Res toration 20 4.0 19943 Inspecti on 136.7 10228 Area Decon 10 3.9 8531 HP Support 69.3 5567 Miscellaneous Support 45.1 11233 1
Non-Rad Support 238.0 1
Total 1784.9 122671 i
- No available information.
During the actual pipe replacement there were several techniques used that benefited ALARA. Extensive use of mockups was performed to f amiliarize the workers with the job to be perforned. Automated cutting and welding machines were used where possible. Pipe removal was also performed using plasma arc cutting. To reduce airborne contamination from the plasma cutting, small tents, of non-flammable material, were constructed around the area where the cutting was to be perforned,.and then a flexible ventilation duct was attached to the tent.
This tent technique effectively 15
prevented an increase in drywell airborne contaminant levels.
Replacement pipe design and system f abrication also added to reduced man-rem for replacement and will be a definite factor in future drywell PCRS work. A few of the design changes were use of 316 SS piping, which is a low carbon contaminate steel; mechanical polishing of the replacement pipe ID, 50 fewer welds, and more strategic placement of welds to make ISI easier.
5.
LESSONS LEARNED As a first time vendor, IT personnel learned much from this experience.
Some of the lessons learned center around quality control.[4,5] Several of the equipment f ailures experienced by IT were the result of using equipment that had either not been properly checked out prior to shipment or were not properly prepared for shipment. Furthernore, when they were brought on site the system was not given preoperational testing early after a ss enbly. Another item that reflects lack of quality control, but was outside the vendor's purview, was the rubber flex hoses and clamps used in the process. Due to the numerous f ailures experienced, it was obvious that no proper quality review had been performed on these hoses or clamps.
Also, the f ailure of the R0 unit seems to reflect improper understanding of the equipment function on the part of those who either developed test specifications or performed the pressure test of the assembled equipment.
In discussions with IT personnel they stated that both BECo, GE and IT personnel had problems that seriously impacted the decontamination schedule.
BECo personnel also reflected similar ideas concerning lessons learned.E93 Also, there were delays due to outage coordination among different project task leaders; therefore, it is important to work closely with all personnel.
16
- 7 _-
e REFERENCES 1.
Letter from.B. Thomas, IT Nuclear, to B. Jones, BECo,
Subject:
Analysis of Radioactive Waste at Pilgrim, March 22, 1984.
2.
D. Thorpe, private communication, Chem-Nuclear, June 1985.
3.
J. Nicholson, private communication, Boston Edison Co., January 1984.
4.
B. Armstrong, private communication, Boston Edison Co., February 1984.
5.
B. Arrowsmith, private communication, IT Nuc. lear, February 1984.
6.
Letter from P. K. Bingham, G.E.,
to J. Nicholson, BECo,
Subject:
Pilgrim Piping Replacement Project Decontamination Factor Resulting from the Chemical Decontamination, February 23, 1984.
7.
D. Harmer, private' conmunication, IT Nuclear, 19 84.
8.
G. E. Powers, private communication, GE, January 1984.
9.
B. R. Hoey "BWR Recirculation Pipe Replacement: Panel Discussion,"
Health Physics Society Meeting, Chicago, Illinois, May 27-31, 1985.
17
7, 9-
.' g a
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/
Pilgrim Unit 1 Iodine Vent Release The Technical Specification limit for the release of radioactive iodine from the Pilgrim Unit I reactor building exhaust vent was established in 1972 at the time of the issuance of the Operating License.
This limit was determined using an extremely conservative calculatiohal model that assumed a MPC reduction factor of 700 to account for Iodine 131 reconcentration in the grass-cow-milk childs thyroid chain. The limit was further based upon the assumption that the exposure path for iodine uptake in a childs thyroid was through an hypothetical cow located continuously at the site boundary in the compass sector which meteorological calculations predict the highest annual average concentration J
would occur.
In addition to the quantitative conservatism of these calculated limits, additional conservatism existed because the specifications did not permit the releases to be averaged over a 13 week interval as is permitted by effluent release specifications being currently issued by the Commission.
During the week beginning January 7, 1975 the iodine release rate from Pilgrim 1, averaged over a 7 day interval, exceeded the technical specification iodine release limit.
Boston Edison instituted a comprehensive investigation to identify the source of the releases from the reactor building and to climinate these reIcases where possible.
Boston Edison has tentativefy concluded that the main contributors to the releases are in the radioactive waste treatment system and is actively pursuing an engineering solution to reduce these releases.
On April 2, 1975 Boston Edison proposed changes to its iodine release limits N
which would permit some operational flexibility by identifying remedial actions to be taken in the event that the release rate limits are exceeded in a seven day interval.
The Regulatory staff reviewed Boston Edison's proposed change and determined that additional modifications to the proposed specifications were necessary.
On May 22 Boston Edison submitted a supplement to its proposed change which incorporated iodine release limits calculated according to the Comnission's current guidelines relating to as-low-as-practicabic considerations. These new specifications contain iodine release limits determined using the more realistic calculational model contained in Regulatory Guide 1.42 (March 1974). This model takes into account the location of the nearest real cow located 5600 meters to the west of the site rather than a hypothetical cow at the site boundary.
The new specification also permits averagir.g the iodine release over a calendar quarter rather than over a seven day period as previously required.
These new iodine release specifications were issued on May 23, 1975 and assure that the releases of iodine from Pilgrim Unit I will be maintained as low as practicable, in accordance with Commission guidelines while eliminating repetitive violations of an overly conservative technical specification that was based upon unrealistically conservative, hypothetical assumptions.
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