ML20151L650
| ML20151L650 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 07/22/1988 |
| From: | Gallo R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Bird R BOSTON EDISON CO. |
| Shared Package | |
| ML20151L657 | List: |
| References | |
| NUDOCS 8808040101 | |
| Download: ML20151L650 (2) | |
See also: IR 05000293/1988011
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JUL 221988
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Docket No. 50-293
Boston Edison Company
ATTN: Mr. Ralph G. Bird
Senior Vice President - Nuclear
Pilgrim Nuclear Power Station
RF0 #1 Rocky Hill Road
flymouth, Massachusetts 02360
Gentlemen:
Subject:
Inspection No. 50-293/88-11
This refers to your letter dated June 21, 1988, in response to our letter dated
May 17, 1988.
Thank you for informing us of the actions taken to resolve the issues
identified from the E0P inspection. Your actions taken to resolve several of
the items were reviewed in inspection 50-293/88-19.
Those not yet examined
will be re" %d in a future inspection of your licensed program.
Your cooperation with us is appreciated.
Sincerely,
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Robert M. Gal o, Chief
Operations Branch
Division of Reactor Safety
cc:
K. Highfill, Station Director
R. Anderson, Plant Manager
J. Keyes, licensing Division Manager
E. Robinson, Nuclear Information Manager
R. Swanson, Nuclear Engineering Department Manager
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The Honorable Edward J. Markey
The Honorable Edward P. Kirby
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The Honorable Peter V. Forman
B. McIntyre, Chairman, Department of Public Utilities
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Chairman, Plymouth Board of Selectmen
Chairman, Duxbury Board of Selectmen
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Plymouth Civil Defense Director
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P. Agnes, Assistant Secretary of public Safety, Commonwealth of Massachusetts
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S. Pollard, Massachusetts Secretary of Energy Resources
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R. Shimshak, MASSPIRG
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Public Document Room (POR)
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Local Public Document Room (LPOR)
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Nuclear Safety Information Center (NSIC)
NRC Resident Inspector
Commonwealth of Massachusetts (2)
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6800040101 800722
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Boston Edison Company
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Region 1 Occket Room (with concurrences)
M. Perkins, Management Assistant, DRMA
S. Collins, DRP
R. Blough, ORP
L. Doerflein, DRP
R. Sores, DRSS
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0FFICIAL RECORD COPY
RL PILGRIM 88-11 - 0002.0.0
07/19/88
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SOS 70A'aiWCW
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Pilgrim Nuclear Power Station
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Rocky Hill Road
Plymouth Massachusetts 02360
Ralph G. Bird
June 21. I988
Senior Vge President - Nuclear
BECo Ltr #88-097
U.S. Nuclear Regulatory Commission
Attn:
Document Control Desk
Hashington, D.C. 20555
Docket No. 50-293
License No. DPR-35
Subject: NRC Inspection Report 50-293/88-11
Dear Sir:
Attached is Boston Edison Company's response to the unresolved items described
in the subject inspection report.
An excerpt from the appropriate section(s) of the inspection report is first
stated, followed by the Boston Edison Company response.
The corrective action
for each of the items has been satisfactorily completed to support plant
operation.
Please do not hesitate to contact me directly if there are any questions.
hd
R.G. Bird
CS/b1
Attachment 1:
Respcose to Unresolved Items
Attachment 2:
i. valuation of Combustible Gas Control Discrepancy
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cc: Mr. H1111am Russell
Regional Administrator, Region I
U.S. Nuclear Regulatory Commission
475 Allendale Rd.
King of Prussia, PA 19406
Sr. Resident Inspector - Pilgrim Station
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ATTACHMENT 1
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Resoonse to Unresolved Items
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(Inspection Report 88-11)
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NRC Unresolved Item 88-11-01
Exterot from Insor: tion Reoort. Section 4
Comparison of Plant Specific Technical Guidelines, BHR Owners Group Emergency
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Guidelines _and Emergency Ooerating Procedures (EOP's) -
Plant Specific Technical Guidelines (P-STG)/EOP Review
"All EOPs and those portions of satellite procedures which contained steps
based on the P-STGs were compared to the P-STG. The following differences
were noted.
"EOP-3:
Primary Containment Control"
"PSTG steps PC/H-2,1 (suppression chamber spray), 2.2 (torus or drywell
vent), 2.3 (purge), and 2.4 (drywell spray) were reordered in the E0P in the
order of:
2.2, 2.3, 2.1, 2.4.
The licensee had not previously identified
this potential safety-significant deviation.
Either analysis of the
acceptability of E0P sequence or procedure revision to match the PSTGs is
required.
This is an unresolved item (50-293/88-11-01)."
BECo Resconse to Unresolved Item 88-11-01
This condition has been evaluated and determined to not be a safety
significant deviation.
The detailed evaluation is provided as Attachment 2.
This item is a technical inaccuracy and will be corrected as part of the next
major revision to the E0Ps.
This discrepancy is formally captured as
verification discrepancy number D-7-2 for E0P-3.
NRC Unresolved Item 88-11-02
Exteret from Insoection Reoort. Section 8
"Walkthrough of Emeraency Ooeratina Procedures
and Satellite Procedures"
"A number of the E0P-related items identified by the inspectors h.ad also been
identified by the facility review process and actions were being taken to
address the observed problems.
However, the facility review of the satellite
procedures was still in progress even though the procedures were approved and
issued, i.e., they had not yet finished their own walkthrough of the
satellite procedures.
Furthermore, the operation management agreed to assure
that the plant labeling was consistent with the E0Ps and satellite
procedures.
Therefore, pending further NRC review following completion of
the facility walkthrough of the satellite procedures and the licensee actions
to correct the identified deficiencies, this item will remain unresolved
(50-293/88-11-02)."
Page 1 of 3
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ATTACHHENT 1 (cont'd)
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BECo Resco'nse to Unresolved Item 88-11-02
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Review of E0P satellite procedures has been completed.
The discrepancies
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identified by the NRC, including those identified in Attachment C of the
Inspection Report, and by walkdowns performed by PNPS licensed operators have
been corrected.
NRC Unresolved Item 88-11-03
Excerot from Insoection Reoort. Section 4
"P-STG/EOP Review"
"EOP-3:
Primary Containment Control"
"Primary contair. ment venting was allowed by procedure after torus pressure
exceeds 11 psig but before reaching the Primary Containment Pressure Limit
(PCPL; 48 psig) irrespective of resultant reactivity release rate.
Procedure
5.4.6 stated that venting, irrespective of resultant reactivity release rate,
was appropriate only when the primary containment pressure is above the PCPL
(or when drywell or torus hydrogen concentration was above 61.).
The licensee
stated that they will revise the procedures to remove the inconsistency and
instruct operators to vent before reaching the PCPL."
"Saf ellite Procedures Review"
"5 4.6:
Post Accident Containment Control (Ventina)"
"The procedure directed using both a small vent path (1 or 2 inch valves) and
a large path (through 8 inch valves) for containment venting.
In some
scenarios it inay not be necessary to open both sets of valves if after
opening only the 2 inch or the 1 inch valves the containment pressure is
cor trolled appropriately. The licensee agreed to revise the procedure or
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justify not revising it."
"A caution contained the words "If at all possible . ... shall ...".
This
statement did not provide clear direction to the SRO.
The licensee agreed to
revise the procedure or justify not revising it."
"Step 2 of Attachment A of this procedure stated that the E0P is applicable
when primary containment pressure ntarAe12.5 psig, as opposed to above 2.5
psig.
The licensee agreed to revise this statement."
"The caution statement about rupture of the ductwork with venting did not
include notification of Health Physics.
The licensee agreed to revise the
procedure or justify not revising it."
"Step 2 of Attachment A of this procedure was missing a statement regarding
opening the appropriate valves as necessary to perform the step. The
licensee agreed to consider revising this statement."
"Step 3 of Attachment A of this procedure did not provide clear direction to
the operator on the value of primary containment pressure to terminate torus
venting.
The licensee agreed to revise the procedure or justify not revising
it."
Page 2 of 3
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ATTACHMENT 1 (cont'd)
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"The ltems concerning containment venting will be collectively included as
part of unresolved items 50-293/88-11-03. See Section 8 for additional
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containment venting items."
Excerot from Insoection Reoort. Section 8"
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"One item identified during the walkthrough of the E0Ps was an apparent need
for additional training on when to initiate and when to terminate venting of
the containment in accordance with the intent of the EPGs and the
procedures.
Items concerning containment venting will be considered an
unresolved item (50-293/88-11-03.)"
BEco Resoonse to Unresolved Item 88-11-03
PNPS Procedure 5.4.6, "Primary Containment Venting and Purging Under
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Emergency Conditions" - Attachment A, has been revised (Revision 18) to
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correct all the identified discrepan:les.
Operator training on when to initiate and when to terminate venting, in
accordance with the intent of the PSTGs, is given as part of training module
87-0-RQ-05A-01-07.
The intent of venting is stressed to each operating crew.
NRC Unresolved Item 88-11-04
Excerot for Insoection Reoort. Section 11
"EOP Ouality Assurance Measures"
"A review was conducted to determine if Quality Assurance Measures are
adequate to ensure that high quality E0Ps are developed, implemented and
maintained."
"The QA measures associated with the development of the E0Ps were found to be
acceptable, based on discussions with the Quality Engineering Division
Manager and Senior Quality Engineer.
However, it was concluded that a
programmatic approach to ensure the continued quality of the E0Ps through
audits of the maintenance of the E0Ps did not exist in the area of auditing
of the E0P program."
"In subsequent discussions with the Vice President, Nuclear Engineering
Division and Quality Assurance management, 8ECo committed to revise the 1988
Internal Audit Schedule to include an annual audit of the E0P program.
This
audit will be performed as a Safety System Audit in the fourth quarter of
1988.
The proceduralization of continued quality assurance measures is an
Unresolved Item (50-293/88-11-04)."
BECo Resoonse to Unresolved Item 88-11-04
As indicated in the inspection report excerpt, the 1988 Quality Assurance
Audit Schedule was revised to include an annual audit of the E0P program
beginning in the fourth quarter of 1988.
The Audit Schedule revision was
formally approved March 17, 1988.
In addition Quality Assurance Department Procedure No. 18.01, "Preparation,
Performance, Reporting and Follow-up of Quality Assurance Department Internal
Audits" was revised on April 25, 1988 to reflect, an annual audit frequency
for the EOP program.
Page 3 of 3
ATTACHMENT 2
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EVALUATION OF THE E0P-PSTG DISCREPANCY
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RELATIVE TO
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COMBUSTIBLE GAS CONTROL
Nhen primary containment hydrogen and oxygen concentrations reach the
deflagration limits (6% and 5%, respectively), the PSTGs require wetwell
spraying, venting, and purging in that order (PSTG Steps PC/H-2.1, 2.2, and 2.3).
Procedure 5.4.6 (Rev. 17) specifies that venting precede purging. However E0P-3
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(Rev. 0) does not specify that wetwell spraying should precede the vent and purge
evolution.
The effect of this dis:repancy between the PSTGs and the E0Ps may be evaluated by
examining all events to which E0P-3 may apply. All such events may be segregated
into two classes:
those for which the containment remains inerted (i.e., oxygen
concentration remains below 5%) throughout the event and those for which it does
not.
Events within the former class are not affected by the E0P discrepancy
because the conditions required for execution of the discrepant step, hydrogen
and oxygen concentrations reaching their deflagration limits, are not met. Thus
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the discrepancy can affect only those events within the latter class.
This smaller set of potentially affected events, those for which the containment
does not remain inerted, may be further segregated into two additional classes:
those for which the containment is deinerted when the event initiates (e.g.,
events initiated within one of the 24-hour periods when power operation is
permitted without containment inertion) and those for which the containment
becomes deinerted during the event.
The Boston Edison Company has removed all
air sources from within the Pilgrim primary containment.
Therefore, with the
exception of deliberate deinertion, which is not called for in the EOPs, the
primary containment will become deinerted during an event only if its pressure is
reduced to the point at which the reactor-building-to-torus vacuum breakers open,
drawing air from the reactor building into the wetwell airspace. This will
happen only if containment temperatures are reduced to well below those which
existed when the event initiated, and the only viable mechanism for effecting
such temperature reductions is the prolonged operation of containment sprays.
However, the E0Ps preclude the use of containment sprays when containment
pressure is below 2.5 psig.
Thus the Pilgrim systems configuration together with
the EOPs preclude the containment from becoming deinerted during an event, so
that there are no events within the latter class and the EOP discrepancy can
affect only those events within the former.
This smaller set of potentially affected events, those which initiate during a
period when the containment hns been deinerted, may be further segregated into
two classes:
those which initiate before the reactor has developed a significant
power history (i.e., startup events) and those which initiate afterwards. With
no significant power history, the reactor core cannot develop decay heat
sufficient to generate enough hydrogen to approach the hydrogen deflagration
limit.
Events within the former class are therefore not affected by the EOP
discrepancy because the conditions required for execution of the discrepant step,
hydrogen and oxygen concentrations reaching their deflagration limits, are not
met.
Thus the discrepancy can affect only the events within the latter class.
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ATTACHMENT 2 (cent'd)
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This smaller set of potentially affected events, those which initiate during a
period when the containment has been deinerted but only after the reactor has
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developed a significant power history, may be further segregated into two
additional classes:
loss of coolant accidents (LOCAs) and non-LOCAs. During a
LOCA the steam released into the drywell will quickly increase containment
pressure to the Suppression Chamber Spray Initiltion Pressura (refer to the
definition of the SCSIP in Appendix A of the BHORG EPGs), and this will occur
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before any appreciable hydrogen can be generated.
E0P-3 requires initiation of
wetwell sprays before containment pressure reaches SCSIP, so that the operator
will have been directed to operate wetwell sprays before the conditions required
for execution of the discrepant step, hydrogen and oxygen concentrations reaching
their deflagration limits, are met. Thus the E0Ps will require wetwell spraying
before the vent and purge evolution for any event within the former class, so
that the EOP discrepancy can affect only those events within the latter.
This smaller set of potentially affected events, non-LOCAs which initiate during
a period when the containment has been deinerted but only after the reactor has
developed a significant power history, may be further segregated into two
additional classes: those for which adequate core cooling is maintained and those
for which it is not.
If adequate core cooling is maintained then no significant
hydrogen generation occurs and the conditions required for execution of the
discrepant step, hydrogen and oxygen concentrations reaching their deflagration
limits, are not met.
Thus the discrepancy can affect only those events within
the latter class.
This smaller set of potentially affected events, non-LOCAs, with loss of adequate
core cooling which initiate during a period when the containment has been
deinerted but only af ter the reactor has developed a significant power history,
may be further segregated into two additional classes:
those which generate
sufficient hydrogen to reach the deflagration limit and those which do not.
Clearly events within the latter class are not affected by the E0P discrepancy
because the conditions required for execution of the discrepant step, hydrogen,
and oxygen concentrations reaching their deflagration limits, are not met. Thus
the discrepancy can affect only those events within the former class.
This smaller set of potentially affected events, non-LOCAs with loss of adequate
core cooling, which generate sufficient hydrogen to reach the deflagration limit,
and which initiate during a period when the containment has been deinerted but
only after the reactor has developed a significant power history, must be further
reduced to actually define the set of events which can be affected by the E0P
discrepancy.
As a minimum, the following subsets of events must be excised:
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Events in which the RPV is blown down to the suppression pool after the pool
has been substantially heated. The E0Ps require that the RPV be rapidly
depressurized prior to loss of adequate core cooling and, therefore, prior to
any significant hydrogen generation.
If the RPV is depressurized by blowing
down to the suppression pool, then the thermal energy transferred to the pool
will raise the wetwell water temperature, which in turn raises the partial
pressure of the water vapor in the wetwell airspace and the temperature and
partial pressure of the dry gas in the airspace.
If the wetwell water
temperature is relatively high when the blowdown is initiated, this will be
sufficient to raise containment pressure to the Suppression Chamber Spray
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Initiation Pressure.
E0P-3 requires initiation of wetwell sprays before
containment pressure reaches the SCSIP, so that the operator will have been
directed to operate wetwell sorays before the Londitions required for
execution of the discrepant step, hydrogen and oxygen concentrations reaching
their deflagration limits, are met.
Thus the E0Ps will require wetwell
spraying before the vent and purge evolution for these events.
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ATTACHMENT 2 (cont'd)
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2.
significant hydrogen generation occurs. Events in which safety
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Because the Pilgrim safety valves
are unpiped, any continued steam discharge through these valves will raise
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containment pressure to the Suppression Chamber Spray Initiation Pressur
E0P-3 requires initiation of wetwell sprays before containment pressure
reaches the SCSIP, to that the operator will have been directed to operate
wetwell sprays before the conditions required for execution of the discr
step, hydrogen and oxygen concentrations reaching their deflagration
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are met.
Thus the EGPs will require wetwell spraying before the vent and
purge evolution for these events.
3.
the SRVs are inoperable). Events in which the main condenser is utiliz
For these events, any hydrogen generated will be
discharged through the offgas system and will therefore not accumulate in
discrepant step, hydrogen and oxygen concentrations reachin
deflag ation limits, are not met for these events.
4.
Events in which reactor core decay heat cannot be effectively removed from
the primary containment for a prolonged period before significant hydrogen
generation occurs.
the pool will raise the wetwell water temperature, which in
partial pressure of the water vapor in the vetwell airspace and the
temperature and partial pressure of the dry gas in the airspace.
If this
Suppression Chamber Spray Initiation Pressure. occurs over a prolo
E0P-3 requires initiation of
wetwell sprays before containment pressure reaches the SCSIP, so that the
operator will have been directed to operate wetwell sprays b(fore the
conditions required for execution of the discrepant step, hydrogen and oxyge
concentrations reaching their deflagration limits, are met.
Thus the E0Ps
will require wetwell spraying before the vent and purg0 evolution for these
events.
the preceding logic.Thus the set of avents which may be affected by the E0P
set is vanishingly small and clearly does not warrant correction of t
discrepancy in ';he near term (i.e., before the E0Ps undergo their next revision).
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